Sn Perovskite Solar Cells with Tin Oxide Nanoparticle Layer as Hole Transport Layer
Takeshi Kitamura, Liang Wang, Zheng Zhang, Ajay Kumar Baranwal, Gaurav Kapil, Shahrir Razey Sahamir, Yoshitaka Sanehira, Hua̅n Bì, Tingli Ma, Qing Shen, Shuzi Hayase
Abstract
Tin perovskite solar cells (Sn–PVK-PVs) are a promising alternative to lead perovskite solar cells (Pb–PVK-PVs). Poly (3,4-ethylenedioxythiophene) polystyrene sulphonic acid (PEDOT:PSS) is employed as the hole transport layer (HTL). However, the matter of concern is the damage of the Sn-PVK layer by the acidic properties of the PEDOT:PSS. Therefore, PEDOT:PSS-free Sn–PVK-PV is eagerly awaited. In this paper, the inorganic hole collectors using commercially available SnO 2 nanoparticles (Nano SnO 2 ) are reported. It is well-known that Nano SnO 2 works as an electron transport layer for Pb–PVK-PVs. However, we found that the Nano SnO 2 surface was reduced to SnO x ( x < 2) nanoparticles (abbreviated as P-Nano SnO x ) when the Nano SnO 2 contacted with the Sn-PVK layer, and the resulting P-Nano SnO x works effectively as the HTL of the Sn–PVK-PVs. The efficiency of 9.77% is reported. Furthermore, P-Nano SnO x devices showed higher stability in comparison to PEDOT:PSS devices.