ORCID Profile
0000-0003-1875-9739
Current Organisation
University of New South Wales
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Photodetectors, Optical Sensors and Solar Cells | Electrical and Electronic Engineering | Condensed Matter Physics—Electronic And Magnetic Properties; | Nanotechnology | Optical Properties of Materials | Solid State Chemistry | Inorganic Chemistry | Ceramics | Alloy Materials | Aerospace Materials | Nanomanufacturing | Nanomaterials | Compound Semiconductors | Nanotechnology | Microtechnology | Materials Engineering |
Other | Solar-Photovoltaic Energy | Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering | Inorganic industrial chemicals | Solar-photoelectric | Medical instrumentation | Expanding Knowledge in Technology | "Stone, ceramics and clay materials" | Space Transport
Publisher: IEEE
Date: 06-2014
Publisher: Wiley
Date: 13-07-2016
DOI: 10.1002/PIP.2802
Publisher: American Physical Society (APS)
Date: 09-06-2016
Publisher: Springer Science and Business Media LLC
Date: 24-04-2018
DOI: 10.1038/S41598-018-24696-2
Abstract: A comprehensive assessment of the nature of the distribution of sub band-gap energy states in bulk GaAsBi is presented using power and temperature dependent photoluminescence spectroscopy. The observation of a characteristic red-blue-red shift in the peak luminescence energy indicates the presence of short-range alloy disorder in the material. A decrease in the carrier localisation energy demonstrates the strong excitation power dependence of localised state behaviour and is attributed to the filling of energy states furthest from the valence band edge. Analysis of the photoluminescence lineshape at low temperature presents strong evidence for a Gaussian distribution of localised states that extends from the valence band edge. Furthermore, a rate model is employed to understand the non-uniform thermal quenching of the photoluminescence and indicates the presence of two Gaussian-like distributions making up the density of localised states. These components are attributed to the presence of microscopic fluctuations in Bi content, due to short-range alloy disorder across the GaAsBi layer, and the formation of Bi related point defects, resulting from low temperature growth.
Publisher: SPIE
Date: 07-03-2014
DOI: 10.1117/12.2041289
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4822195
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4822196
Publisher: AIP
Date: 2013
DOI: 10.1063/1.4822193
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2EE22167E
Publisher: American Physical Society (APS)
Date: 06-12-2019
Publisher: Elsevier BV
Date: 03-2018
Publisher: Wiley
Date: 20-06-2012
DOI: 10.1002/PIP.2241
Publisher: The Optical Society
Date: 30-06-2011
DOI: 10.1364/OE.19.00A888
Publisher: Wiley
Date: 06-05-2022
DOI: 10.1002/PIP.3570
Abstract: Concentrated photovoltaic (CPV) systems can achieve high energy conversion efficiencies due to their use of concentrating optics and highly efficient solar cells however, power losses arising from the front surface reflection and metallization shading typically contribute a significant fraction to the total power loss for these devices. In flat silicon photovoltaic (PV) modules, the front‐metal finger shape is often shaped to minimize shading losses. Finger shape is even more relevant for CPV cells where the current density and front metal shading are much higher. This study compares the optical performance of five light management finger designs in CPV systems with two different refractive homogenizers. The optical efficiency and loss analysis were determined using ray‐tracing simulations. It is shown that shaped, light erting metal fingers can improve the optical efficiency in CPV systems by up to 9.9% absolute compared to rectangular fingers, corresponding to an absolute cell efficiency increase of 3.0%. Although sharp edged triangular finger structures may be challenging to fabricate, significant optical gains can still be achieved with trapezoid or rounded cap finger shapes.
Publisher: IEEE
Date: 06-2013
Publisher: Research Square Platform LLC
Date: 09-02-2022
DOI: 10.21203/RS.3.RS-1274090/V1
Abstract: Carrier loss mechanisms at microscopic regions is imperative for high-performance polycrystalline inorganic thin-film solar cells. Despite the progress on Kesterite, a promising environmental-benign and earth-abundant thin-film photovoltaic material, the microscopic carrier loss mechanisms and their impact on device performance remain unknown. Herein, we unveil these mechanisms in state-of-the-art Cu 2 ZnSnSe 4 (CZTSe) solar cells using a framework that links microscopic-structural and optoelectronic characterizations with three-dimensional device simulations. The results indicate the CZTSe films have an encouraging intragrain minority carrier lifetime of ns, a marginal radiative recombination loss through sub-band recombination and electrostatic potential fluctuation, whilst a large effective grain boundary recombination velocity of around 10 4 cm s -1 and a low net carrier density of ~1×10 15 cm -3 . We identify that severe grain boundary recombination and low net carrier density are the current limiting factors of device performance. The established framework can greatly advance the research of kesterite and other emerging photovoltaic materials.
Publisher: IEEE
Date: 06-2010
Publisher: Elsevier BV
Date: 04-2002
Publisher: Elsevier BV
Date: 2017
Publisher: International Solar Energy Society
Date: 2018
Publisher: Elsevier BV
Date: 02-2018
Publisher: AIP Publishing
Date: 27-09-2004
DOI: 10.1063/1.1794371
Abstract: Radiation-induced majority carrier removal is investigated from n+∕p− lattice-mismatched In0.56Ga0.44P solar cells under 1-MeV-electron irradiation. The change in carrier concentration in the 1×1017cm−3p− base layer is determined using standard capacitance–voltage techniques and found to proceed at a rate Rc=1.3cm−1, in agreement with that observed in lattice-matched InGaP. However, the observation of an increased short-circuit current and short-wavelength quantum efficiency over the unirradiated values at electron fluence levels in excess of 3×1015cm−2, allows the carrier concentration from the n+ emitter layer to be measured. By modeling the quantum efficiency of these solar cells, it is shown that the main photoresponse from these lattice-mismatched solar cells is due to drift transport, making the spectral response highly sensitive to changes in the width of the depletion region. Using this technique, the carrier concentration in the 2×1018cm−3 n+ emitter layer is found to be reduced to 1×1018cm−3 after exposure to an electron fluence of 3×1015cm−2.
Publisher: Elsevier
Date: 2006
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2016
Publisher: Wiley
Date: 14-11-2019
DOI: 10.1002/PIP.3202
Publisher: IEEE
Date: 06-2011
Publisher: Wiley
Date: 26-08-2010
DOI: 10.1002/PIP.1024
Publisher: American Chemical Society (ACS)
Date: 09-05-2022
Publisher: IEEE
Date: 06-2011
Publisher: SPIE
Date: 15-05-2014
DOI: 10.1117/12.2052286
Publisher: AIP Publishing
Date: 27-12-1999
DOI: 10.1063/1.125580
Abstract: A strain-balance multiquantum well (MQW) approach to enhance the GaAs solar cell efficiency is reported. Using a p-i-n diode structure, the strain-balanced GaAsP/InGaAs MQW is grown on a GaAs substrate and equals a good GaAs cell in terms of power conversion efficiency. The cell design is presented together with measurements of the forward bias dark current density, quantum efficiency, and 3000 K light-IV response. Cell efficiencies under standard air mass (AM) 1.5 and AM 0 illumination are projected from experimental data and the suitability of this cell for enhancing GaInP/GaAs tandem cell efficiencies is discussed.
Publisher: American Chemical Society (ACS)
Date: 25-05-2010
DOI: 10.1021/JZ100566U
Publisher: IEEE
Date: 05-2011
Publisher: Springer Science and Business Media LLC
Date: 07-2009
Publisher: Springer Science and Business Media LLC
Date: 07-10-2013
DOI: 10.1038/SREP02874
Abstract: We illustrate the important trade-off between far-field scattering effects, which have the potential to provide increased optical path length over broad bands and parasitic absorption due to the excitation of localized surface plasmon resonances in metal nanoparticle arrays. Via detailed comparison of photocurrent enhancements given by Au, Ag and Al nanostructures on thin-film GaAs devices we reveal that parasitic losses can be mitigated through a careful choice of scattering medium. Absorption at the plasmon resonance in Au and Ag structures occurs in the visible spectrum, impairing device performance. In contrast, exploiting Al nanoparticle arrays results in a blue shift of the resonance, enabling the first demonstration of truly broadband plasmon enhanced photocurrent and a 22% integrated efficiency enhancement.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Publisher: Elsevier BV
Date: 04-2002
Publisher: American Physical Society (APS)
Date: 21-10-2005
Publisher: Author(s)
Date: 2018
DOI: 10.1063/1.5053511
Publisher: IEEE
Date: 06-2018
Publisher: AIP Publishing
Date: 11-08-2008
DOI: 10.1063/1.2970157
Abstract: Molecular materials may overcome some of the difficulties for making an intermediate band solar cell by storing energy in long-lived triplet states. Both the problems of fast nonradiative interband relaxation and selective photon absorption can be solved by this approach. A practical implementation of the molecular intermediate band solar cell is considered with a symmetric band alignment, resting on a proven triplet-triplet annihilation process. The limiting power conversion efficiency for this system exceeds that of a single bandgap device over a broad range, peaking at 40.6% for 1.9eV under 1 sun illumination.
Publisher: Royal Society of Chemistry (RSC)
Date: 2010
DOI: 10.1039/B913243K
Abstract: Photochemical upconversion is performed, whereby emitter triplet states are produced through triplet energy transfer from sensitizer molecules excited with low energy photons. The triplet emitter molecules undergo triplet-triplet annihilation to yield excited singlet states which emit upconverted fluorescence. Experiments comparing the 560 nm prompt fluorescence when rubrene emitter molecules are excited directly, using 525 nm laser pulses, to the delayed, upconverted fluorescence when the porphyrin sensitizer molecules are excited with 670 nm laser pulses reveal annihilation efficiencies to produce excited singlet emitters in excess of 20%. Conservative measurements reveal a 25% annihilation efficiency, while a direct comparison between the prompt and delayed fluorescence yield suggests a value as high as 33%. Due to fluorescence quenching, the photon upconversion efficiencies are lower, at 16%.
Publisher: IEEE
Date: 2006
Publisher: IEEE
Date: 06-2018
Publisher: IOP Publishing
Date: 11-06-2013
Publisher: IEEE
Date: 06-2016
Publisher: Wiley
Date: 27-05-2013
DOI: 10.1002/PIP.2376
Publisher: Springer Science and Business Media LLC
Date: 15-07-2019
Publisher: IEEE
Date: 05-2008
Publisher: AIP Publishing
Date: 23-06-2021
DOI: 10.1063/5.0048653
Abstract: In order to realize a clean energy society by using renewable energies, high-performance solar cells are a very attractive proposition. The development of high-performance solar cells offers a promising pathway toward achieving high power per unit cost for many applications. As state-of-the-art of single-junction solar cells are approaching the Shockley–Queisser limit of 32%–33%, an important strategy to raise the efficiency of solar cells further is stacking solar cell materials with different bandgaps to absorb different colors of the solar spectrum. The III–V semiconductor materials provide a relatively convenient system for fabricating multi-junction solar cells providing semiconductor materials that effectively span the solar spectrum as demonstrated by world record efficiencies (39.2% under one-sun and 47.1% under concentration) for six-junction solar cells. This success has inspired attempts to achieve the same with other materials like perovskites for which lower manufacturing costs may be achieved. Recently, Si multi-junction solar cells such as III–V/Si, II–VI/Si, chalcopyrite/Si, and perovskite/Si have become popular and are getting closer to economic competitiveness. Here, we discuss the perspectives of multi-junction solar cells from the viewpoint of efficiency and low-cost potential based on scientific and technological arguments and possible market applications. In addition, this article provides a brief overview of recent developments with respect to III–V multi-junction solar cells, III–V/Si, II–VI/Si, perovskite/Si tandem solar cells, and some new ideas including so-called 3rd generation concepts.
Publisher: IOP Publishing
Date: 04-07-2017
Publisher: American Physical Society (APS)
Date: 24-10-2019
Publisher: AIP Publishing
Date: 25-06-2012
DOI: 10.1063/1.4731277
Abstract: In this paper, we propose an innovative concept for solar power conversion—the “photon ratchet” intermediate band solar cell (IBSC)—which may increase the photovoltaic energy conversion efficiency of IBSCs by increasing the lifetime of charge carriers in the intermediate state. The limiting efficiency calculation for this concept shows that the efficiency can be increased by introducing a fast thermal transition of carriers into a non-emissive state. At 1 sun, the introduction of a “ratchet band” results in an increase of efficiency from 46.8% to 48.5%, due to suppression of entropy generation.
Publisher: OSA
Date: 2019
Publisher: Elsevier BV
Date: 05-2019
Publisher: Elsevier BV
Date: 12-2017
Publisher: IEEE
Date: 20-06-2021
Publisher: IOP Publishing
Date: 05-2019
Publisher: SPIE
Date: 19-08-2010
DOI: 10.1117/12.862739
Publisher: IEEE
Date: 2006
Publisher: Elsevier BV
Date: 05-2005
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/CH12117
Abstract: Photochemical upconversion is applied to a hydrogenated amorphous silicon solar cell in the presence of a back-scattering layer. A custom-synthesized porphyrin was utilized as the sensitizer species, with rubrene as the emitter. Under a bias of 24 suns, a peak external quantum efficiency (EQE) enhancement of ~2 % was observed at a wavelength of 720 nm. Without the scattering layer, the EQE enhancement was half this value, indicating that the effect of the back-scatterer is to double the efficacy of the upconverting device. The results represent an upconversion figure of merit of 3.5 × 10–4 mA cm–2 sun–2, which is the highest reported to date.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2019
Publisher: IEEE
Date: 2006
Publisher: IOP Publishing
Date: 2017
Publisher: IEEE
Date: 06-2018
Publisher: Wiley
Date: 02-02-2012
DOI: 10.1002/PIP.2159
Publisher: Wiley
Date: 19-01-2011
DOI: 10.1002/PIP.1069
Publisher: Elsevier BV
Date: 09-2019
Publisher: American Chemical Society (ACS)
Date: 09-09-2014
DOI: 10.1021/PH5001567
Publisher: SPIE
Date: 09-09-2019
DOI: 10.1117/12.2526849
Publisher: IEEE
Date: 06-2013
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2014
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2018
Publisher: Elsevier BV
Date: 09-2011
Publisher: CRC Press
Date: 18-01-2018
Publisher: IEEE
Date: 2006
Publisher: SPIE
Date: 03-03-2020
DOI: 10.1117/12.2550136
Publisher: IEEE
Date: 06-2019
Publisher: IEEE
Date: 06-2013
Publisher: IEEE
Date: 06-2018
Publisher: IEEE
Date: 06-2016
Publisher: AIP Publishing
Date: 22-04-2013
DOI: 10.1063/1.4803459
Abstract: We report the effects of the deposition of an AlAs cap layer (CL) over InAs quantum dots (QDs) on the performance of QD solar cells (QDSCs). The growth of AlAs CL over InAs QDs led to the elimination of the wetting layer absorption and hence the enhancement of the open-current voltage, Voc, of a 20-layer InAs/GaAs QDSC from 0.69 V to 0.79 V. Despite a slight reduction in short-circuit current, Jsc, for the QDSC with AlAs CL, the enhancement of the Voc is enough to ensure that its efficiency is higher than the QDSC without AlAs CL.
Publisher: Springer Science and Business Media LLC
Date: 2000
Publisher: IEEE
Date: 06-2018
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C4EE03132F
Abstract: Organic photovoltaics are analysed for use within a photovoltaic greenhouse for combined crop growth and electricity production.
Publisher: AIP Publishing
Date: 25-08-2014
DOI: 10.1063/1.4894424
Abstract: Quantum wires (QWRs) form naturally when growing strain balanced InGaAs/GaAsP multi-quantum wells (MQW) on GaAs [100] 6° misoriented substrates under the usual growth conditions. The presence of wires instead of wells could have several unexpected consequences for the performance of the MQW solar cells, both positive and negative, that need to be assessed to achieve high conversion efficiencies. In this letter, we study QWR properties from the point of view of their performance as solar cells by means of transmission electron microscopy, time resolved photoluminescence and external quantum efficiency (EQE) using polarised light. We find that these QWRs have longer lifetimes than nominally identical QWs grown on exact [100] GaAs substrates, of up to 1 μs, at any level of illumination. We attribute this effect to an asymmetric carrier escape from the nanostructures leading to a strong 1D-photo-charging, keeping electrons confined along the wire and holes in the barriers. In principle, these extended lifetimes could be exploited to enhance carrier collection and reduce dark current losses. Light absorption by these QWRs is 1.6 times weaker than QWs, as revealed by EQE measurements, which emphasises the need for more layers of nanostructures or the use light trapping techniques. Contrary to what we expected, QWR show very low absorption anisotropy, only 3.5%, which was the main drawback a priori of this nanostructure. We attribute this to a reduced lateral confinement inside the wires. These results encourage further study and optimization of QWRs for high efficiency solar cells.
Publisher: IEEE
Date: 06-2016
Publisher: American Chemical Society (ACS)
Date: 25-01-2011
DOI: 10.1021/JP108839G
Abstract: Conventional photochemical upconversion (UC) through homo-geneous triplet-triplet annihilation (TTA) is subject to several enthalpic losses that limit the UC margin. Here, we address one of these losses: the triplet energy transfer (TET) from the sensitizer to the emitter molecules. Usually, the triplet energy level of the emitter is set below that of the sensitizer. In our system, the triplet energy level of the emitter exceeds that of the sensitizer by ∼600 cm(-1). Choosing suitable concentrations for the sensitizer and emitter molecules, we can exploit entropy as a driving force for the migration of triplet excitation from the sensitizer to the emitter manifolds. Thereby we obtain a new record for the peak-to-peak TTA-UC energy margin of 0.94 eV. A modified Stern-Volmer analysis yields a TET rate constant of 2.0 × 10(7) M(-1) s(-1). Despite being relatively inefficient, the upconverted fluorescence is easily visible to the naked eye with irradiation intensities as low as 2 W cm(-2).
Publisher: IOP Publishing
Date: 24-05-2016
Publisher: IEEE
Date: 2005
Publisher: Elsevier BV
Date: 10-2019
Publisher: SPIE
Date: 16-03-2015
DOI: 10.1117/12.2077573
Publisher: IEEE
Date: 06-2017
Publisher: IEEE
Date: 06-2019
Publisher: SPIE
Date: 25-03-2013
DOI: 10.1117/12.2005332
Publisher: Elsevier BV
Date: 10-2017
Publisher: IOP Publishing
Date: 16-11-2017
Publisher: IEEE
Date: 06-2010
Publisher: AIP Publishing
Date: 18-03-2003
DOI: 10.1063/1.1561159
Abstract: Anti-Stokes emission is observed experimentally from a series of quantum well p–i–n structures and is attributed to a quasithermal equilibrium being established between the quantum well and barrier material. A device is described whereby the anti-Stokes emission from a quantum well p–i–n structure can be used to increase the short-circuit current of a second conventional solar cell, essentially coupling sub-band-gap sunlight to the ambient thermal reservoir. For a GaAs p/n cell at 300 K, this effect is calculated to raise the one-sun power conversion efficiency from 30.0% to 31.3%. Greater efficiency increases are possible if a thermal gradient is established across the structure.
Publisher: Wiley
Date: 11-04-2015
DOI: 10.1002/PIP.2615
Publisher: IEEE
Date: 2005
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 04-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SE00276F
Abstract: Strain-balanced GaInAs/GaAsP quantum wells were incorporated into the classical GaInP/GaAs tandem photoelectrochemical water splitting device to increase the range of photon absorption and achieve higher solar-to-hydrogen efficiencies.
Publisher: IEEE
Date: 06-2012
Publisher: IEEE
Date: 06-2016
Publisher: IEEE
Date: 14-06-2020
Publisher: Springer Science and Business Media LLC
Date: 19-06-2017
DOI: 10.1557/ADV.2017.448
Publisher: IEEE
Date: 06-2011
Publisher: AIP Publishing
Date: 09-06-2014
DOI: 10.1063/1.4883648
Abstract: An unambiguous observation of hot-carrier photocurrent from an InGaAs single quantum well solar cell is reported. Simultaneous photo-current and photoluminescence measurements were performed for incident power density 0.04–3 kW cm−2, lattice temperature 10 K, and forward bias 1.2 V. An order of magnitude photocurrent increase was observed for non-equilibrium hot-carrier temperatures & K. This photocurrent activation temperature is consistent with that of equilibrium carriers in a lattice at elevated temperature. The observed hot-carrier photo-current is extracted from the well over an energy selective GaAs barrier, thus integrating two essential components of a hot-carrier solar cell: a hot-carrier absorber and an energy selective contact.
Publisher: Elsevier BV
Date: 03-2019
Publisher: American Chemical Society (ACS)
Date: 16-12-2011
DOI: 10.1021/JA210029W
Abstract: We study the appearance and energy of the charge transfer (CT) state using measurements of electroluminescence (EL) and photoluminescence (PL) in blend films of high-performance polymers with fullerene acceptors. EL spectroscopy provides a direct probe of the energy of the interfacial states without the need to rely on the LUMO and HOMO energies as estimated in pristine materials. For each polymer, we use different fullerenes with varying LUMO levels as electron acceptors, in order to vary the energy of the CT state relative to the blend with [6,6]-phenyl C61-butyric acid methyl ester (PCBM). As the energy of the CT state emission approaches the absorption onset of the blend component with the smaller optical bandgap, E(opt,min) ≡ min{E(opt,donor) E(opt,acceptor)}, we observe a transition in the EL spectrum from CT emission to singlet emission from the component with the smaller bandgap. The appearance of component singlet emission coincides with reduced photocurrent and fill factor. We conclude that the open circuit voltage V(OC) is limited by the smaller bandgap of the two blend components. From the losses of the studied materials, we derive an empirical limit for the open circuit voltage: V(OC) ≲ E(opt,min)/e - (0.66 ± 0.08)eV.
Publisher: Materials Research Society
Date: 2008
Publisher: Wiley
Date: 24-03-2016
DOI: 10.1002/PIP.2769
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9EE01726G
Abstract: Cd-Free CZTS solar cell with above 10% efficiency was achieved by an Al 2 O 3 passivation layer prepared by ALD.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2017
Publisher: IEEE
Date: 06-2016
Publisher: IEEE
Date: 14-06-2020
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4EE00646A
Abstract: We assess the net carbon emissions during a transition to photovoltaic power generation, comparing established and emerging thin-film PV technologies.
Publisher: Author(s)
Date: 2016
DOI: 10.1063/1.4962096
Publisher: SPIE
Date: 14-03-2016
DOI: 10.1117/12.2217590
Publisher: Elsevier BV
Date: 04-2019
Publisher: Elsevier BV
Date: 2018
Publisher: IEEE
Date: 06-2019
Publisher: IMPERIAL COLLEGE PRESS
Date: 16-10-2014
Publisher: IEEE
Date: 06-2014
Publisher: IEEE
Date: 06-2016
Publisher: Elsevier BV
Date: 04-2006
Publisher: American Physical Society (APS)
Date: 18-07-2012
Publisher: Wiley
Date: 10-02-2016
DOI: 10.1002/PIP.2751
Publisher: River Publishers
Date: 2016
Publisher: IEEE
Date: 06-2011
Publisher: IEEE
Date: 06-2015
Publisher: AIP Publishing
Date: 15-12-1997
DOI: 10.1063/1.366510
Abstract: We have measured electroluminescence (EL) spectra of GaAs/InGaAs and AlGaAs/GaAs single quantum well (QW) p-i-n photodiodes at temperatures between 200 and 300 K and forward biases close to the open circuit voltage. Integrated EL spectra vary like eqV/nkT with an ideality factor n=1.05±0.05 over five decades, indicating purely radiative processes. The spectra are calibrated into absolute units enabling comparison to be made with the predictions of a theoretical model. For each temperature and bias we calculate the EL spectrum and radiative current expected in the detailed balance limit, integrating the theoretical emission spectrum over the surface of the device, in order to establish the quasi-Fermi potential separation, Δφf, in the QW and, where possible, in the host material. For the GaAs/InGaAs cell we are able to model emission from the QW and the host material simultaneously. We find that, in all cases, the QW emission is overestimated by theory if it is assumed that Δφf=V. QW emission corresponds instead to a value of Δφf which a few tens of mV less than V. In contrast, emission from the host material, where visible, is well fitted by the model with Δφf=V at all biases and temperatures. We attribute the variation in Δφf to irreversible thermally assisted escape from the QWs.
Publisher: Elsevier BV
Date: 07-2005
Publisher: AIP Publishing
Date: 12-04-2021
DOI: 10.1063/5.0049120
Abstract: Multiple exciton generation (MEG) increases the short circuit current of solar cells and is, therefore, often cited as a candidate scheme for surpassing the efficiency limit of single junction solar cells. Conventionally, limiting efficiencies for MEG solar cells have been calculated using quasi-equilibrium models that implicitly assume an effective separation of timescales between different processes. We show here that this separation of timescales is not possible for MEG solar cells, with Auger recombination, the inverse process to multi-exciton generation, needing to be considered explicitly in the efficiency limits of an MEG solar cell. We assess the impact of Auger recombination using a non-equilibrium model of a quantum dot solar cell that satisfies microscopic reversibility and can approximate experimental external quantum efficiency (EQE) curves of MEG solar cells. Recombination—both Auger and radiative—is treated in a quasi-equilibrium approach, which can be justified with a clear model for the separation of timescales. A key insight of this model is that the achievable voltage of the device, and hence the solar energy conversion efficiency, depends on the absolute values of the impact ionization rate and the rate at which electrons lose energy through phonon scattering. By contrast, the EQE profile at short circuit depends only on the ratio of these two rates. This shows that the potential of certain MEG solar cell approaches cannot be assessed from EQE improvements alone, which highlights the importance of considering non-equilibrium processes in models of solar energy conversion devices.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2014
Publisher: Elsevier BV
Date: 09-2017
Publisher: IEEE
Date: 06-2014
Publisher: IEEE
Date: 14-06-2020
Publisher: American Chemical Society (ACS)
Date: 06-10-2021
Publisher: SPIE
Date: 10-02-2011
DOI: 10.1117/12.875757
Publisher: Springer Science and Business Media LLC
Date: 03-2021
DOI: 10.1038/S42005-021-00543-1
Abstract: A detailed balance calculation reveals an extremely high efficiency of 63.2% for intermediate-band solar cells (IBSCs) under maximum sunlight concentration. However, an actual IBSC device with an efficiency larger than the Shockley-Queisser (SQ) limit has so far not been reported. The main difficulties lie in realizing an efficient sequential two-photon absorption (STPA) which requires a sufficiently long lifetime intermediate state or intermediate band. In this article, we propose the concept of a ratchet type IBSC, utilizing a long lifetime of rare-earth ion luminescence centers in Erbium-doped GaAs. The temperature dependent differential external quantum efficiency reveals a significant STPA contribution originating from the Er 3+ luminescence center. All the results were modeled and interpreted by integrating the ratchet effect with up-conversion along with a density functional theory (DFT) simulation. Our work demonstrates that the long lifetime energy-transfer mechanism in Er 3+ centers contributes directly to the formation of a ratchet type IB.
Publisher: AIP Publishing
Date: 11-2005
DOI: 10.1063/1.2115095
Abstract: Presented in this paper are 1 MeV electron irradiation effects on wide-band-gap (1.97 eV) (Al0.08Ga0.92)0.52In0.48P diodes and solar cells. The carrier removal rate estimated in p-AlInGaP with electron fluence is about 1cm−1, which is lower than that in InP and GaAs. From high-temperature deep-level transient spectroscopy measurements, a deep-level defect center such as majority-carrier (hole) trap H2 (Eν+0.90±0.05eV) was observed. The changes in carrier concentrations (Δp) and trap densities as a function of electron fluence were compared, and as a result the total introduction rate, 0.39cm−1, of majority-carrier trap centers (H1 and H2) is different from the carrier removal rate, 1cm−1, in p-AlInGaP. From the minority-carrier injection annealing (100mA∕cm2), the annealing activation energy of H2 defect is ΔE=0.60eV, which is likely to be associated with a vacancy-phosphorus Frenkel pair (Vp-Pi). The recovery of defect concentration and carrier concentration in the irradiated p-AlInGaP by injection relates that a deep-level defect H2 acts as a recombination center as well as compensator center.
Publisher: IEEE
Date: 2005
Publisher: AIP Publishing
Date: 15-12-2010
DOI: 10.1063/1.3517826
Abstract: A master equation approach to the limiting efficiencies of solar cells with molecular absorbers is presented. A number of model absorbers are analyzed that possess identical absorption spectra, but with differing numbers of electronic excited states. The Shockley–Queisser limit is reproduced for a molecule resembling a semiconductor, with an infinity of electronic levels in the excited state manifold. However, when only a few electronic states contribute to the absorption spectrum, the limiting efficiency is reduced. In the extreme case, where only a single electronic excited state participates in the absorption spectrum, the efficiency limit is 28.9%. At high energy thresholds, built-in thermal up-conversion results in solar cells with efficiencies exceeding the Shockley–Queisser curve. The analysis is applicable to any single threshold photovoltaic device, including those based on semiconductor, polymer, and small molecule absorbers.
Publisher: IEEE
Date: 06-2015
Publisher: Author(s)
Date: 2016
DOI: 10.1063/1.4962072
Publisher: Springer Science and Business Media LLC
Date: 23-07-2018
Publisher: American Physical Society (APS)
Date: 16-03-2023
Publisher: IOP Publishing
Date: 09-2009
Publisher: AIP Publishing
Date: 12-09-2011
DOI: 10.1063/1.3636401
Abstract: The hot-carrier solar cell (HC-SC) is an ambitious approach to solar energy conversion which in principle can achieve high efficiency (84%) from a single bandgap semiconductor. Here we propose a method of utilising hot-carriers within a photovoltaic device in which energy is extracted optically from a hot-carrier distribution rather than through the usual approach of electrical conduction. Depending on the optical extraction rate, the concept proposed here may attain an upper efficiency approaching that of the conventional HC-SC.
Publisher: Elsevier BV
Date: 05-2016
Publisher: IEEE
Date: 06-2016
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3RA46953K
Abstract: Direct observation of triplet energy transfer from sensitiser to emitter is modelled and provides comprehensive description of bimolecular upconversion.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2012
Publisher: IEEE
Date: 06-2011
Publisher: IEEE
Date: 06-2011
Publisher: AIP Publishing
Date: 15-06-2005
DOI: 10.1063/1.1946908
Abstract: The effect of increasing the number of quantum wells in a strain-compensated, multiquantum-well solar cell is investigated. It is found that as the well number is increased, dark current level close to the operating point rises linearly. Short-circuit current in the AM0 spectrum also rises linearly with the inclusion of more quantum wells. This allows the cell to maintain a constant open-circuit voltage irrespective of the number of wells grown. This is anticipated to have advantages when the cell is used as a replacement for the GaAs junction in the existing generation of tandem and triple-junction cells since current levels can be matched to the upper junction without detriment to the voltage performance. This result allows us to predict a tandem cell AM0 efficiency of 23.8% based on the 50-well cell.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2EE21136J
Publisher: AIP Publishing
Date: 29-11-2004
DOI: 10.1063/1.1829136
Abstract: We present here the direct observation of the majority and minority carrier defects generation from wide-band-gap (2.04eV) and thick (2μm) p-AlInGaP diodes and solar cells structures before and after 1MeV electron irradiation by deep level transient spectroscopy (DLTS). One dominant hole-emitting trap H1 (EV+0.37±0.05eV) and two electron-emitting traps, E1 (EC−0.22±0.04eV) and E3 (EC−0.78±0.05eV) have been observed in the temperature range, which we could scan by DLTS. Detailed analysis of the minority carrier injection annealing experiment reveals that the H1 center has shown the same annealing characteristics, which has been previously observed in all phosphide-based materials such as InP, InGaP, and InGaAsP. The annealing property of the radiation-induced defects in p-AlInGaP reveals that multijunction solar cells and other optoelectronic devices such as light-emitting diodes based on this material could be considerably better to Si and GaAs in a radiation environment.
Publisher: OSA
Date: 2011
Publisher: IEEE
Date: 05-2006
Publisher: Elsevier BV
Date: 11-2006
Publisher: Wiley
Date: 2005
DOI: 10.1002/PIP.643
Publisher: SPIE-Intl Soc Optical Eng
Date: 2008
Publisher: IEEE
Date: 06-2013
Publisher: SPIE
Date: 11-02-2010
DOI: 10.1117/12.844114
Publisher: Elsevier BV
Date: 11-2006
Publisher: Wiley
Date: 26-12-2018
DOI: 10.1002/PIP.3099
Publisher: IOP Publishing
Date: 22-06-2015
Publisher: Elsevier BV
Date: 11-2008
Publisher: SPIE
Date: 19-08-2010
DOI: 10.1117/12.860681
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2019
Publisher: IEEE
Date: 06-2012
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2016
Publisher: Elsevier BV
Date: 02-2005
Publisher: SPIE
Date: 09-02-2012
DOI: 10.1117/12.910581
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2016
Publisher: Wiley
Date: 05-05-2021
DOI: 10.1002/PIP.3405
Abstract: The economic value of a photovoltaic installation depends upon both its lifespan and power conversion efficiency. Progress toward the latter includes mechanisms to circumvent the Shockley‐Queisser limit, such as tandem designs and multiple exciton generation (MEG). Here we explain how both silicon tandem and MEG‐enhanced silicon cell architectures result in lower cell operating temperatures, increasing the device lifetime compared to standard c‐Si cells. Also demonstrated are further advantages from MEG enhanced silicon cells: (i) the device architecture can completely circumvent the need for current‐matching and (ii) upon degradation, tetracene, a candidate singlet fission (a form of MEG) material, is transparent to the solar spectrum. The combination of (i) and (ii) mean that the primary silicon device will continue to operate with reasonable efficiency even if the singlet fission layer degrades. The lifespan advantages of singlet fission enhanced silicon cells, from a module perspective, are compared favorably alongside the highly regarded perovskite/silicon tandem and conventional c‐Si modules.
Publisher: Elsevier BV
Date: 02-2003
Publisher: Elsevier BV
Date: 04-2001
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2014
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 11-2016
Publisher: IEEE
Date: 20-06-2021
Publisher: Elsevier BV
Date: 04-2002
Publisher: Elsevier BV
Date: 2003
Publisher: Springer Science and Business Media LLC
Date: 08-03-2018
DOI: 10.1038/S42005-018-0007-6
Abstract: Conventional solar cell efficiencies are capped by the ~31% Shockley–Queisser limit because, even with an optimally chosen bandgap, some red photons will go unabsorbed and the excess energy of the blue photons is wasted as heat. Here we demonstrate a “quantum ratchet” device that avoids this limitation by inserting a pair of linked states that form a metastable photoelectron trap in the bandgap. It is designed both to reduce non-radiative recombination, and to break the Shockley–Queisser limit by introducing an additional “sequential two photon absorption” (STPA) excitation channel across the bandgap. We realise the quantum ratchet concept with a semiconductor nanostructure. It raises the electron lifetime in the metastable trap by ~10 4 , and gives a STPA channel that increases the photocurrent by a factor of ~50%. This result illustrates a new paradigm for designing ultra-efficient photovoltaic devices.
Publisher: IEEE
Date: 06-2017
Publisher: Elsevier BV
Date: 05-2016
Publisher: Wiley
Date: 20-01-2015
DOI: 10.1002/PIP.2585
Publisher: Elsevier BV
Date: 06-2009
Publisher: Wiley
Date: 13-12-2020
Publisher: Elsevier BV
Date: 11-2016
Publisher: SPIE
Date: 29-04-2016
DOI: 10.1117/12.2228589
Publisher: MDPI AG
Date: 28-01-2020
DOI: 10.3390/APP10030871
Abstract: In this study, a novel configuration for luminescent solar concentrator photovoltaic (LSC PV) devices is presented, with vertically placed bifacial PV solar cells made of mono-crystalline silicon (mono c-Si). This LSC PV device comprises multiple rectangular cuboid lightguides, made of poly (methyl methacrylate) (PMMA), containing Lumogen dyes, in particular, either Lumogen red 305 or orange 240. The bifacial solar cells are located in between these lightguide cubes and can, therefore, receive irradiance at both of their surfaces. The main aim of this study is to theoretically determine the power conversion efficiency (PCE) of five differently configured LSC PV devices. For this purpose, Monte Carlo ray tracing simulations were executed to analyze the irradiance at receiving PV cell surfaces, as well as the optical performance of these LSC PV devices. Five different LSC PV devices, with different geometries and varying dye concentrations, were modeled. To maximize the device efficiency, the bifacial cells were also attached to the back side of the lightguides. The ray tracing simulations resulted in a maximum efficiency of 16.9% under standard test conditions (STC) for a 15 × 15 cm2 LSC PV device, consisting of nine rectangular cuboid 5 × 5 × 1 cm3 PMMA lightguides with 5 ppm orange 240 dye, with 12 vertically positioned 5 × 1 cm2 bifacial cells in between the lightguides and nine 5 × 5 cm2 PV cells attached to the back of the device. If the cells are not applied to the back of this LSC PV device configuration, the maximum PCE will be 2.9% (under STC), where the LSC PV device consists of 25 cubical 1 × 1 × 1 cm3 PMMA lightguides with 110 ppm red 305 dye and 40 vertically oriented bifacial PV cells of 1 × 1 cm2 in between the lightguides. These results show the vast future potential for LSC PV technologies, with a higher performance and efficiency than the common threshold PCE for LSC PV devices of 10%.
Publisher: Springer Science and Business Media LLC
Date: 12-04-2018
Publisher: Informa UK Limited
Date: 10-11-2015
Publisher: IOP Publishing
Date: 29-06-2007
DOI: 10.1143/JJAP.46.L645
Publisher: Elsevier BV
Date: 08-2017
Publisher: IEEE
Date: 2000
Publisher: IEEE
Date: 06-2009
Publisher: Elsevier BV
Date: 04-2006
Publisher: American Chemical Society (ACS)
Date: 08-04-2011
DOI: 10.1021/JZ200270W
Publisher: Pleiades Publishing Ltd
Date: 08-2004
DOI: 10.1134/1.1787111
Publisher: SPIE
Date: 09-02-2012
DOI: 10.1117/12.909324
Publisher: IEEE
Date: 05-2008
Publisher: IEEE
Date: 2000
Publisher: Elsevier BV
Date: 12-2016
Publisher: Wiley
Date: 02-06-2011
DOI: 10.1002/PIP.1121
Publisher: American Chemical Society (ACS)
Date: 18-04-2002
DOI: 10.1021/CG025502Y
Publisher: Elsevier BV
Date: 11-2018
Publisher: AIP Publishing
Date: 06-2015
DOI: 10.1063/1.4916561
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2022
Publisher: Springer Science and Business Media LLC
Date: 03-2005
Publisher: Wiley
Date: 18-02-2005
DOI: 10.1002/PIP.606
Publisher: Springer Science and Business Media LLC
Date: 21-07-2022
DOI: 10.1038/S41560-022-01078-7
Abstract: Understanding carrier loss mechanisms at microscopic regions is imperative for the development of high-performance polycrystalline inorganic thin-film solar cells. Despite the progress achieved for kesterite, a promising environmentally benign and earth-abundant thin-film photovoltaic material, the microscopic carrier loss mechanisms and their impact on device performance remain largely unknown. Herein, we unveil these mechanisms in state-of-the-art Cu 2 ZnSnSe 4 (CZTSe) solar cells using a framework that integrates multiple microscopic and macroscopic characterizations with three-dimensional device simulations. The results indicate the CZTSe films have a relatively long intragrain electron lifetime of 10–30 ns and small recombination losses through bandgap and/or electrostatic potential fluctuations. We identify that the effective minority carrier lifetime of CZTSe is dominated by a large grain boundary recombination velocity (~10 4 cm s −1 ), which is the major limiting factor of present device performance. These findings and the framework can greatly advance the research of kesterite and other emerging photovoltaic materials.
Start Date: 2022
End Date: 12-2024
Amount: $410,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 12-2022
End Date: 12-2025
Amount: $460,485.00
Funder: Australian Research Council
View Funded ActivityStart Date: 09-2007
End Date: 09-2008
Amount: $280,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 11-2022
End Date: 11-2025
Amount: $437,060.00
Funder: Australian Research Council
View Funded ActivityStart Date: 2023
End Date: 12-2023
Amount: $480,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2006
End Date: 06-2007
Amount: $1,200,000.00
Funder: Australian Research Council
View Funded Activity