Imperial College London

Dr N.J. (Ned) Ekins-Daukes

Faculty of Natural SciencesDepartment of Physics

Academic Visitor
 
 
 
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Contact

 

+44 (0)20 7594 6675n.ekins-daukes Website

 
 
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Location

 

H1002Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
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284 results found

Pusch A, Römer U, Culcer D, Ekins-Daukes NJet al., 2023, Energy Conversion Efficiency of the Bulk Photovoltaic Effect, PRX Energy, Vol: 2

Journal article

Li J, Huang J, Ma F, Sun H, Cong J, Privat K, Webster RF, Cheong S, Yao Y, Chin RL, Yuan X, He M, Sun K, Li H, Mai Y, Hameiri Z, Ekins-Daukes NJ, Tilley RD, Unold T, Green MA, Hao Xet al., 2022, Unveiling microscopic carrier loss mechanisms in 12% efficient Cu<inf>2</inf>ZnSnSe<inf>4</inf> solar cells, Nature Energy, Vol: 7, Pages: 754-764

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 Cu2ZnSnSe4 (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 (~104 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.

Journal article

Tabernig SW, Soeriyadi AH, Romer U, Pusch A, Lamers D, Juhl MK, Payne DNR, Nielsen MP, Polman A, Ekins-Daukes NJet al., 2022, Avoiding Shading Losses in Concentrator Photovoltaics Using a Soft-Imprinted Cloaking Geometry, IEEE JOURNAL OF PHOTOVOLTAICS, Vol: 12, Pages: 1116-1127, ISSN: 2156-3381

Journal article

Nielsen MP, Pusch A, Sazzad MH, Pearce PM, Reece PJ, Ekins-Daukes NJet al., 2022, Thermoradiative Power Conversion from HgCdTe Photodiodes and Their Current-Voltage Characteristics, ACS PHOTONICS, Vol: 9, Pages: 1535-1540, ISSN: 2330-4022

Journal article

Liu M, Romer U, Ekins-Daukes NJ, Lennon Aet al., 2022, Optical analysis of light management for finger designs in CPV systems, PROGRESS IN PHOTOVOLTAICS, Vol: 30, Pages: 1219-1227, ISSN: 1062-7995

Journal article

Gholizadeh EM, Prasad SKK, Gillan L, Nielsen MP, Ekins-Daukes NJ, McCamey DR, Tayebjee MJY, Schmidt TWet al., 2021, Singlet and Triplet Exciton Dynamics of Violanthrone, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 125, Pages: 22464-22471, ISSN: 1932-7447

Journal article

Yamaguchi M, Dimroth F, Geisz JF, Ekins-Daukes NJet al., 2021, Multi-junction solar cells paving the way for super high-efficiency, JOURNAL OF APPLIED PHYSICS, Vol: 129, ISSN: 0021-8979

Journal article

Jiang Y, Nielsen MP, Baldacchino AJ, Green MA, McCamey DR, Tayebjee MJY, Schmidt TW, Ekins-Daukes NJet al., 2021, Singlet fission and tandem solar cells reduce thermal degradation and enhance lifespan, PROGRESS IN PHOTOVOLTAICS, Vol: 29, Pages: 899-906, ISSN: 1062-7995

Journal article

Pusch A, Bremner SP, Tayebjee MJY, Daukes NJEet al., 2021, Microscopic reversibility demands lower open circuit voltage in multiple exciton generation solar cells, APPLIED PHYSICS LETTERS, Vol: 118, ISSN: 0003-6951

Journal article

Sogabe T, Hung C-Y, Tamaki R, Tomic S, Yamaguchi K, Ekins-Daukes N, Okada Yet al., 2021, Experimental demonstration of energy-transfer ratchet intermediate-band solar cell, COMMUNICATIONS PHYSICS, Vol: 4, ISSN: 2399-3650

Journal article

Steiner MA, France RM, Buencuerpo J, Geisz JF, Nielsen MP, Pusch A, Olavarria WJ, Young M, Ekins-Daukes NJet al., 2021, 32.9% efficient tandem solar cell with strain-balanced GaInAs/GaAsP quantum wells, 48th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 1084-1085, ISSN: 0160-8371

Conference paper

Zhou Z, Jiang Y, Ekins-Daukes N, Keevers M, Green MAet al., 2021, Optical and Thermal Emission Benefits of Differently Textured Glass for Photovoltaic Modules, IEEE JOURNAL OF PHOTOVOLTAICS, Vol: 11, Pages: 131-137, ISSN: 2156-3381

Journal article

Liu M, Romer U, Ekins-Daukes NJ, Lennon Aet al., 2021, Optical Analysis of Secondary Optics for Solar Concentrators with a View to Optimising Cell Metallisation, 48th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 2270-2272, ISSN: 0160-8371

Conference paper

Steiner MA, France RM, Buencuerpo J, Geisz JF, Nielsen MP, Pusch A, Olavarria WJ, Young M, Ekins-Daukes NJet al., 2020, High Efficiency Inverted GaAs and GaInP/GaAs Solar Cells With Strain-Balanced GaInAs/GaAsP Quantum Wells, ADVANCED ENERGY MATERIALS, Vol: 11, ISSN: 1614-6832

Journal article

Liu M, Soeriyadi AH, Song N, Hsiao PC, Romer U, Ekins-Daukes N, Lennon Aet al., 2020, Formation Mechanism of Cu-based Ohmic Contacts for GaAs Solar Cells, Pages: 0829-0832, ISSN: 0160-8371

Copper contacts on GaAs are gaining increasing attention for low-cost high-efficiency solar cell devices. Cu/Ge/Pd and Cu/Pt/Ti/Pt contacts have been reported to achieve low specific contact resistivities in the range of 10_{-5}\ \mathrm{\Omega} \text{cm}_{2}. A preliminary study for the formation mechanism of these two Cu-based structures on both n-type and p-type GaAs substrates subjected to different thermal annealing conditions is reported. The results indicate that the formation of the Cu3Ge and PdGaxAsy compounds in conjunction with the creation of Ga vacancies are among the reasons for low contact resistance for n-GaAs. The high work function of Pt and high melting temperature of both Pt and Ti help to reduce the contact resistance for p-GaAs.

Conference paper

Rodriguez AS, de Santana T, MacGill I, Ekins-Daukes NJ, Reinders Aet al., 2020, A feasibility study of solar PV-powered electric cars using an interdisciplinary modeling approach for the electricity balance, CO2 emissions, and economic aspects: The cases of The Netherlands, Norway, Brazil, and Australia, PROGRESS IN PHOTOVOLTAICS, Vol: 28, Pages: 517-532, ISSN: 1062-7995

Journal article

Aghaei M, Nitti M, Ekins-Daukes NJ, Reinders AHMEet al., 2020, Simulation of a Novel Configuration for Luminescent Solar Concentrator Photovoltaic Devices Using Bifacial Silicon Solar Cells, APPLIED SCIENCES-BASEL, Vol: 10

Journal article

Pearce P, Sayre L, Johnson A, Hirst L, Ekins-Daukes Net al., 2020, Design of photonic light-trapping structures for ultra-thin solar cells, Conference on Physics, Simulation, and Photonic Engineering of Photovoltaic Devices IX, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Liu M, Soeriyadi AH, Song N, Hsiao P-C, Romer U, Ekins-Daukes N, Lennon Aet al., 2020, Formation Mechanism of Cu-based Ohmic Contacts for GaAs Solar Cells, 47th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 829-832, ISSN: 0160-8371

Conference paper

Pusch A, Dubajic M, Ekins-Daukes NJ, Bremner Set al., 2020, Fundamental Aspects of Hot Carrier Solar Cell Operation, 47th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 2227-2232, ISSN: 0160-8371

Conference paper

Ekins-Daukes NJ, Sazzad MH, Al Kiyumi L, Nielsen MP, Reece P, Mellor A, Green MA, Pusch Aet al., 2020, Generating Power at Night Using a Thermoradiative Diode, How is this Possible?, 47th IEEE Photovoltaic Specialists Conference (PVSC), Publisher: IEEE, Pages: 2214-2218, ISSN: 0160-8371

Conference paper

Pusch A, Gordon JM, Mellor A, Krich JJ, Ekins-Daukes NJet al., 2019, Fundamental Efficiency Bounds for the Conversion of a Radiative Heat Engine's Own Emission into Work, PHYSICAL REVIEW APPLIED, Vol: 12, ISSN: 2331-7019

Journal article

Gentillon P, Singh S, Lakshman S, Zhang Z, Paduthol A, Ekins-Daukes NJ, Chan QN, Taylor RAet al., 2019, A comprehensive experimental characterisation of a novel porous media combustion-based thermophotovoltaic system with controlled emission, APPLIED ENERGY, Vol: 254, ISSN: 0306-2619

Journal article

Pusch A, Ekins-Daukes NJ, 2019, Voltage Matching, Etendue, and Ratchet Steps in Advanced-Concept Solar Cells, PHYSICAL REVIEW APPLIED, Vol: 12, ISSN: 2331-7019

Journal article

Steiner MA, Barraugh CD, Aldridge CW, Alvarez IB, Friedman DJ, Ekins-Daukes NJ, Deutsch TG, Young JLet al., 2019, Photoelectrochemical water splitting using strain-balanced multiple quantum well photovoltaic cells, SUSTAINABLE ENERGY & FUELS, Vol: 3, Pages: 2837-2844, ISSN: 2398-4902

Journal article

Alonso Alvarez D, Weiss C, Fernandez J, Janz S, Ekins-Daukes Net al., 2019, Assessing the operating temperature of multi-junction solar cells with novel rear side layer stack and local electrical contacts, Solar Energy Materials and Solar Cells, Vol: 200, ISSN: 0927-0248

Sub-bandgap sunlight provides a source of heat generation in solar cells that is detrimental to performance, especially in space applications where heat dissipation is limited. In this work we assess the impact that an advanced rear-side contact scheme for multi-junction solar cells has on the cell temperature. Our results show that this scheme reduces the optical power absorption below the bandgap of germanium by 81% compared to a standard, full metallization design. Measurements of the electrical and thermal power fluxes performed in vacuum demonstrate that this lower near-infrared light absorption results in 8% less heat dissipated in the cell with the novel rear-side contact scheme when operating at 25 ºC. Modelling of the operating temperature for both cells when fully encapsulated with glass indicates that this effect will also result in a reduction of the operating temperature of 9 ºC for the novel design.

Journal article

Cui X, Sun K, Huang J, Yun JS, Lee C-Y, Yan C, Sun H, Zhang Y, Xue C, Eder K, Yang L, Cairney JM, Seidel J, Ekins-Daukes NJ, Green M, Hoex B, Hao Xet al., 2019, Cd-Free Cu2ZnSnS4 solar cell with an efficiency greater than 10% enabled by Al2O3 passivation layers, ENERGY & ENVIRONMENTAL SCIENCE, Vol: 12, Pages: 2751-2764, ISSN: 1754-5692

Journal article

Ekins-Daukes N, Kay M, 2019, Brighten the dark skies, NATURE ENERGY, Vol: 4, Pages: 633-634, ISSN: 2058-7546

Journal article

Alonso Alvarez D, Augusto A, Pearce P, Ferre Llin L, Mellor A, Bowden S, Paul D, Ekins-Daukes Net al., 2019, Thermal emissivity of silicon heterojunction solar cells, Solar Energy Materials and Solar Cells, Vol: 201, Pages: 1-7, ISSN: 0927-0248

The aim of this work is to evaluate whether silicon heterojunction solar cells, lacking highly emissive, heavily doped silicon layers, could be better candidates for hybrid photovoltaic thermal collectors than standard aluminium-diffused back contact solar cells. To this end, the near and mid infrared emissivity of full silicon heterojunction solar cells, as well as of its constituent materials – crystalline silicon wafer, indium tin oxide, n-, i- and p-type amorphous silicon – have been assessed by means of ellipsometry and FTIR. The experimental results show that the thermal emissivity of these cells is actually as high as in the more traditional structures, ~80% at 8 μm. Detailed optical modelling combining raytracing and transfer matrix formalism shows that the emissivity in these cells originates in the transparent conductive oxide layers themselves, where the doping is not high enough to result in a reflection that exceeds the increased free carrier absorption. Further modelling suggests that it is possible to obtain lower emissivity solar cells, but that a careful optimization of the transparent conductive layer needs to be done to avoid hindering the photovoltaic performance.

Journal article

Dimmock JAR, Kauer M, Wu J, Liu H, Stavrinou PN, Ekins-Daukes NJet al., 2019, A metallic hot-carrier photovoltaic device, SEMICONDUCTOR SCIENCE AND TECHNOLOGY, Vol: 34, ISSN: 0268-1242

Journal article

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