ORCID Profile
0000-0002-6599-745X
Current Organisation
Queensland University of Technology (QUT)
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Structural Chemistry and Spectroscopy | Nonlinear Optics and Spectroscopy | Physical Chemistry (Incl. Structural)
Expanding Knowledge in the Chemical Sciences | Expanding Knowledge in the Physical Sciences |
Publisher: Elsevier BV
Date: 10-2019
Publisher: IEEE
Date: 07-2019
Publisher: AIP Publishing
Date: 20-11-2006
DOI: 10.1063/1.2396927
Abstract: Flexible thin film solar cells based on a pentacene/C60 heterojunction on indium tin oxide coated polyethylene terephthalate (PET) substrates are described. Devices grown on PET are compared to those on glass substrates. The nature of the organic grains grown on PET and glass substrates is shown to have a significant impact on the device short circuit current. Device performance under mechanical strain and elevated temperature is reported. Devices deliver an 8.8mAcm−2 short circuit current density with a 1.6% power conversion efficiency under an AM1.5 simulated solar intensity of 80mWcm−2. The relatively low 300mV open circuit voltage appears to limit device efficiency.
Publisher: IOP Publishing
Date: 06-01-2006
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9RA00148D
Abstract: A porous and conductive gate electrode of PEDOT:PSS and sulphonated mesoporous silica nanoparticles is investigated for organic thin film transistor sensors.
Publisher: Elsevier BV
Date: 05-2019
DOI: 10.1016/J.MEDIA.2019.01.002
Abstract: In the past decade, medical robotics has gained significant traction within the surgical field. While the introduction of fully autonomous robotic systems for surgical procedures still remains a challenge, robotic assisted interventions have become increasingly more interesting for the scientific and clinical community. This happens especially when difficulties associated with complex surgical manoeuvres under reduced field of view are involved, as encountered in minimally invasive surgeries. Various imaging modalities can be used to support these procedures, by re-creating a virtual, enhanced view of the intervention site. Among them, ultrasound imaging showed several advantages, such as cost effectiveness, non-invasiveness and real-time volumetric imaging. In this review we comprehensively report about the interventional applications where ultrasound imaging has been used to provide guidance for the intervention tools, allowing the surgeon to visualize intra-operatively the soft tissue configuration in real-time and to compensate for possible anatomical changes. Future directions are also discussed, in particular how the recent developments in 3D/4D ultrasound imaging and the introduction of advanced imaging capabilities (such as elastography) in commercially available systems may fulfil the unmet needs towards fully autonomous robotic interventions.
Publisher: AIP Publishing
Date: 21-06-2010
DOI: 10.1063/1.3456374
Abstract: Color information is much less useful to machine vision systems than to people because the spectrum of light illuminating a scene is unknown. For scenes illuminated by daylight, color information can be made significantly more useful to machine vision systems if the scene is imaged using sensors with a specifically chosen combination of spectral responses. In this paper we show that detectors with a full width at half maximum of up to 100 nm can give good color discrimination, and that conjugated dendrimer chromophores have the spectral properties required to allow machine vision systems to confidently use color information.
Publisher: IEEE
Date: 2005
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: AIP Publishing
Date: 07-07-2014
DOI: 10.1063/1.4887316
Abstract: Photovoltaic performance in relation to charge transport is studied in efficient (7.6%) organic solar cells (PTB7:PC71BM). Both electron and hole mobilities are experimentally measured in efficient solar cells using the resistance dependent photovoltage technique, while the inapplicability of classical techniques, such as space charge limited current and photogenerated charge extraction by linearly increasing voltage is discussed. Limits in the short-circuit current originate from optical losses, while charge transport is shown not to be a limiting process. Efficient charge extraction without recombination can be achieved with a mobility of charge carriers much lower than previously expected. The presence of dispersive transport with strongly distributed mobilities in high efficiency solar cells is demonstrated. Reduced non-Langevin recombination is shown to be beneficial for solar cells with imbalanced, low, and dispersive electron and hole mobilities.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2022
Publisher: Wiley
Date: 26-03-2020
Publisher: Elsevier BV
Date: 07-2006
Publisher: Elsevier BV
Date: 02-2023
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-05-2021
Publisher: SPIE
Date: 25-08-2017
DOI: 10.1117/12.2273804
Publisher: Springer Science and Business Media LLC
Date: 08-07-2019
DOI: 10.1038/S41598-019-45867-9
Abstract: A recent and emerging application of organic light emitting diodes (OLEDs) is in wearable technologies as they are flexible, stretchable and have uniform illumination over a large area. In such applications, transmission of OLED emission through skin is an important part and therefore, understanding spectral changes associated with transmission of OLED emission through human skin is crucial. Here, we report results on transmission of OLED emission through human skin s les for yellow and red emitting OLEDs. We found that the intensity of transmitted light varies depending on the site from where the skin s les are taken. Additionally, we show that the amount of transmitted light reduces by ~ 35–40% when edge emissions from the OLEDs are blocked by a mask exposing only the light emitting area of the OLED. Further, the emission/electroluminescence spectra of the OLEDs widen significantly upon passing through skin and the full width at half maximum increases by nm and nm for yellow and red OLEDs, respectively. For comparison, emission profile and intensities of transmitted light for yellow and red inorganic LEDs are also presented. Our results are highly relevant for the rapidly expanding area of non-invasive wearable technologies that use organic optoelectronic devices for sensing.
Publisher: American Chemical Society (ACS)
Date: 28-12-2021
Publisher: Wiley
Date: 23-08-2020
Publisher: Wiley
Date: 21-10-2014
Abstract: Broad spectral coverage over the solar spectrum is necessary for photovoltaic technologies and is a focus for organic solar cells. We report a series of small-molecule, nonfullerene electron acceptors containing the [(benzo[c][1,2,5]thiadiazol-4-yl)methylene]malononitrile unit as a high electron affinity component. The optoelectronic properties of these molecules were fine-tuned with the objective of attaining strong absorption at longer wavelengths by changing the low-ionization-potential moiety. The electron-accepting function of these materials was investigated with poly(3-n-hexylthiophene) (P3HT) as a standard electron donor. Significant photocurrent generation in the near infrared region, with an external quantum yield reaching as high as 22 % at 700 nm and an onset >800 nm was achieved. The results support efficient hole transfer to P3HT taking place after light absorption by the acceptor molecules. A Channel II-dominated power conversion efficiency of up to 1.5 % was, thus, achieved.
Publisher: Springer International Publishing
Date: 10-2019
Publisher: Elsevier BV
Date: 08-2007
Publisher: Springer International Publishing
Date: 10-2019
Publisher: American Chemical Society (ACS)
Date: 27-01-2014
DOI: 10.1021/LA403951J
Abstract: Fullerene derivatives are commonly used as electron acceptors in combination with (macro)molecular electron donors in bulk heterojunction (BHJ) organic photovoltaic (OPV) devices. Understanding the BHJ structure at different electron donor/acceptor ratios is critical to the continued improvement and development of OPVs. The high neutron scattering length densities (SLDs) of the fullerenes provide effective contrast for probing the distribution of the fullerene within the blend in a nondestructive way. However, recent neutron scattering studies on BHJ films have reported a wide range of SLDs ((3.6-4.4) × 10(-6) Å(-2)) for the fullerenes 60-PCBM and 70-PCBM, leading to differing interpretations of their distribution in thin films. In this article, we describe an approach for determining more precisely the scattering length densities of the fullerenes within a polymer matrix in order to accurately quantify their distribution within the active layers of OPV devices by neutron scattering techniques.
Publisher: IEEE
Date: 08-2011
Publisher: American Chemical Society (ACS)
Date: 21-01-2022
Abstract: Confocal fluorescence microscopy provides a means to map charge carrier density within the semiconductor layer in an active organic thin film transistor (OTFT). This method exploits the inverse relationship between charge carrier density and photoluminescence (PL) intensity in OTFTs, originating from exciton quenching following exciton-charge energy transfer. This work demonstrates that confocal microscopy can be a simple yet effective approach to gain insight into doping and de-doping processes in OTFT sensors. Specifically, the mechanisms of hydrogen peroxide sensitivity are studied in low-voltage hygroscopic insulator field effect transistors (HIFETs). While the sensitivity of HIFETs to hydrogen peroxide is well known, the underlying mechanisms remain poorly understood. Using confocal microscopy, new light is shed on these mechanisms. Two distinct doping processes are discerned: one that occurs throughout the semiconductor film, independent of applied voltages and a stronger doping effect occurring near the source electrode, when acting as an anode with respect to a negatively polarized drain electrode. These insights offer important guidance to future studies and the optimization of HIFET-based sensors. More importantly, the methods reported here are broadly applicable to the study of a range of OTFT-based sensors. This work demonstrates that confocal microscopy can be an effective research tool in this field.
Publisher: SAGE Publications
Date: 2017
Abstract: To determine the perceptions of surgeons at both consultant and resident level to the difficulties of performing knee arthroscopy and to determine their willingness to adopt robotic technology. A questionnaire was designed to discern the attitude of orthopaedic consultants and residents to the technical challenges of performing knee arthroscopy and the possible role of robotically enhanced surgery. The questionnaire included 31 questions across five key domains. Iatrogenic damage to articular cartilage was thought to occur in at least 1 in 10 cases by 50% of respondents with 15% believing that it occurred in every case. One hundred or more procedures were thought to be necessary to overcome the learning curve by 40% of respondents and 77.5% believed that 50 procedures or above were necessary. Ninety-nine per cent of respondents agreed that higher technical skills would decrease unintended damage. Despite such difficulties with the procedure and no prior experience with robotic surgery, 47% of respondents see a role for semiautonomous arthroscopic systems in the future. Surgeons believe that knee arthroscopy is a difficult procedure with a long learning curve and a high incidence of iatrogenic cartilage damage. Many find it ergonomically challenging and have frustration with current tools and technology. This is the first study that highlights surgeons’ difficulties performing knee arthroscopy despite the commonly held attitudes that it is a straightforward procedure. Systems that are able to decrease these problems should improve patients’ outcomes and decrease the risk of harm.
Publisher: IOP Publishing
Date: 18-05-2012
DOI: 10.1088/0022-3727/45/22/225105
Abstract: We report the fabrication and electrical characteristics of structured-gate organic field-effect transistors consisting of a gate electrode patterned with three-dimensional pillars. The pillar gate electrode was over-coated with a gate dielectric (SiO 2 ) and solution processed organic semiconductors producing both unipolar p-type and bipolar behaviour. We show that this new structured-gate architecture delivers higher source–drain currents, higher gate capacitance per unit equivalent linear channel area, and enhanced charge injection (electrons and/or holes) versus the conventional planar structure in all modes of operation. For the bipolar field-effect transistor (FET) the maximum source–drain current enhancements in p- and n-channel mode were % and 28%, respectively, leading to p and n charge mobilities with the same order of magnitude. Thus, we have demonstrated that it is possible to use the FET architecture to manipulate and match carrier mobilities of material combinations where one charge carrier is normally dominant. Mobility matching is advantageous for creating organic logic circuit elements such as inverters and lifiers. Hence, the method represents a facile and generic strategy for improving the performance of standard organic semiconductors as well as new materials and blends.
Publisher: American Chemical Society (ACS)
Date: 20-09-2022
Publisher: Elsevier BV
Date: 04-2006
Publisher: Elsevier BV
Date: 04-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Publisher: Wiley
Date: 12-2022
DOI: 10.1002/INF2.12395
Abstract: This cover (DOI: 10.1002/inf2.12345 ) shows a multifunctional TPA‐azaBODIPY‐TPA small molecule with superior optoelectronic and photophysical properties. Material is shown to function as an efficient hole transport layer in perovskite solar cells reaching a power conversion efficiency of 17.4%, and as a robust electron donor in near‐infrared organic photodetectors absorbing light in the wavelength range of up to 800 nm. Offering two distinct optoelectronic functions, TPA‐azaBODIPY‐TPA is particularly attractive as it enables multi‐purpose applications while maintaining the ease of fabrication. image
Publisher: Wiley
Date: 05-10-2017
Publisher: American Vacuum Society
Date: 05-2006
DOI: 10.1116/1.2183160
Abstract: Organic photovoltaic devices offer a large technological potential as a renewable source of electrical energy because of their low cost and ease of processing. For the last few years, the interest in such devices has grown rapidly, allowing multiplication of the solar conversion efficiency by 5 within about 10years. The highest conversion efficiency obtained is now close to 5% with a spin-coated polythiophene-fullerene blend. For a better understanding of those polymer blend systems, we have fabricated a coevaporated solar cell from model molecules. The molecular blend was composed of sexithiophene (α,α′-dihexylsexithiophene, T6) as a donor and fullerene C60 as an acceptor. The influence of the T6:C60 proportion was studied for an active layer of 100nm thickness. The conversion efficiency obtained with the optimal proportion of T6:C60 (40–60) is 0.7%. Reverse bias annealing effect was studied by measuring the current-voltage characteristics after each postprocessing step. The conversion efficiency reached 1% but still remained much less than for the polymer bulk heterojunction. This major difference may come from the spontaneous phase separation which takes place in polymers to form an interpenetrated network.
Publisher: Elsevier BV
Date: 05-2005
Publisher: Elsevier BV
Date: 12-2012
Publisher: Wiley
Date: 03-09-2012
Publisher: Elsevier BV
Date: 09-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3TC30472H
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2010
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3TA10554G
Publisher: AIP Publishing
Date: 08-07-2005
DOI: 10.1063/1.1992659
Abstract: We report fabrication of a TiO2 interconnected network structure for photovoltaic applications, which was obtained using polystyrene-block-polyethylene oxide diblock copolymer as the templating agent. The synthetic method is simple and highly reproducible. The pore size of the structure is controlled by the amount of Ti precursor provided. The heterojunction solar cells consisting of a TiO2 porous network structure and poly (2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV) showed improved performance with a short circuit current of 3.25mA∕cm2 under AM 1.5 solar illumination. The achieved maximum external quantum efficiency for optimum MEH-PPV thickness was 34%.
Publisher: American Chemical Society (ACS)
Date: 27-05-2019
Abstract: The distributed sense of touch forms an essential component that defines real-time perception and situational awareness in humans. Electronic skins are an emerging technology in conferring an artificial sense of touch for smart human-machine interfaces. However, assigning a conformably distributed sense of touch over a large area has been challenging to replicate in modern medical, social, and industrial robots. Herein, we present a new class of soft tactile sensors that exploit the mechanisms of triplet-triplet annihilation, exciton harvesting, and a small Stokes shift in conjugated organic semiconductors such as rubrene. By multiplexing the electroluminescence and photosensing modes, we show that a compact optoelectronic array of multifunctional rubrene/fullerene diodes can accurately measure pressure, position, and surface deformation applied to an overlying elastomeric layer. The dynamic range of sensing is defined by mechanical properties of the elastomer. Such optoelectronic approach paves the way for soft, conformal, and large-area compatible electronic skins for medicine and robotics.
Publisher: American Chemical Society (ACS)
Date: 21-01-2014
DOI: 10.1021/PH400047B
Publisher: AIP Publishing
Date: 29-08-2011
DOI: 10.1063/1.3637041
Abstract: Loss of performance in large area devices is a major concern for organic solar cells. We present studies highlighting up-scaling loss mechanisms caused by interfacial resistance at organic-metal interface in pentacene/C60 heterojunction solar cells. Devices with different active areas and electrodes are investigated, revealing the origin of higher series resistance in large area devices. We also simulate influence of spatial non-uniformity and anisotropic charge collection in active layer through selective coverage using customized electrode geometries and identify grain boundaries as the dominating link behind loss in photocurrent generation and collection.
Publisher: Wiley
Date: 23-12-2020
Publisher: Wiley
Date: 25-04-2016
Abstract: Major growth in the image sensor market is largely as a result of the expansion of digital imaging into cameras, whether stand-alone or integrated within smart cellular phones or automotive vehicles. Applications in biomedicine, education, environmental monitoring, optical communications, pharmaceutics and machine vision are also driving the development of imaging technologies. Organic photodiodes (OPDs) are now being investigated for existing imaging technologies, as their properties make them interesting candidates for these applications. OPDs offer cheaper processing methods, devices that are light, flexible and compatible with large (or small) areas, and the ability to tune the photophysical and optoelectronic properties - both at a material and device level. Although the concept of OPDs has been around for some time, it is only relatively recently that significant progress has been made, with their performance now reaching the point that they are beginning to rival their inorganic counterparts in a number of performance criteria including the linear dynamic range, detectivity, and color selectivity. This review covers the progress made in the OPD field, describing their development as well as the challenges and opportunities.
Publisher: Elsevier
Date: 2020
Publisher: AIP Publishing
Date: 03-06-2013
DOI: 10.1063/1.4808386
Publisher: AIP Publishing
Date: 08-2007
DOI: 10.1063/1.2767619
Abstract: Molecular blends of pentacene: N, N′-ditridecylperylene-3, 4, 9, 10-tetracarboxylic diimide (PTCDI-C13H27) permit to cover the visible part of the solar spectrum with an absorption onset at 730nm. Although charge mobilities of pentacene and PTCDI are rather large, the efficiency of pentacene:PTCDI-C13H27 blended devices is still lower than that of poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methyl ester devices. Comparisons between experimental results and optical modeling indicate that more than 30% of the photocurrent is lost in the blend while the short circuit current should reach 13mAcm−2 in the absence of recombination processes.
Publisher: SPIE
Date: 19-08-2010
DOI: 10.1117/12.867735
Publisher: Elsevier BV
Date: 02-2008
Publisher: Wiley
Date: 07-07-2022
DOI: 10.1002/INF2.12345
Abstract: The versatile nature of organic conjugated materials renders their flawless integration into a erse family of optoelectronic devices with light‐harvesting, photodetection, or light‐emitting capabilities. Classes of materials that offer the possibilities of two or more distinct optoelectronic functions are particularly attractive as they enable smart applications while providing the benefits of the ease of fabrication using low‐cost processes. Here, we develop a novel, multi‐purpose conjugated small molecule by combining boron‐azadipyrromethene (aza‐BODIPY) as electron acceptor with triphenylamine (TPA) as end‐capping donor units. The implemented donor–acceptor–donor (D–A–D) configuration, in the form of TPA‐azaBODIPY‐TPA, preserves ideal charge transfer characteristics with appropriate excitation energy levels, with the additional ability to be used as either a charge transporting interlayer or light‐sensing semiconducting layer in optoelectronic devices. To demonstrate its versatility, we first show that TPA‐azaBODIPY‐TPA can act as an excellent hole transport layer in methylammonium lead triiodide (MAPbI 3 )‐based perovskite solar cells with measured power conversion efficiencies exceeding 17%, outperforming control solar cells with PEDOT:PSS by nearly 60%. Furthermore, the optical bandgap of 1.49 eV is shown to provide significant photodetection in the wavelength range of up to 800 nm where TPA‐azaBODIPY‐TPA functions as donor in near‐infrared organic photodetectors (OPDs) composed of fullerene derivatives. Overall, the established versatility of TPA‐azaBODIPY‐TPA, combined with its robust thermal stability as well as excellent solubility and processability, provides a new guide for developing highly efficient multi‐purpose electronic materials for the next‐generation of smart optoelectronic devices. image
Publisher: SPIE-Intl Soc Optical Eng
Date: 08-08-2014
Publisher: Wiley
Date: 12-01-2018
Publisher: Elsevier BV
Date: 02-2008
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: American Chemical Society (ACS)
Date: 27-06-2018
Publisher: Wiley
Date: 30-11-2020
Publisher: American Physical Society (APS)
Date: 19-10-2010
Publisher: Wiley
Date: 30-07-2010
Publisher: American Chemical Society (ACS)
Date: 21-06-2021
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.ULTRASMEDBIO.2019.10.015
Abstract: Knee arthroscopy is a minimally invasive surgery used in the treatment of intra-articular knee pathology which may cause unintended damage to femoral cartilage. An ultrasound (US)-guided autonomous robotic platform for knee arthroscopy can be envisioned to minimise these risks and possibly to improve surgical outcomes. The first necessary tool for reliable guidance during robotic surgeries was an automatic segmentation algorithm to outline the regions at risk. In this work, we studied the feasibility of using a state-of-the-art deep neural network (UNet) to automatically segment femoral cartilage imaged with dynamic volumetric US (at the refresh rate of 1 Hz), under simulated surgical conditions. Six volunteers were scanned which resulted in the extraction of 18278 2-D US images from 35 dynamic 3-D US scans, and these were manually labelled. The UNet was evaluated using a five-fold cross-validation with an average of 15531 training and 3124 testing labelled images per fold. An intra-observer study was performed to assess intra-observer variability due to inherent US physical properties. To account for this variability, a novel metric concept named Dice coefficient with boundary uncertainty (DSC
Publisher: IEEE
Date: 09-2007
Publisher: Wiley
Date: 28-10-2015
Publisher: Elsevier BV
Date: 06-2014
Publisher: AIP Publishing
Date: 09-03-2009
DOI: 10.1063/1.3098472
Abstract: Effects of different cathode metals, such as aluminum, calcium, and silver, and difference in their reflectivity on the photocurrent generation in pentacene-C60 heterojunction solar cell are presented. Using optical transfer matrix calculations, we find that metal reflectivity has a profound impact on the electrical field confinement within the multilayer device structures. Silver as cathode offers better optical-field confinement close to the pentacene-C60 interface over generally preferred aluminum cathode. External quantum efficiency measurements confirm higher exciton dissociation efficiency and high photocurrent generation ability of silver over aluminum cathode making the choice of cathode metal an important parameter in device optimization.
Publisher: Springer Science and Business Media LLC
Date: 29-07-2020
Publisher: IEEE
Date: 11-2017
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2020
Publisher: Royal Society of Chemistry (RSC)
Date: 31-07-2014
DOI: 10.1039/C4TC90093F
Publisher: Wiley
Date: 05-11-2007
Publisher: AIP Publishing
Date: 07-01-2013
DOI: 10.1063/1.4773556
Abstract: The effect of a zinc oxide optical spacer layer in broad-band polymer-fullerene solar cells is presented. The complimentary absorption in the donor and acceptor components allows photocurrent generation through photoinduced electron and hole-transfer mechanisms. Simulations of the optical-field distribution reveal that an optical spacer can be used to tune the spectral response to favor one photocurrent generation pathway via enhanced absorption in either the acceptor or donor component. Experimental results confirm these simulations, and the spacer is shown to enhance overall photocurrent in devices with thin active layers (& nm), with much less effect in thicker junctions (& nm).
Publisher: AIP Publishing
Date: 25-06-2007
DOI: 10.1063/1.2752540
Abstract: The authors implement and demonstrate in this letter a scheme that permits to drive electroluminescence with an extremely low turn-on voltage. The device behaves like compound semiconductors, in which the electroluminescence turn-on voltage is about the same as the open circuit voltage for the photovoltaic effect. However, the electroluminescence turn-on voltage is about half of the band gap of the emitting material that cannot be explained using current models of charge injection in organic semiconductors. The authors hereby propose explanation through an Auger-type two-step injection mechanism.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2021
Publisher: AIP Publishing
Date: 11-09-2006
DOI: 10.1063/1.2352800
Abstract: Solar cells exhibiting efficient photon harvesting are built from molecular blends of pentacene: PTCDI-C13H27. Absorption of the composition spans the whole visible spectrum with an onset at 730nm. External quantum efficiency approaches unity at the peak absorption of pentacene. A 2.0% power conversion efficiency is obtained under 80mWcm−2 AM 1.5 illumination, with 8.6mAcm−2 short-circuit current. The comparison with bilayer devices suggests directions of improvement in conversion efficiency such as controlled growth of the blend layers.
Publisher: Springer Science and Business Media LLC
Date: 17-11-2020
DOI: 10.1038/S41598-020-76962-X
Abstract: We successfully demonstrated a detailed and systematic enhancement of organic field effect transistors (OFETs) performance using dithienothiophene (DTT) and furan-flanked diketopyrrolopyrrole based donor–acceptor conjugated polymer semiconductor namely PDPPF-DTT as an active semiconductor. The self-assembled monolayers (SAMs) treatments at interface junctions of the semiconductor–dielectric and at the semiconductor–metal electrodes has been implemented using bottom gate bottom contact device geometry. Due to SAM treatment at the interface using tailored approach, the significant reduction of threshold voltage (V th ) from − 15.42 to + 5.74 V has been observed. In addition to tuning effect of V th , simultaneously charge carrier mobility (µ FET ) has been also enhanced the from 9.94 × 10 −4 cm 2 /Vs to 0.18 cm 2 /Vs. In order to calculate the trap density in each OFET device, the hysteresis in transfer characteristics has been studied in detail for bare and SAM treated devices. Higher trap density in Penta-fluoro-benzene-thiol (PFBT) treated OFET devices enhances the gate field, which in turn controls the charge carrier density in the channel, and hence gives lower V th = + 5.74 V. Also, PFBT treatment enhances the trapped interface electrons, which helps to enhance the mobility in this OFET architecture. The overall effect has led to possibility of reduction in the V th with simultaneous enhancements of µ FET in OFETs, following systematic device engineering methodology.
Publisher: Springer Science and Business Media LLC
Date: 14-01-2015
DOI: 10.1038/SREP07787
Publisher: Wiley
Date: 24-01-2012
Abstract: A facile one step method for periodic nanostructuring of organic solar cells is presented. The nanostructured metal-organic interface delivers combined enhanced light trapping and improved charge extraction leading to up to a 10% increase in power conversion efficiency of already optimized planar devices.
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2013
End Date: 2016
Funder: Australian Renewable Energy Agency, Australian Government
View Funded ActivityStart Date: 2017
End Date: 2020
Funder: Australia-India Strategic Research Fund
View Funded ActivityStart Date: 07-2021
End Date: 06-2024
Amount: $538,590.00
Funder: Australian Research Council
View Funded Activity