A Multi-Electron Transporting Layer for Efficient Perovskite Solar Cells

In this work, a multi-electron transporting layer (ETL) for efficient perovskite solar cells is investigated. The multi-ETL consists of five conditions including SnO2, SnO2/SnOx, TiO2, TiO2/SnO2, and TiO2/SnO2/SnOx. The best performance of PSC devices is found in the SnO2/SnOx double-layer and exhibits a power conversion efficiency equal to 18.39% higher than the device with a TiO2 single-layer of 14.57%. This enhancement in efficiency can be attributed to a decrease in charge transport resistance (R-ct) and an increase in charge recombination resistance (R-rec). In addition, R-ct and R-rec can be used to explain the comparable power conversion efficiency (PCE) between a PSC with a SnO2/SnOx double-layer and a PSC with a triple-layer, which is due to the compensation effect of R-ct and R-rec parameters. Therefore, R-ct and R-rec are good parameters to explain the efficiency enhancement in PSC. Thus, the R-ct and R-rec from the electrochemical impedance spectroscopy (EIS) technique is an easy and alternative way to obtain information to understand and characterize the multi-ETL on PSC.

Automated summary

The study found that the multi-electron transporting layer consisting of SnO2/SnOx double-layer shows good performance for perovskite solar cells, with enhanced efficiency attributed to decreased charge transport resistance and increased charge recombination resistance. The R-ct and R-rec parameters from electrochemical impedance spectroscopy (EIS) technique can explain the efficiency enhancement in PSC devices.