Effect of layer number on the properties of stable and flexible perovskite solar cells using two dimensional material

Abstract

Recently, the flexibility and stability of perovskite solar cells (PSCs) with high power-conversion efficiency (PCE) have attracted the interest of many research. Reliable flexible transparent conductive electrodes (TCEs) and high stability at the perovskite/transport layers interface are vital for increasing the performance of flexible- and stable-PSCs. Herein, we develop PSCs with two-dimensional graphene (Gr) TCEs and MoS2 electron transport layers (ETLs). By modulating the number of layers (L) of Gr (LGr) and MoS2 (LMoS2), the maximum PCE of PSCs were 14.42 and 12.92% was achieved for PSCs fabricated on glass and polyethylene terephthalate substrates, respectively, at LGr = 2 and LMoS2 = 1. PSCs showed excellent stability as it lost only 18% of the initial PCE after 500 h. This is attributed to the improved ETL/perovskite interface. Moreover, the flexible PSCs retained 84% and 63% of the original PCE value after 1000 inner- and outer-bending cycles at a radius of curvature of 2 mm; thus, it is suitable for flexible devices.