Proceedings of International Conference on Perovskite and Organic Photovoltaics and Optoelectronics (IPEROP19)
Publication date: 23rd October 2018
Recently, inorganic CsPbX3 (X=I, Br) perovskite solar cells (PSCs) are attracting much attention due to their outstanding thermal stability and high-speed progress in performances. However, their energy losses (Eloss), defined as the energy loss between the bandgap of perovskite materials and the device open-circuit voltage (Voc) (Eloss= Eg-eVoc), are still very high compared with the organic-inorganic hybrid PSCs, which will deeply affect their performances. Thus reducing the Eloss will obviously improve the power conversion efficiency (PCE) of the devices. Here we provide a simple and efficient surface passivation method of SnO2 electron selective layer (ESL) using an ultra-thin SnO2 layer. After passivation, the Voc of the CsPbIBr2 solar cells was improved from 1.07 to 1.31 V, which is the highest Voc among ever-reported CsPbIBr2 solar cells. At the same time, the PCE of the carbon electrode based cells was enhanced from 4.71 to 7.00 %. Characterizations indicate that the faster carrier transformation through the interface and the larger charge recombination resistance are the main reasons for the high Voc and high performance of passivated SnO2 ESL based CsPbIBr2 PSCs.