Properties of Perovskite Solar Cells with Low Temperature Sintered SnO2 Electron Transport Layers

Abstract

This study investigated the photovoltaic properties and microstructure of perovskite solar cells (PSCs) with an ITO/SnO2/perovskite/HTL/Au electrode configuration, developed with varying sintering temperatures (100~200°C). The goal was to use SnO2 ink as the electron transport layer (ETL) by low-temperature sintering. TGA-DTA analysis was conducted to determine the optimum sintering temperature of the SnO2 ink and the photovoltaic properties were examined by solar simulator analysis. To analyze the microstructure, a 3D profiler, optical microscope, and scanning electron microscopy (SEM) were used. The TGA-DTA analysis results show that SnO2 ink was effectively sintered at the low temperature of 80°C and above. As for the photovoltaic(PV) properties, the PV efficiency was approximately 15% at 120~150°C, and increased to a maximum of 17.16% at 180°C, and then fell to 12% at 200°C. The RMS value, a representation of surface roughness, of the SnO2 layer according to sintering temperature incrementally decreased, reached its lowest at 180°C, before finally increasing. The microstructure analysis showed that the perovskite layer formed on the SnO2 at a sintering temperature of 180°C had a relatively greater grain size of 402 nm and a thickness of 432 nm, thereby improving the PSC’s PV properties. These results suggest it is possible to implement a PCS with SnO2 ETL by low temperature sintering process.