The Effect of Energy Level of Transport Layer on the Performance of Ambient Air Prepared Perovskite Solar Cell: A SCAPS-1D Simulation Study

The perovskite solar cell (PSC) as an emerging and promising type has been extensively studied. In this study, a model for a PSC prepared in ambient air was established by using SCAPS-1D. After that, it was further analyzed through varying the defect density of the perovskite absorber layer (N-t), the thin film thickness and energy-level matching between the electron transport layer (ETL), the perovskite absorber layer and the hole transport layer (HTL), for a better understanding of the carrier features. The N-t varied from 1.000 x 10(11) to 1.000 x 10(17) cm(-3). The performance of the solar cell is promoted with improved N-t. When N-t is at 1.000 x 10(15) cm(-3), the carrier diffusion length reaches mu m, and the carrier lifetime comes to 200 nm. The thickness of the absorber layer was changed from 200 to 600 nm. It is shown that the absorber layer could be prepared thinner for reducing carrier recombination when at high N-t. The thickness effect of ETL and HTL is weakened, since N-t dominates the solar cell performance. The effect of the affinity of ETL (3.4-4.3 eV) and HTL (2.0-2.7 eV), together with three energy-level matching situations ETL(4.2)+HTL(2.5), ETL(4.0)+HTL(2.2) and ETL(4.0)+HTL(2.5) on the performance of the solar cell were analyzed. It was found that the HTL with valence band 0.05 eV lower than that of the perovskite absorber layer could have a blocking effect that reduced carrier recombination. The effect of energy-level matching becomes more important with improved N-t. Energy-level matching between the ETL and perovskite absorber layer turns out counterbalance characteristic on J(sc) and V-oc, and the ETL(4.0)+HTL(2.5) case can result in solar cell with J(sc) of 27.58 mA/cm(2), V-oc of 1.0713 V, FF of 66.02% and efficiency of 19.51%. The findings would be very useful for fabricating high-efficiency and low-cost PSC by a large-scale ambient air route.

Automated summary

This study established a model for perovskite solar cells prepared in ambient air and analyzed its characteristics. The findings suggest that the performance of the solar cell can be improved by optimizing defect density and energy-level matching.