Analysis of opto-electrical, trap complexity and defect density in Cu–Zn–Ge–S/Se kesterite thin-film solar cell

Kesterite photovoltaic have received a lot of attention for its cheap cost and high efficiency. But, their performance efficiency is less than 12%. Its performances are restricted by the formation of defects that reduce short-circuit current by creating deep traps which undergo recombination. An approach, replacing Sn with Ge as Cu–Zn–Ge–S/Se (CZGS)/(CZGSe) kesterite solar cell is investigated to reduce defect development. In this article, various loss mechanisms that impact on the performance of CZGS/Se solar cells are investigated and compared. The impact of electrical, optical and various loss strategies such as radiative and non radiative recombination is investigated in depth. Additionally, trap and defect state densities are also propagated to the absorber layer. In the presence of defect states, the efficiency of the kesterite solar cell is significantly damaged and degraded about 11%.