ORCID Profile
0000-0002-6691-1937
Current Organisation
Hong Kong Baptist University
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Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D2TC05503A
Abstract: Single-component WLEDs with tunable CCT from 3303 to 8055 K and very high CRI have been realized using ZnO-QDs as emissive layer, which opens up a new avenue for the development of low-cost, environment-friendly, and high-performance single-component WLEDs.
Publisher: Wiley
Date: 30-01-2020
Publisher: Springer Science and Business Media LLC
Date: 24-04-2014
Abstract: In this study, the properties of blue organic light-emitting diodes (OLEDs), employing quantum well-like structure (QWS) that includes four different blue emissive materials of 4,4′-bis(2,2′-diphenylyinyl)-1,1′-biphenyl (DPVBi), 9,10-di(naphth-2-yl)anthracene (ADN), 2-( N , N -diphenyl-amino)-6-[4-( N , N -diphenyl amine)styryl]naphthalene (DPASN), and bis(2-methyl-8-quinolinolate)-4-(phenyl phenolato) aluminum (BAlq), were investigated. Conventional QWS blue OLEDs composed of multiple emissive layers and charge blocking layer with lower highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) energy level, and devices with triple emissive layers for more significant hole-electron recombination and a wider region for exciton generation were designed. The properties of triple emissive layered blue OLEDs with the structure of indium tin oxide (ITO) / N , N ′-diphenyl- N , N ′-bis(1-naphthyl-phenyl)-(1,1′-biphenyl)-4,4′-diamine (NPB) (700 Ǻ)/X (100 Ǻ)/BAlq (100 Ǻ)/X (100 Ǻ)/4,7-diphenyl-1,10-phenanthroline (Bphen) (300 Ǻ)/lithium quinolate (Liq) (20 Ǻ)/aluminum (Al) (1,200 Ǻ) (X = DPVBi, ADN, DPASN) were examined. HOMO-LUMO energy levels of DPVBi, ADN, DPASN, and BAlq are 2.8 to 5.9, 2.6 to 5.6, 2.3 to 5.2, and 2.9 to 5.9 eV, respectively. The OLEDs with DPASN/BAlq/DPASN QWS with maximum luminous efficiency of 5.32 cd/A was achieved at 3.5 V.
Publisher: Wiley
Date: 23-10-2020
Publisher: American Chemical Society (ACS)
Date: 28-07-2021
Abstract: The present full-color imaging techniques rely on the use of broadband inorganic photodetectors with dedicated color filters, which is one of the practical challenges for large-area, flexible, and high-solution imaging applications. The development of high-performance color-selective photodetectors is one of the key solutions to overcome this challenge. In this work, an electrically switchable color-selective organic photodetector (OPD) comprising a double organic bulk heterojunction structure has been developed for full-color imaging. The color-selective sensing capability over the visible spectrum ranges can be realized by controlling the bias across the OPD, achieving a high responsivity of ∼200 mA/W, a large linear dynamic range of 122 dB, a viewing angle of 120°, and a -3 dB cutoff frequency of >50 kHz. A full-color imaging function has been demonstrated using electrically switchable red-, green-, and blue-color selective OPD sensors with an excellent operational stability. The results of this work provide a practical solution for applications in high-resolution full-color imaging and artificial vision.
Publisher: ACM
Date: 31-10-2005
Publisher: AIP Publishing
Date: 24-08-2018
DOI: 10.1063/1.5031062
Abstract: Applying the optical transfer matrix method and the drift-diffusion equations, the efficient light absorption, exciton generation, and recombination rate in bulk heterojunction (BHJ) organic solar cells (OSCs) with conventional and inverted configurations are studied. Analysing the influence of the electric field component of the electromagnetic radiation propagating through the layered structure of BHJ OSCs and using contour plots of normalized modulus squared of the electric field, the constructive interference points (CIPs) which represent the positions of maximum absorption of photons and hence generation of excitons within the active layer are investigated for both the conventional and inverted OSCs. Also, the influence of the thicknesses of other layers in both the inverted and conventional structures is investigated. It is found that except the thickness of MoO3 in the inverted structure the thicknesses of other layers do not have any significant influence on CIPs. The maximum CIP occurs at an active layer thickness of 190 nm, regardless of the thickness of the second layer, which is MoO3, Ag, or ITO in the inverted structure and PEDOT:PSS, Al, or ITO in the conventional structure. The results of 3D plots of the normalized modulus squared of the electric field reveal that the absorption of photons at the end of the active layer in the inverted structure is higher than that in the conventional structure for all the effective wavelengths and different active layer thicknesses. It is expected that this study provides a deeper understanding of exciton generation within the two structures.
Publisher: Elsevier BV
Date: 03-2020
Publisher: American Scientific Publishers
Date: 2013
Abstract: High efficiency blue organic light emitting diodes (OLEDs), based on 2-me-thyl-9,10-di(2-naphthyl) anthracene (MADN) doped with 4,4'-bis(9-ethyl-3-carbazovinylene)-1,1'-biphenyl (BCzVBi), were fabricated using two different electron transport layers (ETLs) of tris(8-hydroxyquinolino)-aluminum (Alq3) and 4,7-di-phenyl-1,10-phenanthroline (Bphen). Bphen ETL layers favored the efficient hole-electron recombination in the emissive layer of the BCzVBi-doped blue OLEDs, leading to high luminous efficiency and quantum efficiency of 8.34 cd/A at 100 mA/cm2 and 5.73% at 100 cd/m2, respectively. Maximum luminance of blue OLED with Bphen ETL and Alq3 ETL were 10670 cd/m2, and CIExy coordinates of blue OLEDs were (0.180, 0279) and (0.155, 0.212) at 100 cd/m2.
Publisher: Elsevier BV
Date: 06-2018
Publisher: Wiley
Date: 11-01-2005
Publisher: Wiley
Date: 27-03-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TC06078A
Abstract: Solution processable near infrared (NIR) photodetectors provide a promising alternative due to their low cost, flexible design, adaptability to various fabrications, and large area manufacturability, removing the limitations of traditional wafer-based inorganic semiconductor techniques. High performing NIR photodetectors offer attractive options for applications in visualizing NIR light, health and safety monitoring.
Publisher: American Chemical Society (ACS)
Date: 09-01-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8TC03557A
Abstract: The non-phosphor-doped four-color WOLED simultaneously achieves high EQE of 19.35% and high CRI of 93.
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3RA44414G
Publisher: AIP Publishing
Date: 20-04-2015
DOI: 10.1063/1.4919106
Abstract: High efficiency, broadband plasmonic absorbers are constructed based on a stack of alternating metallic nanoparticle layers (MNLs) and SiO2 slabs on top of a reflective Ag substrate. Experimental results show that the stacks with thick MNLs absorb light better than those with thin MNLs when the number of MNL/SiO2 cells (N) is small (e.g., 1 or 2), but the situation gets reversed when N is greater than 3. When the nominal thickness of MNL is as thin as 5 nm, the acquired Ag nanoparticles are so small that light penetration through all of the stacked MNLs in the proposed design is possible. Thus, an increase in N leads to a growing number of light trapping elements. Our simulation reveals that the Ag nanoparticles at different layers are hybridized to excite rich localized plasmonic resonances, resulting in multiple absorption peaks at optical frequencies and thus a broader absorption band. The broadband absorbers with an integrated absorption efficiency of 96% over the 300–1100 nm wavelength range were achieved by stacking 18 MNL/SiO2 cells. The proposed absorbers can be used for applications in solar energy harvesting and thermal emission tailoring, due to their easy fabrication procedure and excellent optical properties.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4NJ01810A
Abstract: New π-conjugated alternating donor–acceptor polymers, based on functionalized imide acceptor structures with the 2,5-dithienylthieno[3,2- b ]thiophene (DTT) donor structure, were successfully synthesized and their properties were studied.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2009
Publisher: American Association for Cancer Research (AACR)
Date: 10-2014
DOI: 10.1158/1538-7445.AM2014-2106
Abstract: Prostate cancer, a hormone-dependent disease of aging men, occurs as the relative levels of estrogen compared to testosterone are increasing. Indeed, high doses of estrogen, in combination with androgens, can initiate prostate cancer. This effect is attributed to the activity of the estrogen receptor α (ERα), but a paucity of suitable models means that the precise role of ERα in prostate cancer is still poorly understood. In this study we observed increased ERα expression in three different models of prostate cancer, PTEN null mice, Hi-Myc mice, and high grade human tumor specimens. Within the PTEN null prostate, there was a consistent pattern of ERα expression: low in benign glands, moderate in tumors within the dorsal, lateral and ventral lobes, and high in tumors within the anterior prostate. This pattern significantly correlated with the levels of the proliferative marker Ki67. There was also a significant correlation between ERα and Ki67 within in idual malignant glands in the anterior prostate. Furthermore, we demonstrated that ERα sustained the in vitro proliferation of cells derived from a PTEN null tumor in 2D and 3D assays. There was a significant decrease in proliferation in cells treated with TPSF, a non-competitive ERα antagonist, or with ERα-specific shRNA. Loss of ERα caused a significant decrease in the levels of MYC and other ERα target genes. It also reduced the activity of both the PI3K and MAPK pathways as measured by decreased levels of phosphorylated erk1/2, S6 kinase and other downstream factors. This effect was reversed in rescue experiments with expression constructs for both full length ERα, capable of genomic and non-genomic actions, and membrane-only ERα, only able to trigger rapid non-genomic signalling. Collectively, these results demonstrate that ERα levels increase in prostate cancer, which promotes proliferation through classical genomic and rapid non-genomic signalling. Citation Format: Itsuhiro Takizawa, Mitchell Lawrence, Helen Pearson, John Pedersen, Normand Pouliot, Australian Prostate Cancer BioResource, Patrick Humbert, Luc Furic, Gail Risbridger. Estrogen receptor alpha drives proliferation of prostate cancer through PI3K and MAPK signaling. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research 2014 Apr 5-9 San Diego, CA. Philadelphia (PA): AACR Cancer Res 2014 (19 Suppl):Abstract nr 2106. doi:10.1158/1538-7445.AM2014-2106
Publisher: Elsevier BV
Date: 08-2011
Publisher: MDPI AG
Date: 27-06-2018
DOI: 10.3390/NANO8070473
Publisher: Elsevier BV
Date: 11-2014
Publisher: American Chemical Society (ACS)
Date: 13-07-2022
Publisher: AIP Publishing
Date: 10-06-2002
DOI: 10.1063/1.1484544
Abstract: We report the use of an in situ four-point probe method to investigate the relation between oxygen plasma treatment on indium tin oxide (ITO) and the variation in its sheet resistance. Analyses on the ITO surface composition made with time-of-flight secondary ion mass spectroscopy probe a dual-layer parallel resistor model for oxygen plasma-treated ITO anodes. We have shown that the increase in the ITO sheet resistance can be attributed to the reduction of oxygen deficiency near the surface. The improvement in carrier injection in phenyl-substituted poly(p-phenylenevinylene)-based light-emitting diodes correlates directly with a layer of low conductivity, several nanometers thick. This was induced on the ITO surface and serves as an efficient hole injecting anode.
Publisher: American Chemical Society (ACS)
Date: 13-10-2017
DOI: 10.1021/ACS.JPCLETT.7B02308
Abstract: We report our effort to unravel the origin of efficient operation of nonfullerene organic solar cells (OSCs), based on a poly[4,8-bis(5-(2-ethylhexyl) thiophen-2-yl)benzo[1,2-b ,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)](PTB7-Th):3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2',3'-d']-s-indaceno [1,2-b:5,6-b']dithiophene (ITIC) blend system. The effects of buildup of space charges, charge extraction, and bimolecular recombination processes on the performance and the stability of PTB7-Th:ITIC-based regular and reverse configuration OSCs are analyzed. It is found that the high-performing inverted PTB7-Th:ITIC OSCs benefit from the combined effects of (1) suppression of bimolecular recombination enabled by an augmented effective internal electric field and (2) improvement of charge extraction by avoiding the holes passing through ITIC-rich region, which would otherwise occur in a regular configuration cell. The inverted PTB7-Th:ITIC OSCs possess a significant improvement in the cell stability and a high power conversion efficiency of ∼8.0%, which is >29% higher than that of an optimized regular configuration control cell (6.1%).
Publisher: AIP Publishing
Date: 03-11-2008
DOI: 10.1063/1.3013845
Abstract: High performance organic field effect transistors using a solution-processable processed trilayer sol-gel silica gate dielectric architecture fabricated on plastic substrates exhibited low driving voltages of −3.0V, high saturation mobilities of ∼3.5cm2∕Vs, and on-off current ratio of 105. The enhancement in field effect mobility is attributed to improved dielectric-semiconductor interfacial morphology and increased capacitance of the tristratal dielectric. The pentacene devices displayed no signs of electrical degradation upon bending through a bending radius of 24mm, 2.27% strain. The slight increase in the drain currents upon bending strain was investigated using Raman spectroscopy, which revealed enhanced in-phase intermolecular coupling.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TC06229C
Abstract: Broadband phototransistors (PTs) with a bi-layer MAPbI 3 /NIR light absorbing polymer channel have the advantages of the complementary absorption and high charge transport efficiency of the two materials. The broadband PTs possess simultaneously a specific detectivity ( D *) of 9 Jones over the wavelength range from UV to visible light and a high D * of 7 Jones over the NIR light wavelength range.
Publisher: AIP Publishing
Date: 05-03-2007
DOI: 10.1063/1.2711657
Abstract: This letter reports our efforts to improve the power conversion efficiency (PCE) and the optical transparency of semitransparent poly(3-hexylthiophene) (P3HT):1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C60 (PCBM) based photovoltaic (PV) cells. Semitransparent P3HT:PCBM based solar cells were prepared based on parameters obtained by optical admittance analysis. The performance of structurally identical polymer PV cells made with a reflective calcium/silver cathode and a semitransparent Ca(10nm)∕Ag(10nm)/indium tin oxide cathode are compared. For semitransparent polymer PV cells with a 75nm thick active P3HT:PCBM blend layer, an average transmission of more than 30% was achieved with a high PCE of 1.7% under simulated AM1.5G illumination of 100mW∕cm2.
Publisher: AIP Publishing
Date: 31-08-2009
DOI: 10.1063/1.3224191
Abstract: A structure of indium tin oxide/SiO2 embedded with Ge nanocrystal (nc-Ge) -Si substrate was fabricated. The capacitance of the structure can be switched to a high-capacitance or low-capacitance state by an ultraviolet (UV) illumination. The increase (or decrease) in the capacitance is accompanied with the decrease (or increase) in the oxide resistance. The capacitance switching is explained in terms of the UV illumination-induced charging and discharging in the nc-Ge.
Publisher: American Scientific Publishers
Date: 07-2008
DOI: 10.1166/JNN.2008.128
Abstract: The information of band structure of silicon nanocrystal (nc-Si) embedded in SiO 2 thin films synthesized by Si ion implantation and subsequent thermal annealing at various temperatures has been obtained from spectroscopy ellipsometric (SE) analysis. The indirect band structure and the energy gap of the nc-Si are not affected by the annealing. In contrast, the photoluminescence (PL) spectra show a continuous evolution with the annealing. Six PL bands located at 415, 460, 520, 630, 760, and 845 nm, respectively, have been observed depending on the annealing temperature. The annealing at 1100 °C yields the strongest PL band at 760 nm (∼1.63 eV) with the intensity much higher than that of all the other PL bands. Based on the knowledge of the band structure, the 760 nm-PL band could be attributed to the indirect band-to-band transition of the nc-Si assisted by the Si—O vibration of the nc-Si/SiO 2 interface with the stretching frequency of ∼1083 cm −1 (& sim0.13 eV). On the other hand, the first four PL bands mentioned above could originate from different extended defects in the oxide matrix, while the 845-nm PL band could be related to the interface luminescent centers.
Publisher: Wiley
Date: 07-05-2008
DOI: 10.1002/POLB.21449
Publisher: Elsevier BV
Date: 2004
Publisher: Elsevier BV
Date: 09-2013
Publisher: Wiley
Date: 08-06-2020
Abstract: Many progresses have been made in the advancement of solution‐processable high‐performance organic solar cells (OSCs), offering an encouraging alternative photovoltaic (PV) technology option to traditional solar cells. The solution processing capability provides OSCs with great fabrication flexibility for new device concepts, cell architectures, and applications including lightweight large‐area transparent and flexible PV modules. The unique transparency and flexible features also add an attractive artistic aspect to emerging OSCs for use on curved surfaces, portable electronics, and indoor appliances. However, the stability of the OSCs is still less than satisfactory compared with the conventional inorganic semiconductor solar cells. This work discusses the improvement of the operational stability of OSCs through analyses of the important issues of 1) unbalanced charge mobility, 2) vertical stratification in the bulk heterojunction, and 3) built‐in potential across the photoactive layer, and retaining a stable built‐in potential for enhancing the operational stability of OSCs.
Publisher: Elsevier BV
Date: 12-2010
Publisher: Wiley
Date: 30-07-2023
Abstract: Semitransparent organic solar cells (ST‐OSCs) can be made in different colors, allowing light to pass through, and yet absorb enough visible and near‐infrared (NIR) light to generate electricity. However, it remains a challenge to achieve high performing ST‐OSCs over the two competing indexes of power conversion efficiency (PCE) and average visible transmittance (AVT). This work reports an effort to develop record‐performance ST‐OSCs using a low/high index optical coupling layer (OCL) and a 2D photonic‐structured antireflective (AR) coating. High‐throughput optical screening is used to improve the understanding of OCL structure−performance relationships and the predicting of NIR absorption enhancement for ST‐OSCs. The concurrent use of a low/high index Na 3 AlF 6 (170 nm)/ZnS (110 nm) OCL, identified among about 200 thousand simulated device configurations and a 900 nm pitch‐sized 2D photonic‐structured AR coating, fabricated using nanoimprint lithography, enables the record‐performance ternary PM6:BTP‐eC9:L8‐BO‐based ST‐OSCs, achieving simultaneously a record‐high PCE of 15.2%, a high AVT of 32%, an impressive light utilization efficiency of 4.86%, and a favorable color‐rendering index of 82. The results of the ST‐OSCs demonstrated in this work provide an attractive option for a plethora of applications in self‐powered greenhouses and building‐integrated photovoltaic systems.
Publisher: Shanghai Institute of Optics and Fine Mechanics
Date: 2014
Publisher: Walter de Gruyter GmbH
Date: 19-01-2019
Abstract: All-solution-processed flexible organic solar cells (FOSCs) with high power conversion efficiency (PCE) are the prerequisite for application in low-cost, large-area, flexible, photovoltaic devices. In this work, high-performance, top-illuminated FOSCs using ultrathin Ag-modified graphite-coated poly(ethylene terephthalate) (PET) substrates are demonstrated. The ultrathin Ag-modified graphite/PET substrates have excellent electric conductivity, mechanical flexibility, and easy processability for FOSCs. A PCE of 5.31% for FOSCs, based on the blend system poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo [1,2-b:4,5-b′]dith-iophene- co -3-fluorothieno[3,4-b]thiophene-2-carboxylate]: [6,6]-phenyl-C7l-but-yric acid methyl ester, having a bilayer of MoO x /Ag upper transparent anode is demonstrated. Top-illuminated FOSCs with a transparent upper electrode of solution-processed Ag nanowires also yielded a PCE of 3.76%. All-solution-processed FOSCs exhibit excellent mechanical flexibility and retain % of the initial efficiency after 500 cycles of bending test. Furthermore, graphite-based electrodes demonstrate good heat-insulation properties. The outcomes of this work offer an alternative to fabricate high-performance, all-solution-processable, top-illuminated FOSCs, providing a commercially viable approach for application in large-area solar cells that can be prepared by printing and roll-to-roll fabrication processes.
Publisher: Springer Science and Business Media LLC
Date: 12-11-2014
DOI: 10.1038/SREP07009
Abstract: In this study, we report our effort to realize high performance single emissive layer three color white phosphorescent organic light emitting diodes (PHOLEDs) through sequential Dexter energy transfer of blue, green and red dopants. The PHOLEDs had a structure of ITO(1500 Å)/NPB(700 Å)/mCP:Firpic-x%:Ir(ppy) 3 -0.5%:Ir(piq) 3 -y%(300 Å)/TPBi(300 Å)/Liq(20 Å)/Al(1200 Å). The dopant concentrations of FIrpic, Ir(ppy) 3 and Ir(piq) 3 were adjusted and optimized to facilitate the preferred energy transfer processes attaining both the best luminous efficiency and CIE color coordinates. The presence of a deep trapping center for charge carriers in the emissive layer was confirmed by the observed red shift in electroluminescent spectra. White PHOLEDs, with phosphorescent dopant concentrations of FIrpic-8.0%:Ir(ppy) 3 -0.5%:Ir(piq) 3 -0.5% in the mCP host of the single emissive layer, had a maximum luminescence of 37,810 cd/m 2 at 11 V and a luminous efficiency of 48.10 cd/A at 5 V with CIE color coordinates of (0.35, 0.41).
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CP52974F
Abstract: In this work, we report our effort to understand the photocurrent generation that is contributed via electron-exciton interaction at the donor/acceptor interface in organic solar cells (OSCs). Donor/acceptor bi-layer heterojunction OSCs, of the indium tin oxide/copper phthalocyanine (CuPc)/fullerene (C60)/molybdenum oxide/Al type, were employed to study the mechanism of photocurrent generation due to the electron-exciton interaction, where CuPc and C60 are the donor and the acceptor, respectively. It is shown that the electron-exciton interaction and the exciton dissociation processes co-exist at the CuPc/C60 interface in OSCs. Compared to conventional donor/acceptor bi-layer OSCs, the cells with the above configuration enable holes to be extracted at the C60 side while electrons can be collected at the CuPc side, resulting in a photocurrent in the reverse direction. The photocurrent thus observed is contributed to primarily by the charge carriers that are generated by the electron-exciton interaction at the CuPc/C60 interface, while charges derived from the exciton dissociation process also exist at the same interface. The mechanism of photocurrent generation due to electron-exciton interaction in the OSCs is further investigated, and it is manifested by the transient photovoltage characteristics and the external quantum efficiency measurements.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TC06043F
Abstract: A sodium citrate-modified-PEDOT:PSS hole transporting layer assists in the growth of the perovskite crystal, and favors the charge collection in the perovskite solar cells.
Publisher: AIP Publishing
Date: 15-04-2013
DOI: 10.1063/1.4802723
Abstract: A semitransparent white organic light-emitting diode (WOLED) is produced based on a blue phosphorescence from iridium(III)[bis(4,6-difuorophenyl)-pyridinato-N,C2] picolinate and an orange phosphorescence from bis(2-(9,9-diethyl-9H-fluoren-2-yl)-1-phenyl-1H-benzoimidazol-N,C3) iridium(acetylacetonate). In this work, a hole-transporting layer of N,N′-diphenyl-N,N′-bis(1-naphthylphenyl)-1,1′-biphenyl-4,4′-diamine (NPB) and an electron-transporting layer of 3,5,3″,5″-tetra-3-pyridyl-[1,1′ ′,1″] terphenyl (B3PyPB) were used. B3PyPB has high electron mobility and a high triplet energy level. The use of B3PyPB helps to reduce the triplet quenching and also to confine the charge recombination in the emissive region of a single-host two-color WOLED. A bi-layer Ag (10 nm)/MoO3 (2.5 nm)-modified indium tin oxide anode and a cathode of Al (1.5 nm)/Ag (15 nm)/NPB (50 nm) were employed. The semitransparent WOLEDs thus developed have perfect symmetrical, bi-directional illumination characteristics, and the weak angular dependent EL emission spectra, which are beneficial for application in planar diffused lighting.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TC02149C
Abstract: Photoresponsivity of the photonic-structured organo-lead triiodide (CH 3 NH 3 PbI 3 ) perovskite photodetectors is less dependent on the angle of the incident light and has an enhanced omnidirectional photoresponse in the near infrared wavelength range.
Publisher: Elsevier BV
Date: 05-2019
Publisher: AIP Publishing
Date: 08-09-2014
DOI: 10.1063/1.4895675
Abstract: An opposite interfacial exciton dissociation behavior at the metal (Al)/organic cathode interface in regular and inverted organic solar cells (OSCs) was analyzed using transient photocurrent measurements. It is found that Al/organic contact in regular OSCs, made with the blend layer of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl]-[3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl]] (PTB7):3′H-Cyclopropa [8,25][5,6] fullerene-C70-D5h(6)-3′-butanoicacid,3′-phenyl-,methyl ester (PC70BM), always h ers the electron collection. However, this is not observed in their reverse geometry OSCs fabricated using the same PTB7:PC70BM blend system. The detrimental interfacial exciton dissociation in regular OSCs originates the compensation of field drifted photo-generated electrons at Al/organic interface. The unfavorable interfacial exciton dissociation can be eliminated, e.g., by interposing a ZnO-based interlayer between Al and organic layer, attaining an efficient electron collection, thereby power conversion efficiency.
Publisher: AIP Publishing
Date: 27-09-2010
DOI: 10.1063/1.3493177
Abstract: Zinc phthalocyanine (ZnPc): fullerene-C60 (C60)-based organic photovoltaic (OPV) with high power conversion efficiency (PCE) are fabricated. Homogeneously distributed grains of ∼40–50 nm are observed for the ZnPc:C60 blend layer deposited on bare indium-tin oxide (ITO) substrates. In contrast, the blend layer form grains of smaller lateral extensions (∼20–30 nm) on 3, 4-polyethylenedioxythiophene: polystyrenesulfonate modified ITO substrates. OPV fabricated on the former substrates show PCE of up to 3.9% that is about twice the PCE (1.9%) obtained for the devices on the latter substrates. This effect can be explained by better transport properties and reduced charge recombination of the blend layer on the bare ITO.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2010
Publisher: AIP Publishing
Date: 28-12-2009
DOI: 10.1063/1.3279135
Abstract: The effect of oxygen induced traps on charge mobility in bulk heterojunction solar cells using poly(3-hexylthiophene) (P3HT):l-(3-methoxycarbonyl)-propyl-l-phenyl-(6, 6) methanofullerene (PCBM) blend have been studied using photoinduced charge extraction by linearly increasing voltage (PhotoCELIV) technique. The solar cells exposed to oxygen exhibit dual PhotoCELIV peaks, whereas the solar cell without oxygen treatment show single PhotoCELIV peak with the charge mobility of the order of 10−4 cm2/V s. It is demonstrated that the oxygen treatment imbalance the charge mobility in the P3HT/PCBM photoactive layer, which affects the power conversion efficiency and lifetime of the solar cell. The single PhotoCELIV peak for the device without oxygen treatment indicates that the charge mobility is balanced, that causes the overlapping of electron and hole transients.
Publisher: Wiley
Date: 21-11-2021
Abstract: Organic photodetectors (OPDs) are promising for applications in flexible electronics due to their advantages of excellent photodetection performance, cost‐effective solution‐fabrication capability, flexible device design, and adaptivity to manufacturability. This review outlines the recent advances in the development of high‐performance OPDs and their applications in flexible electronics. The approaches to developing different noise reduction methods, filter‐free spectral selective detection, flexible OPDs, and scale‐up production of flexible OPDs through solution‐fabrication processes are discussed. Applications of the OPD technology ultimately result in the materialization of wearable units, flexible and compact information sensors at commercially viable costs, including wearable health self‐monitoring devices, flexible optical communication systems, and flexible large‐area image sensors.
Publisher: American Chemical Society (ACS)
Date: 26-01-2018
Abstract: In this work, we report the effort to develop high-efficiency inverted polymer solar cells (PSCs) by applying a solution-processable bilayer ZnO/carbon quantum dots (C-QDs) electron extraction layer (EEL). It is shown that the use of the bilayer EEL helps to suppress the exciton quenching by passivating the ZnO surface defects in the EEL, leading to an enhanced exciton dissociation, reduced charge recombination and more efficient charge extraction probability, and thereby achieving high power conversion efficiency (PCE). The inverted PSCs, based on the blend of poly{4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} and [6,6]-phenyl C71-butyric acid methyl ester, possess a significant improvement in PCE of ∼9.64%, which is >27% higher than that of a control cell (∼7.59%). The use of a bilayer ZnO/C-QD EEL offers a promising approach for attaining high-efficiency inverted PSCs.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8TC05988H
Abstract: The effect of the small molecule PBD additive on the performance of the all inorganic polycrystalline CsPbBr 3 -based PeLEDs was studied.
Publisher: IOP Publishing
Date: 28-11-2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3PY00961K
Publisher: AIP Publishing
Date: 15-05-2007
DOI: 10.1063/1.2713946
Abstract: We report a study on the influence of charge trapping on electroluminescence (EL) from Si nanocrystal (nc-Si) distributed throughout a 30nm SiO2 thin film synthesized by Si+ implantation into an oxide film thermally grown on a p-type Si substrate. The electron and hole trapping in the nc-Si located near the indium tin oxide gate and the Si substrate, respectively, cause a reduction in the EL intensity. The reduced EL intensity can be recovered after the trapped charges are released. A partial recovery can be easily achieved by the application of a positive gate voltage or thermal annealing at hot temperatures (e.g., 120°C) for a short duration. The present study highlights the impact of charging in the nc-Si on the light emission efficiency and its stability of nc-Si light-emitting devices.
Publisher: Elsevier BV
Date: 08-2003
Publisher: Wiley
Date: 29-05-2020
Publisher: American Chemical Society (ACS)
Date: 21-12-2020
Publisher: Wiley
Date: 04-02-2021
Abstract: Perovskite solar cells (PSCs) are an emerging photovoltaic technology. PSCs with a power conversion efficiency of 25.2% have been demonstrated. Apart from the encouraging progress made in the efficiency, continuous improvement in operational stability is essential if the PSC technology is to become one of the commercially viable photovoltaic options for applications in renewable energy. In parallel to the development of high‐performance PSCs using environmental‐friendly solution fabrication processes, incorporation of process‐compatible high‐quality metal oxide interlayers for enhancing the stability of PSCs, through passivating the interfacial defects at the perovskite/contact interfaces, enhancing charge extraction, and retarding of the moisture encroachment, is needed. This review discusses the recent research progresses made in the development of different metal oxide interlayers for applications in PSCs, highlighting the functions, process compatibility and advances in high performing stable PSCs.
Publisher: Elsevier BV
Date: 07-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3TA14284A
Publisher: Elsevier BV
Date: 11-2003
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA08018G
Abstract: Modification of the HTL helps to attain a high built-in potential ( V 0 ) across the BHJ by suppressing the interfacial reaction at the HTL/BHJ interface. It is critical to retain a high and steady V 0 to obtain efficient and stable nonfullerene OSCs.
Publisher: American Chemical Society (ACS)
Date: 18-03-2010
DOI: 10.1021/JP909064N
Publisher: IOP Publishing
Date: 22-11-2005
Publisher: Springer Science and Business Media LLC
Date: 19-04-2016
DOI: 10.1038/SREP24476
Abstract: Organic field-effect transistors (OFETs) represent a low-cost transistor technology for creating next-generation large-area, flexible and ultra-low-cost electronics. Conjugated electron donor-acceptor (D-A) polymers have surfaced as ideal channel semiconductor candidates for OFETs. However, high-molecular weight (MW) D-A polymer semiconductors, which offer high field-effect mobility, generally suffer from processing complications due to limited solubility. Conversely, the readily soluble, low-MW D-A polymers give low mobility. We report herein a facile solution process which transformed a lower-MW, low-mobility diketopyrrolopyrrole-dithienylthieno[3,2-b]thiophene (I) into a high crystalline order and high-mobility semiconductor for OFETs applications. The process involved solution fabrication of a channel semiconductor film from a lower-MW (I) and polystyrene blends. With the help of cooperative shifting motion of polystyrene chain segments, (I) readily self-assembled and crystallized out in the polystyrene matrix as an interpenetrating, nanowire semiconductor network, providing significantly enhanced mobility (over 8 cm 2 V −1 s −1 ), on/off ratio (10 7 ), and other desirable field-effect properties that meet impactful OFET application requirements.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2TC01494G
Abstract: The schematic diagram illustrating the energy level alignment of the functional layers in (a) a control PSC and (b) a PSC with the presence of a PMMA-induced interface dipole at the HTL erovskite interface, (c) the formation of an interface dipole.
Publisher: MDPI AG
Date: 17-09-2015
Publisher: AIP Publishing
Date: 10-08-2009
DOI: 10.1063/1.3204698
Abstract: Large-area, continuous, transparent, and highly conducting few-layered graphene films produced by chemical vapor deposition method were used as anode for application in photovoltaic devices. The noncovalent modification of the graphene films with pyrene buanoic acid succidymidyl ester improved the power conversion efficiency (PCE) to 1.71%. This performance corresponds to ∼55.2% of the PCE of a control device based on indium tin oxide (ITO) oly(3,4–ethylenedioxythiophene):poly(styrenesulfonate) oly(3-hexyl)thiophene: phenyl-C61-butyric acid methyl ester/LiF/Al electrodes (PCE=3.1%). This finding paves the way for the substitution of ITO in photovoltaic and electroluminescent devices with low cost graphene films.
Publisher: American Chemical Society (ACS)
Date: 30-08-2019
Publisher: Elsevier BV
Date: 2021
Publisher: Elsevier BV
Date: 11-2011
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TC03700G
Abstract: MoO 3 -induced oxidation in PEDOT:PSS hole contact enables improving its conductivity, work function and process compatibility for application in solution-processed transparent QD-LEDs, attaining a maximum luminous efficiency of 1.39 cd A −1 and a transparency of %.
Publisher: Elsevier BV
Date: 04-2016
Publisher: The Optical Society
Date: 10-03-2016
DOI: 10.1364/OE.24.00A592
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9TC05323A
Abstract: AuAg-NPrisms@SiO 2 were incorporated into quasi-2D perovskite PDs and improved performances were obtained. EQE of 1670%, R of 7.15 A/W and D * of 3.2 × 10 13 Jones were achieved. Crystallinity of the quasi-2D perovskite film was also improved.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Research Square Platform LLC
Date: 11-2022
DOI: 10.21203/RS.3.RS-2201972/V1
Abstract: Low-cost, solution-processed photomultiplication organic photodetectors (PM-OPDs) with external quantum efficiency (EQE) above unity have attracted enormous attention. However, their weak-light detection is unpleasant because the anode Ohmic contact causes exacerbation in dark current. Here, we introduce atomic-level chemical reaction in PM-OPDs which can simultaneously suppress dark current and increase EQE via depositing a 0.8 nm thick Al 2 O 3 by atomic layer deposition. Suppression in dark current mainly originates from the built-in anode Schottky junction as a result of work function decrease of hole-transporting layer of which the chemical groups can react chemically with the bottom surface of Al 2 O 3 layer at the atomic-level. Such strategy of suppressing dark current is not adverse to charge injection under illumination instead, responsivity enhancement is realized because charge injection can shift from cathode to anode, of which the neighborhood possesses increased photogenerated carriers. Consequently, weak-light detection limit of the Al 2 O 3 treated PM-OPD reaches a remarkable level of 2.5 nW/cm 2 , while that of the control is 25 times inferior. Meanwhile, the PM-OPD yields a record high EQE and responsivity of 4.31×10 8 % and 1.85×10 6 A/W, respectively, outperforming all other polymer-based PM-OPDs.
Publisher: AIP Publishing
Date: 08-11-2004
DOI: 10.1063/1.1815374
Abstract: Tris-(8-hydroxyquinoline)aluminum (Alq3), which is typically used as an electron transport material for organic light-emitting devices (OLEDs), was used in this study for OLED anode modification. The electronic structure at the indium tin oxide (ITO)/organic interface for improvement of carrier injection was studied using ultraviolet photoelectron spectroscopy. The interfacial analysis reveals that the barrier height at the ITO/organic interface can be varied from ∼0.6–1.08eV. It is demonstrated that the barrier for hole injection from an ITO anode to a hole transporting layer can be engineered by inserting an ultrathin interlayer of Alq3, a few nanometers thick. The presence of an Alq3 interlayer is shown to improve the current balance, leading to an enhancement in the electroluminecent efficiency and operational stability of OLEDs.
Publisher: AIP Publishing
Date: 22-07-2013
DOI: 10.1063/1.4816786
Abstract: High performance inverted bulk heterojunction organic solar cells (OSCs), based on the blend of poly[[4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b′] dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]] (PTB7): 3′H-Cyclopropa[8,25] [5,6]fullerene-C70-D5h(6)-3′-butanoicacid, 3′-phenyl-, methyl ester (PC70BM), were achieved using an aluminum-doped zinc oxide (AZO) front transparent cathode. A structurally identical PTB7:PC70BM-based OSC having an indium tin oxide (ITO) front cathode was also made for comparison studies. The surface of AZO and ITO was modified with a 10 nm thick solution-processed ZnO interlayer to facilitate the efficient electron extraction. This work yielded AZO-based OSCs with a promising power conversion efficiency of 6.15%, slightly lower than 6.57% of a control ITO-based OSC, however, a significant enhancement in the stability of AZO-based OSCs was observed under an ultraviolet (UV)-assisted acceleration aging test. The distinctive enhancement in the lifetime of AZO-based OSCs arises from the tailored absorption of AZO electrode in wavelength & nm, serving as a UV filter to inhibit an inevitable degradation in ITO-based OSCs caused by the UV exposure.
Publisher: Wiley
Date: 17-07-2022
Abstract: Semitransparent organic solar cells (ST‐OSCs) offer potentially more opportunities in areas of self‐powered greenhouses and building‐integrated photovoltaic systems. In this work, the effort to use a combination of solution‐processable gold nanobipyramids (AuNBPs)‐based hole transporting layer and a low/high dielectric constant double layer optical coupling layer (OCL) for improving the performance of ST‐OSCs over the two competing indexes of power conversion efficiency (PCE) and average visible transmittance (AVT) is reported. The fabrication and characterization of the ST‐OSCs are guided, at design and analyses level, using the theoretical simulation and experimental optimization. The use of a low/high dielectric constant double layer OCL helps enhancing the visible light transparency while reflecting the near‐infrared (NIR) photons back into the photoactive layer for light harvesting. NIR absorption enhancement in the ST‐OSCs is realized through the AuNBPs‐induced localized surface plasmon resonance (LSPR). The weight ratio of the polymer donor to nonfullerene acceptor in the bulk heterojunction is adjusted to realize the maximum NIR absorption enhancement, enabled by the AuNBPs‐induced LSPR, achieving the high‐performance ST‐OSCs with a high PCE of 13.15% and a high AVT of 25.9%.
Publisher: Wiley
Date: 21-04-2020
Abstract: Formamidinium‐based perovskite with optimal bandgap and improved thermal stability is a promising active material for application in perovskite solar cells (PSCs). The hybrid precursor solutions, formed by adding various smaller cations, are often used for improving the phase stability in PSCs. Herein, research to understand the aging effect of a methylammonium‐ and bromine‐free formamidinium precursor solution on the performance of FA 0.85 Cs 0.1 Rb 0.05 PbI 3 ‐based PSCs is reported. The results reveal that deterioration in the built‐in potential in the PSCs is closely associated with the formation of the secondary phase in the FA 0.85 Cs 0.1 Rb 0.05 PbI 3 active layer. The formation of the secondary phase in the active layer is related to the hydrolysis of the precursor solution. The suppression of the moisture encroachment greatly enhances the durability of the precursor solution and performance reproducibility of PSCs.
Publisher: Springer Science and Business Media LLC
Date: 22-01-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NJ00656J
Abstract: New perylenediimide-functionalized 9,9′-bifluorenylidene derivatives are synthesized and utilized as non-fullerene acceptors in BHJ organic solar cells.
Publisher: Elsevier BV
Date: 1979
Publisher: American Association for the Advancement of Science (AAAS)
Date: 31-01-2020
Abstract: A dual-mode photodetector with bias-switchable spectral response offers detection and monitoring in two distinct bands.
Publisher: AIP Publishing
Date: 05-03-2007
DOI: 10.1063/1.2711198
Abstract: The authors report the photon-induced conduction modulation in SiO2 thin films embedded with germanium nanocrystals (nc-Ge). The conduction of the oxide could be switched to a higher- or lower-conductance state by a ultraviolet (UV) illumination. The conduction modulation is caused by charging and discharging in the nc-Ge due to the UV illumination. If the charging process is dominant, the oxide conductance is reduced however, if the discharging process is dominant, the oxide conductance is increased. As the conduction can be modulated by UV illumination, it could have potential applications in silicon-based optical memory devices.
Publisher: MDPI AG
Date: 27-01-2022
DOI: 10.3390/NANO12030420
Abstract: Thermal stability, closely associated with the operating temperature, is one of the desired properties for practical applications of organic solar cells (OSCs). In this paper, an OSC of the structure of ITO/PEDOT:PSS/P3HT:PCBM/ZnO/Ag was fabricated, and its current-voltage (J-V) characteristics and operating temperature were measured. The operating temperature of the same OSC was simulated using an analytical model, taking into consideration the heat transfer, charge carrier drift-diffusion and different thermal generation processes. The simulated results agreed well with the experimental ones. It was found that the thermalization of charge carriers above the band gap had the highest influence on the operating temperature of the OSCs. The energy off-set at the donor/acceptor interface in the bulk heterojunction (BHJ) was shown to have a negligible impact on the thermal stability of the OSCs. However, the energy off-sets at the electrode/charge-transporting layer and BHJ/charge-transporting layer interfaces had greater impacts on the operating temperature of OSCs at the short circuit current and maximum power point conditions. Our results revealed that a variation over the energy off-set range from 0.1 to 0.9 eV would induce an almost 10-time increase in the corresponding thermal power generation, e.g., from 0.001 to 0.01 W, in the cells operated at the short circuit current condition, contributing to about 16.7% of the total solar power absorbed in the OSC.
Publisher: Springer Science and Business Media LLC
Date: 18-01-2006
Publisher: Wiley
Date: 03-03-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8TC02479K
Abstract: The OLEDs, having mixed hosts sandwiched between hole- and electron-transporting hosts, exhibit an EQE exceeding the theoretical limit and extremely small efficiency roll-off.
Publisher: AIP Publishing
Date: 07-04-2005
DOI: 10.1063/1.1900940
Abstract: An aluminum-laminated polyethylene terephthalate (Al-PET) is used as the substrate for flexible organic light-emitting devices (OLEDs). The efficient flexible electroluminescent devices have a top-emitting OLED architecture. An acrylic layer is formed on the Al-PET surface to improve the surface morphology and also the adhesion between the substrate and the anode. Poly(styrene sulfonate)-doped poly(3,4-ethylene dioxythiophene) was used as hole transporting layer. The light-emitting polymer used is a phenyl-substituted poly(p-phenylenevinylene). Bilayer anodes of Ag∕CFX and Ag/indium-tin oxide and a semitransparent top cathode were used for the flexible polymer OLEDs. For a flexible polymer OLED with a 110-nm-thick light-emitting polymer, it exhibited superior electrical and optical characteristics with a luminous efficiency of 4.56cd∕A at an operating voltage of 7.5V.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5PY00333D
Abstract: Incorporation of heteroatoms into D–A copolymers enhances the functional properties for applications of OSCs and OFETs.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2009
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9RA03307F
Abstract: A potential hyperbranched structure with fluorene- alt -carbazole branches, a 3D-structured SDF core, and green (CzhBrPI)2Ir(fpptz) and red Ir(piq)2acac adjusting light units is synthesized for efficient and stable sunlight-style white polymer light-emitting devices.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4RA13252A
Abstract: Pure phase kesterite Cu 2 ZnSnS 4 (CZTS) nanocrystals (NCs) were synthesized via a heating-up method utilizing thioacetamide as coordinating sulphur precursor. The formation mechanism of the CZTS NCs has been clarified.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Wiley
Date: 06-08-2021
DOI: 10.1002/EOM2.12134
Abstract: Improved efficiency and stability of the organic solar cells (OSCs) are the critical considerations for practical applications. The interface between the interlayer and bulk heterojunction has recently been shown as one of the weak links associated with the degradation in the nonfullerene acceptor (NFA)‐based OSCs. It shows that the removal of the interfacial chemical reactions between the 2‐(3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (INCN) moieties in NFA and poly(3,4‐ethylenedioxythiophene)‐polystyrene sulfonate (PEDOT:PSS) hole extraction layer (HEL) is desired for enhancing the device stability. In this work, we show that the use of a bilayer MoO 3 /antimonene HEL favors the operational stability in OSCs through maintaining a high built‐in potential and suppression of an undesired interfacial reaction between INCN moieties in NFA and the PEDOT structures in PEDOT:PSS. A power conversion efficiency of 16.68% is also obtained for the OSCs with a bilayer MoO 3 /antimonene HEL, prepared using a blend system of PM6:Y6, demonstrating its suitability for high‐performance OSCs. image
Publisher: Elsevier BV
Date: 02-2015
Publisher: Elsevier BV
Date: 2022
Publisher: AIP Publishing
Date: 15-06-2009
DOI: 10.1063/1.3148248
Abstract: Influence of thermal annealing on electroluminescence (EL) from multiple-Si-implanted silicon nitride films has been investigated. A reduced injection current and an enhanced EL intensity have been obtained simultaneously by increasing the annealing temperature, which results in a higher EL quantum efficiency. In addition, four emission bands are identified, and their peak energies, intensities, and full widths at half maxima are found to change with annealing temperature. A model is proposed to illustrate the carrier transport, the mechanisms of the four emission bands, and the evolution of the EL bands with annealing as well. The two major bands and the minor ultraviolet band are explained in terms of the recombination of the injected electrons in either the silicon dangling-bond (≡Si0) states or the nitride conduction band with the injected holes in either the band tail states above the nitride valence band or the valence band itself, while the minor near infrared band is attributed to the Si nanocrystals formed in the thin film.
Publisher: AIP Publishing
Date: 05-2015
DOI: 10.1063/1.4921993
Abstract: A comprehensive study on inverted organic solar cells (OSCs) with a moth’s eye nanostructured (MEN) active layer was carried out. Performance of the MEN-based OSCs and the corresponding control planar cells, fabricated with blend of poly[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-bA] dithiophene-2, 6-diyl][3-fluoro-2-[(2- ethylhexyl) carbonyl]thieno[3,4-b]-thiophenediyl] (PTB7):[6,6]- phenyl-C70- butyric-acid-methyl-ester (PC70BM) was analyzed. The efficiency of the MEN-based OSCs was optimized by adjusting the height of MEN pattern in the active layer. Our experimental and theoretical results reveal that the MEN pattern enhances light absorption in the PTB7:PC70BM active layer, especially over the long wavelength region. This leads to a 7.8% increase in short circuit current density and a 6.1% increase in power conversion efficiency over those of the control planar cell.
Publisher: AIP Publishing
Date: 26-01-2009
DOI: 10.1063/1.3068002
Abstract: Strong visible electroluminescence (EL) has been observed from a 30 nm silicon nitride thin film multiply implanted with Si ions and annealed at 1100 °C. The EL intensity shows a linear relationship with the current transport in the thin film at lower voltages, but a departure from the linear relationship with a quenching in the EL intensity is observed at higher voltages. The EL spectra show two primary EL bands including the predominant violet band at ∼3.0 eV (415 nm) and the strong green-yellow band at ∼2.2 eV (560 nm). Two weak bands including the ultraviolet band at ∼3.8 eV and the near infrared band at ∼1.45 eV emerge at high voltages. The evolution of each EL band with the voltage has been examined. The phenomena observed are explained, and the EL mechanisms are discussed.
Publisher: Wiley
Date: 28-08-2020
Publisher: Elsevier BV
Date: 07-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1TC02898G
Abstract: Using small size GO as hole injection materials, the fabricated green OLED with Ir(ppy) 3 as emitter achieves the maximum current efficiency, power efficiency, and EQE reaching 73.14 cd A −1 , 53.95 lm W −1 , and 20.63%, respectively.
Publisher: Springer Singapore
Date: 30-07-2014
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7TC04528J
Abstract: A tetra-chromatic hybrid WOLED exhibits good warm white emission, showing stable EL spectra with a maximum CRI of 94, and also reveals a high EQE of 17.71%.
Publisher: Elsevier BV
Date: 2018
Publisher: Elsevier BV
Date: 04-2016
Publisher: AIP Publishing
Date: 29-06-2009
DOI: 10.1063/1.3168523
Abstract: High-performance pentacene (μsat=6.3 cm2/V s) and poly(3-hexylthiophene) (μsat=0.43 cm2/V s) field effect transistors have been realized on flexible substrate with low operating voltage (& −5 V), utilizing a trilayer sol-gel silica gate dielectric. Furthermore, the permittivity of the dielectric was tuned from ∼7 to ∼10 by varying plasma treatments, allowing the study of charge carrier mobility variation with k. A 65% reduction in the saturation mobility of the devices was observed when k increases, suggesting that the energetic disorder at the interface between the active layer and the dielectric can be modulated by the high polarizability of the bulk dielectric.
Publisher: The Optical Society
Date: 09-04-2015
DOI: 10.1364/OE.23.00A471
Publisher: Wiley
Date: 24-10-2018
Publisher: Elsevier BV
Date: 09-2021
Publisher: Wiley
Date: 04-03-2011
DOI: 10.1002/POLA.24613
Publisher: American Chemical Society (ACS)
Date: 17-07-2023
Publisher: American Chemical Society (ACS)
Date: 08-04-2020
Publisher: IOP Publishing
Date: 10-10-2007
Publisher: Elsevier BV
Date: 03-2017
Publisher: Elsevier BV
Date: 11-2014
Publisher: American Chemical Society (ACS)
Date: 02-02-2005
DOI: 10.1021/JA043121Y
Abstract: Large-scale arrays of highly oriented hexagonal ZnO nanorods and nanotubes were fabricated on arbitrary ZnO-film-coated substrates using a low-temperature chemical-liquid-phase deposition method. The obtained nanoproducts were characterized, and the growth mechanism is proposed.
Publisher: AIP Publishing
Date: 25-05-2004
DOI: 10.1063/1.1719268
Abstract: The interaction of indium tin oxide (ITO) film with nitric oxide (NO) has been investigated in situ by a four-point probe and x-ray photoelectron spectroscopy (XPS). The XPS N 1s peak emerged at a high binding energy of 404 eV indicating that NO was molecularly adsorbed on ITO surface. The adsorption of NO on ITO surface also induced a 0.2 eV shift in its valence band maximum to the low binding energy side leading to an upward surface band bending. We have shown that the increase in the ITO sheet resistance was attributed to its surface band bending.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2008
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4TC01990C
Abstract: An enhancement of 19.2% in PCE is obtained by incorporating silica-coated silver nanoparticles into the buffer layer of organic solar cells.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7TC05554D
Abstract: High performance Alq 3 -based organic light emitting diodes are achieved by using magnetic nanoparticles oly(3,4-ethylenedioxythiophene) oly(styrenesulfonate) as the composite hole-injection layer through the advantageous combination of light-scattering, localized surface plasmon resonance and magnetic effect.
Publisher: Elsevier BV
Date: 12-2009
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 09-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7TC04631F
Abstract: Perovskite LEDs based on CsPbBr 3 powder led to 48 and 12 times enhancement in peak brightness, compared to the different molar ratio CsBr/PbBr 2 precursor solution devices, and reached 4590 cd m −2 .
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2008
Publisher: Wiley
Date: 07-04-2022
Abstract: The dual‐band organic photodetectors (OPDs) detect incoming light selectively in two different bands. This work demonstrates a bias‐switchable dual‐band OPD, achieving a fast‐switching speed of over 1000 times per second and a −3 dB cutoff frequency of 100 kHz for high‐speed optical communications in two distinct bands, e.g., near‐infrared (NIR) and visible light. Visible‐blind NIR detection with a high responsivity of 435 mA W –1 is realized for the OPDs operated under a small reverse bias of −1.0 V. NIR‐blind visible light detection with a responsivity of 325 mA W –1 is obtained for the OPDs operated under a low forward bias of 1.0 V. Dual‐channel NIR/visible optical communication technique has been demonstrated, providing an opportunity for a plethora of applications in information electronics and the Internet‐of‐Things.
Publisher: AIP Publishing
Date: 15-05-2007
DOI: 10.1063/1.2730560
Abstract: Si nanocrystals (nc-Si) with different sizes embedded in SiO2 matrix have been synthesized with various recipes of Si ion implantation. The influence of nanocrystal size on optical properties, including dielectric functions and optical constants, of the nc-Si has been investigated with spectroscopic ellipsometry. The optical properties of the nc-Si are found to be well described by the four-term Forouhi-Bloomer model. A strong dependence of the dielectric functions and optical constants on the nc-Si size is observed. For the imaginary part of the dielectric functions, the magnitude of the main peaks at the transition energies E1 and E2 exhibits a large reduction and a significant redshift in E2 depending on the nc-Si size. A band gap expansion is observed when the nc-Si size is reduced. The band gap expansion with the reduction of nc-Si size is in good agreement with the prediction of first-principles calculations based on quantum confinement.
Publisher: Royal Society of Chemistry (RSC)
Date: 2004
DOI: 10.1039/B405873A
Publisher: Elsevier BV
Date: 04-2005
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/C0CC00832J
Abstract: Anatase TiO(2) having different percentages of (001)/(101) surface demonstrated different behaviors for Li(+) ions insertion and much enhanced rate performance of Li-ion batteries.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8TC00303C
Abstract: We report our efforts to develop high performing all-solution-processable transparent inverted QD-LEDs by interposing an interface dipole between the ZnO ETL and the quantum dot light-emitting layer.
Publisher: Springer Berlin Heidelberg
Date: 2015
Publisher: Elsevier BV
Date: 08-2004
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TA06950G
Abstract: Recent progress in the development of OPVs, PPVs and QDPVs for indoor applications.
Publisher: American Scientific Publishers
Date: 02-2016
Publisher: Elsevier BV
Date: 2006
Publisher: AIP Publishing
Date: 28-09-2009
DOI: 10.1063/1.3237161
Abstract: The power conversion efficiency (PCE) of regioregular poly(3-hexylthiophene) (P3HT) and {6,6}-phenyl C61-butyric acid methylester (PCBM)-based polymer solar cells was increased using an ionic liquid-functionalized carbon nanoparticles (ILCNs) thin film-modified cathode. The PCE of P3HT:PCBM based-polymer solar cells with a conventional aluminum (Al)-only cathode was increased by 20%–30% when the identical devices were made with an ILCNs-modified Al cathode, but its PCE was 10% lower than that of devices with LiF/Al cathode, measured under AM1.5G illumination of 100 mW/cm2. The ILCN interlayer approach, however, offers practical advantages to LiF in terms of its solution-processability, which is compatible with low cost, large area, and flexible solar cell fabrication.
Publisher: American Scientific Publishers
Date: 05-2015
Abstract: White organic light emitting diodes (WOLEDs) were fabricated using blue, green and red emitting layers (EMLs). The device has a structure of ITO/NPB/EML/Alq3/Liq/Al. Here, to control the white color balance, the location of the blue EML in the WOLEDs was fixed and only the thickness of blue EML was changed while both thickness and position of the green and red EMLs were adjusted. When adjusting the thickness of blue EML, the occurrence area of recombination zone was changed to influence the green luminescence. When adjusting the location and thickness of red EML, it could be found that the current density is more sensitive to the location of red EML than its thickness. Furthermore, it was discovered that light was emitted due to the Förster energy transfer even if it was apart from the recombination zone. WOLEDs with a maximum luminance of 17,740 cd/m,2 an external quantum efficiency of 2.12% at 100 cd/m,2 CIE coordinates of (0.328,0.301) and a color temperature of 6,185 K were obtained.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 08-2005
Publisher: AIP Publishing
Date: 13-06-2011
DOI: 10.1063/1.3599557
Abstract: The significant enhancement in power efficiency of tandem organic light-emitting diodes (OLEDs) was achieved using bulk heterojunction organic bipolar charge generation layer (CGL), consisted of zinc phthalocyanine (ZnPc): fullerene (C60) blend. In addition to a significant enhancement in luminance and current efficiency this work yielded a maximum power efficiency of 21 lm W−1 for a tandem OLED, notably almost two times higher than that of a single-unit device, with a maximum power efficiency of 10.1 lm W−1. The enhancement in power efficiency at higher luminance is also over 50%. The remarkable enhancement in power efficiency has been attributed to the effective charge generation, transport and extraction due to the presence of interface-modified ZnPc:C60 CGL in tandem OLEDs. Our results demonstrate that the bulk heterojunction, consisting of two matched n- and p-type organic semiconductors, is a promising bipolar CGL for high power efficiency tandem OLEDs.
Publisher: Elsevier BV
Date: 05-2006
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6TC05325D
Abstract: A well-controlled one-step method, assisted by sec -butyl alcohol solvent engineering and N , N -dimethylformamide solvent annealing under an N 2 atmosphere, is developed for the growth of a high quality CH 3 NH 3 Pb (1−x) Sn x I 3 perovskite film.
No related grants have been discovered for Furong Zhu.