High-Performance Semi-Transparent Perovskite Solar Cells with over 22% Visible Transparency: Pushing the Limit through MXene Interface Engineering

Semi-transparent perovskite solar cells (ST-PSCs) haveattractedenormous attention recently due to their potential in building-integratedphotovoltaic. To obtain adequate average visible transmittance (AVT),a thin perovskite is commonly employed in ST-PSCs. While the thinnerperovskite layer has higher transparency, its light absorption efficiencyis reduced, and the device shows lower power conversion efficiency(PCE). In this work, a combination of high-quality transparent conductinglayers and surface engineering using 2D-MXene results in a superiorPCE. In situ high-temperature X-ray diffraction provides direct evidencethat the MXene interlayer retards the perovskite crystallization processand leads to larger perovskite grains with fewer grain boundaries,which are favorable for carrier transport. The interfacial carrierrecombination is decreased due to fewer defects in the perovskite.Consequently, the current density of the devices with MXene increasedsignificantly. Also, optimized indium tin oxide provides appreciabletransparency and conductivity as the top electrode. The semi-transparentdevice with a PCE of 14.78% and AVT of over 26.7% (400-800nm) was successfully obtained, outperforming most reported ST-PSCs.The unencapsulated device maintained 85.58% of its original efficiencyafter over 1000 h under ambient conditions. This work provides a newstrategy to prepare high-efficiency ST-PSCs with remarkable AVT andextended stability.

Automated summary

This research combines high-quality transparent conducting layers and surface engineering using 2D-MXene to improve the conversion efficiency of semi-transparent perovskite solar cells (ST-PSCs). The MXene interlayer retards the perovskite crystallization process, resulting in larger perovskite grains with fewer grain boundaries, which enhances carrier transport. The current density of the devices with MXene significantly increases due to decreased interfacial carrier recombination. The unencapsulated device maintains 85.58% of its original efficiency after over 1000 hours under ambient conditions.