Publications
293 results found
Lumb MP, Gonzalez M, Bailey CG, et al., 2013, Drift-diffusion modeling of InP-based triple junction solar cells, Conference on Physics, Simulation, and Photonic Engineering of Photovoltaic Devices II, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 10
Ekins-Daukes NJ, 2013, Routes to High Efficiency Photovoltaic Power Conversion, 39th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 13-16, ISSN: 0160-8371
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- Citations: 5
Richards R, Bastiman F, Hunter CJ, et al., 2013, GaAsBi MQWs for Multi-Junction Photovoltaics, 39th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 303-305, ISSN: 0160-8371
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- Citations: 5
Fuehrer M, Farrell D, Ekins-Daukes N, 2013, CPV Modelling With <i>Solcore</i>: An Extensible Modelling Framework For The Rapid Computational Simulation And Evaluation Of Solar Cell Designs And Concepts, 9th International Conference on Concentrator Photovoltaic Systems (CPV), Publisher: AMER INST PHYSICS, Pages: 34-37, ISSN: 0094-243X
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- Citations: 6
Lee K-H, Barnham KWJ, Roberts JS, et al., 2013, Dual-Junction Solar Cells With Multiple-Quantum-Well Top Cells, 9th International Conference on Concentrator Photovoltaic Systems (CPV), Publisher: AMER INST PHYSICS, Pages: 45-47, ISSN: 0094-243X
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- Citations: 2
Hylton NP, Li X, Giannini V, et al., 2013, Al Nanoparticle Arrays for Broadband Absorption Enhancements in GaAs devices, 39th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 22-24, ISSN: 0160-8371
Li X, Hylton NP, Giannini V, et al., 2012, 3D device simulation of plasmonic solar cells, Information Optoelectronics, Nanofabrication and Testing, IONT 2012
The device-oriented modelling of plasmonic solar cells in frequency and three-dimensional spatial domains is presented. It enables the simulation of both electromagnetic and carrier transport response accurately for a comprehensive solar cell design. © 2012 OSA.
Gong W, Faist MA, Ekins-Daukes NJ, et al., 2012, Influence of energetic disorder on electroluminescence emission in polymer:fullerene solar cells, PHYSICAL REVIEW B, Vol: 86, ISSN: 1098-0121
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- Citations: 71
Yoshida M, Ekins-Daukes NJ, Farrell DJ, et al., 2012, Photon ratchet intermediate band solar cells, Applied Physics Letters, Vol: 100, ISSN: 1077-3118
In this paper, we propose an innovative concept for solar power conversion—the “photon ratchet” intermediate band solar cell (IBSC)—which may increase the photovoltaicenergy 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.
Chan N, Young T, Brindley H, et al., 2012, Validation of energy prediction method for a concentrator photovoltaic module in Toyohashi Japan, Progress in Photovoltaics, Pages: n/a-n/a
III–V concentrator photovoltaic systems attain high efficiency through the use of series connected multi-junction solar cells. As these solar cells absorb over distinct bands over the solar spectrum, they have a more complex response to real illumination conditions than conventional silicon solar cells. Estimates for annual energy yield made assuming fixed reference spectra can vary by up to 15% depending on the assumptions made. Using a detailed computer simulation, the behaviour of a 20-cell InGaP/In0.01GaAs/Ge multi-junction concentrator system was simulated in 5-min intervals over an entire year, accounting for changes in direct normal irradiance, humidity, temperature and aerosol optical depth. The simulation was compared with concentrator system monitoring data taken over the same period and excellent agreement (within 2%) in the annual energy yield was obtained. Air mass, aerosol optical depth and precipitable water have been identified as atmospheric parameters with the largest impact on system efficiency.
Cheng YY, Fueckel B, MacQueen RW, et al., 2012, Improving the light-harvesting of amorphous silicon solar cells with photochemical upconversion, ENERGY & ENVIRONMENTAL SCIENCE, Vol: 5, Pages: 6953-6959, ISSN: 1754-5692
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- Citations: 322
Chan NLA, Ekins-Daukes NJ, Adams JGJ, et al., 2012, Optimal Bandgap Combinations-Does Material Quality Matter?, IEEE JOURNAL OF PHOTOVOLTAICS, Vol: 2, Pages: 202-208, ISSN: 2156-3381
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- Citations: 27
Faist MA, Kirchartz T, Gong W, et al., 2012, Competition between the Charge Transfer State and the Singlet States of Donor or Acceptor Limiting the Efficiency in Polymer:Fullerene Solar Cells, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Vol: 134, Pages: 685-692, ISSN: 0002-7863
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- Citations: 225
Clady R, Tayebjee MJY, Aliberti P, et al., 2012, Interplay between the hot phonon effect and intervalley scattering on the cooling rate of hot carriers in GaAs and InP, PROGRESS IN PHOTOVOLTAICS, Vol: 20, Pages: 82-92, ISSN: 1062-7995
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- Citations: 62
Lee K-H, Barnham KWJ, Connolly JP, et al., 2012, Demonstration of Photon Coupling in Dual Multiple-Quantum-Well Solar Cells, IEEE JOURNAL OF PHOTOVOLTAICS, Vol: 2, Pages: 68-74, ISSN: 2156-3381
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- Citations: 36
Bremner S, Ghosh K, Ekins-Daukes N, et al., 2012, ISSUES IN THE PHYSICAL MEASUREMENT OF THE INTERMEDIATE BAND EFFECT, 38th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE
Lumb MP, Gonzalez M, Vurgaftman I, et al., 2012, Simulation of novel InAlAsSb solar cells, Conference on Physics, Simulation and Photonic Engineering of Photovoltaic Devices, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 33
Li X, 2012, Aluminum Nanoparticles for Efficient Light-trapping in Plasmonic Gallium Arsenide Solar Cells, 2012 ASIA COMMUNICATIONS AND PHOTONICS CONFERENCE (ACP), ISSN: 2162-108X
Chan NLA, Brindley HE, Ekins-Daukes NJ, 2012, Quantifying the Impact of Individual Atmospheric Parameters on CPV System Power and Energy Yield, 38th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 922-927
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- Citations: 5
Cheng YY, Fueckel B, Schulze T, et al., 2012, Improving the light-harvesting of second generation solar cells with photochemical upconversion, Conference on Organic Photovoltaics XIII Part of the Symposium on Organic Photonics Plus Electronics at the SPIE Optics Plus Photonics International Meeting, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
Hirst LC, Fuehrer M, Farrell DJ, et al., 2012, InGaAs/GaAsP quantum wells for hot carrier solar cells, Conference on Physics, Simulation and Photonic Engineering of Photovoltaic Devices, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 17
Schulze TF, Cheng YY, Fueckel B, et al., 2012, Photochemical Upconversion Enhanced Solar Cells: Effect of a Back Reflector, AUSTRALIAN JOURNAL OF CHEMISTRY, Vol: 65, Pages: 480-485, ISSN: 0004-9425
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- Citations: 75
Braun A, Vossier A, Katz EA, et al., 2012, Multiple-bandgap vertical-junction architectures for ultra-efficient concentrator solar cells, Energy & Environmental Science, Vol: 5, Pages: 8523-8527
Führer MF, Adams JGJ, Barnham KWJ, et al., 2011, Extensible modelling framework for nanostructured III-V solar cells, Pages: 002615-002618, ISSN: 0160-8371
The use of nanostructures has been shown to provide practical performance enhancements to high-efficiency III-V based solar cells by permitting sub-bandgap tuneable absorption. Nanostructures present a fertile ground for new solar cell technologies, and an improved understanding of fundamental processes may even lead to functional intermediate band and hot-carrier devices. As the fundamental processes occurring in nanostructured solar cells are complex and not easily observable, the study of such devices often requires the analysis of data derived from experimental characterisation techniques using computer models. Models exist for many individual aspects of these nanostructured solar cells, but as yet no comprehensive modelling solution exists. We report on our progress to produce an extendable abstract modelling framework written in the high-level programming language Python. The framework is intended for deployment both as back-end to a variety of interfaces for specialised modelling purposes, and as a library of methods and classes for use at source-code level, allowing adaptation to a wide variety of research problems. Significant code abstraction, such as sequestering complex materials parameterisation behind a simple material object allows simple scripts to do complex work. Modules underway cover several device simulation tiers, including fundamental processes such as quantum well and dot absorption and recombination, as well as device level simulations such as spatial bias mapping using equivalent circuits and multijunction IV characteristics. These simulations correlate with and derive experimental data from characterisation techniques including spatially and temporally resolved electro- and photoluminescence spectroscopy, fourier-transform infrared spectroscopy, and others. © 2011 IEEE.
Hirst L, Führer M, Farrell DJ, et al., 2011, Hot carrier dynamics in InGaAs/GaAsP quantum well solar cells, Pages: 003302-003306, ISSN: 0160-8371
A hot carrier solar cell is a device with a steady-state carrier population which is described by a higher temperature than the surrounding lattice. Thermalisation loss is reduced in such a device, offering the potential for substantial efficiency advantages over single junction solar cells. Despite clear efficiency benefits no real world device has ever been developed, partly because of the difficulty of developing a suitable absorber material with sufficiently limited interaction between excited carriers and lattice phonons. This study evaluates the suitability of strain balanced InGaAs/GaAsP quantum well structures as hot carrier absorbers. Ultrafast time resolved photoluminescence (TRPL) spectroscopy measurements are presented which demonstrate hot carrier populations beyond 2ns after excitation in a deep well sample. Continuous wave photoluminescence (CWPL) spectroscopy was used to compare steady-state carrier populations in deep and shallow well samples. In both cases hot distributions were observed under photon flux density greater than 10,000 Suns equivalent. Increasing incident photon flux density was shown to increase carrier distribution temperature, suggesting that the hot carrier effect might be enhanced in a multiple QW structure with better well region absorption. It was also found that the deep well sample achieved significantly higher carrier distribution temperatures than the shallow well sample, demonstrating that increasing quantum confinement further inhibits thermalisation pathways. This study provides a guide to the development of hot carrier solar cells as it indicates deep multiple quantum well samples might exhibit an enhanced hot carrier effect. Strain Balanced InGaAs/GaAsP is a particularly suitable material system for growing this type of structure, making it an exciting prospect for the development of a hot carrier absorber. © 2011 IEEE.
Piper R, Yoshida M, Ekins-Daukes N, et al., 2011, Two-photon triplet-triplet annihilation upconversion for photovoltaics, Pages: 003632-003635, ISSN: 0160-8371
Upconversion is a promising technique for significantly enhancing the efficiency of photovoltaic cells. Molecular systems provide an environment in which long lived triplet states can be exploited to achieve high upconversion efficiencies under solar illumination. We report on the investigation of bi-molecular triplet-triplet annihilation upconversion (TTA-UC) in a Palladium (II) tetrakisquinoxalino porphyrin (PQ 4Pd)/rubrene solution. These molecules were studied in solution using UV/VIS spectroscopy to determine their stability in air over a period of weeks. Transient absorption spectroscopy (TAS) was used to directly measure the lifetime of triplet states within these mixtures and hence determine the photoinduced kinetics of the system. The lifetime of porphyrin triplets was reduced from 92.4 μs in pristine PQ 4Pd to 2.4 μs in the presence of rubrene. From this change, the rate constant associated with triplet energy transfer (k TET) was calculated as 3.38 × 10 8M -1s -1. Additionally, a reduction in the absorption of 530 nm light (the ground state rubrene absorption peak) was observed, while the mixture was pumped at the absorption peak of the porphyrin (670 nm). This change became apparent nearly 6 μs after the laser pulse, showing energy transfer from the porphyrin to the rubrene, and allowing further insight into the kinetics of the mechanism. © 2011 IEEE.
Walters RJ, González M, Tischler JG, et al., 2011, Design of an achievable, all lattice-matched multijunction solar cell using InGaAlAsSb, Pages: 000122-000126, ISSN: 0160-8371
A design for a realistically achievable, multijunction solar cell based on all lattice-matched materials with >50% projected efficiencies under concentration is presented. Using quaternary materials such as InAlAsSb and InGaAlAs at stochiometries lattice-matched to InP substrates, direct bandgaps ranging from 0.74eV up to ∼1.8eV, ideal for solar energy conversion, can be achieved. In addition, multi-quantum well structures are used to reduce the band-gap further to <0.7 eV. A triple-junction (3J) solar cell using these materials is described, and in-depth modeling results are presented showing realistically achievable efficiencies of AM1.5D 500X of η ∼ 53% and AM0 1 Sun of η∼ 37%. © 2011 IEEE.
Hylton NP, Giannini V, Vercruysse D, et al., 2011, III-V plasmonic solar cells: Targeting absorption enhancements close to the GaAs band edge
Giannini V, Hylton NP, Li X, et al., 2011, Solar cells with a multi-functional plasmonic light concentration layer, Conference Record of the IEEE Photovoltaic Specialists Conference, Pages: 000864-000865, ISSN: 0160-8371
Conversion of solar energy into electricity is considered one of the most promising solutions to the energy problem. Conventional III-V solar cells are designed such that their optical depth for absorption relates directly to the thickness of the absorbing material. This results in relatively thick solar cell structures consuming valuable semiconductor material and increasing the solar cell manufacturing time[1]. The ability to manipulate light using plasmonics could be extremely advantageous, enabling the optical depth for absorption becomes much greater than the thickness of the absorber, resulting in enhanced light absorption in thin-film solar cells[1, 2]. © 2011 IEEE.
Hylton NP, Giannini V, Vercruysse D, et al., 2011, Plasmonic nanostructures for absorption enhancements close to the GaAs band edge, Conference Record of the IEEE Photovoltaic Specialists Conference, Pages: 003627-003630, ISSN: 0160-8371
In this paper we present the optical characterisation of periodic arrays of Au nanoparticles fabricated on both GaAs substrates and a triple junction solar cell structure. The nanoparticle arrays were designed to employ the localised surface plasmon resonances of the nanoparticles and diffraction effects arising from the periodicity of the arrays, at wavelengths close to the GaAs band edge. In principle effects such as these may be used to improve the absorption of light in solar cell structures and hence increase their efficiency. In particular, we aim to build upon the success of high efficiency GaAs based photovoltaic cells by targeting the spectral region close to the band edge, where the absorption strength in conventional GaAs solar cells is poor. We demonstrate from numerical simulations and experimental observation that by careful adjustment of the nanoparticle dimensions we can tune the localised surface plasmon resonance to the desired wavelength. Furthermore, we show evidence of the diffraction of incident light into lateral modes within the absorbing material, increasing the optical path length. This effect is associated with the periodic nature of the arrays, and can therefore also be spectrally tuned by controlling the spacing between the nanoparticles. Such periodic nanoparticle arrays therefore provide two methods of absorption enhancement that may be employed in the same structure. © 2011 IEEE.
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