[15a-A34-1~8] 13.10 Compound solar cells

[15a-A34-3] Characterization of a 12.3% efficient Cu₂Zn(Sn_1-xGe_x)Se₄ thin-film solar cell

Shinho Kim¹, Kang Min Kim¹, 〇hitoshi Tampo¹, Hajime Shibata¹, Shigeru Niki¹ (1.AIST)

Keywords:solar cell, CZTGSe, kesterite

In this study, we demonstrate new efficiency of Cu₂Zn(Sn_1-xGe_x)Se₄ (CZTGSe) thin-film solar cell. We archived new conversion efficiency of 12.3% with a very high fill factor (FF = 0.727), which is the main parameter for high conversion efficiency (Fig. 1). In addition, greatly improved open circuit voltage (V_OC) deficit (E_g/q-V_OC = 0.583 V, q: electron charge) was observed. We fitted I-V curve using single diode model to compare with our previous results, and found high FF device showed reduced diode ideality factor (A) and reverse saturation current (J₀). Improved diode parameters, V_OC deficit, A and J₀, are indicating improved junction quality and reduced recombination at the absorber/buffer interface and/or space chare region, which can be possible reason for highly improved FF.