Enhanced photoelectric properties in flexible CZTS solar cells using O/M/O structure

Poor flexibility of ITO films restricted the photovoltaic characteristics of flexible CZTS solar cells (SCs). In this study, ZnO/Ag/ZnO (ZAZ) transparent conductive films with high transmittance and flexibility were prepared and applied as the transparent conductive layer of flexible CZTS SCs to enhance the photovoltaic characteristics. By regulating the thickness of the Ag metal layer, ZnO/Ag9nm/ZnO (ZA9Z) provided the best photovoltaic properties: resistivity 9.16 × 10−5 Ω cm, average transmittance 95.8%, maximum transmittance of 97.4%, and figure of merit (FOM) 78.4 10−3 Ω−1. Moreover, CZTS SCs with ZA9Z film showed a power conversion efficiency (PCE) of 6.69%, almost 13% higher than those with ITO film. The PCE values of the SCs with ZA9Z film were 6.09 and 4.31 after a bending diameter of 8 mm and 1000 cyclic bending, respectively, while the ratio of PCE of the SCs with ZA9Z film to that of the SCs with ITO film was 6.88 and 12.31 under these conditions, respectively, showing that the CZTS SCs with ZA9Z film are of excellent flexibility. [Display omitted] •Photoelectric properties of CZTS SCs was enhanced by using ZAZ film instead of ITO.•The average transmittance of ZAZ films from 400 to 800 nm is up to 95.8%.•ZA9Z SCs present a PCE of 6.69% at unbending, which is almost 13% higher than ITOs.•The PCE of ZA9Z SCs is 6.08 at an 8 mm bending diameter, higher than ITO SCs of 0.88.•The PCE ratio of ZA9Z SCs to ITO SCs was 12.31 after 1000 cyclic bending.