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The role of nanoparticle inks in determining the performance of solution processed Cu 2 ZnSn(S,Se) 4 thin film solar cells
Author(s) -
Qu Yongtao,
Zoppi Guillaume,
Beattie Neil S.
Publication year - 2016
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.2756
Subject(s) - czts , materials science , nanoparticle , wurtzite crystal structure , solar cell , thin film , photovoltaics , fabrication , nanotechnology , chemical engineering , doping , open circuit voltage , optoelectronics , photovoltaic system , zinc , voltage , metallurgy , medicine , ecology , alternative medicine , physics , pathology , quantum mechanics , engineering , biology
Cu 2 ZnSnS 4 (CZTS) nanoparticle inks synthesized by the injection of metal precursors into a hot surfactant offer an attractive route to the fabrication of Earth‐abundant Cu 2 ZnSn(S,Se) 4 (CZTSSe) thin film photovoltaic absorber layers. In this work it is shown that the chemical reaction conditions used to produce CZTS nanoparticle inks have a fundamental influence on the performance of thin film solar cells made by converting the nanoparticles to large CZTSSe grains in a selenium rich atmosphere and subsequent cell completion. The reaction time, temperature and cooling rate of the nanoparticle fabrication process are found to affect doping level, secondary phases and crystal structure respectively. Specifically, prolonging the reaction offers a new route to increase the concentration of acceptor levels in CZTSSe photovoltaic absorbers and results in higher device efficiency through an increase in the open circuit voltage and a reduction in parasitic resistance. Quenching the reaction by rapid cooling introduces a wurtzite crystal structure in the nanoparticles which significantly degrades the device performance, while elevating the reaction temperature of the nanoparticle synthesis introduces a secondary phase Cu 2 SnS 3 in the nanoparticles and results in the highest cell efficiency of 6.26%. This is correlated with increased doping in the CZTSSe absorber and the results demonstrate a route to controlling this parameter. © 2016 The Authors. Progress in Photovoltaics: Research and Applications published by John Wiley & Sons, Ltd.