All‐SnO<sub>2</sub>‐Based Conformal Electron Transport Layer for Efficient Perovskite Solar Cells
Bin Huang, Likai Zheng, Ruixiong Hu, Yimin Xuan
Abstract
Abstract The fabrication of high‐performance perovskite solar cells on high‐haze fluorine‐doped tin oxide (FTO) substrates with superior light‐trapping capabilities necessitates a highly conformal electron transport layer at the bottom interface. Herein, a conformal low‐temperature processable all‐SnO 2 ‐based electron transport layer (ETL) is successfully developed on high‐haze FTO by well‐anchoring a polyacrylic acid‐stabilized quantum dot‐SnO 2 layer onto an atomic layer deposited SnO 2 layer with a dense hydroxyl surface. The obtained ETL demonstrates excellent capabilities in simultaneously homogenizing the surface contact potential distribution, blocking hole transport, and suppressing non‐radiative recombination. Consequently, a champion device is achieved that delivers a remarkable power conversion efficiency (PCE) of up to 24.97%, with V OC × FF reaching 87.09% of the Shockley‐Queisser limit at a bandgap of 1.54 eV, which is the highest value among the ALD SnO 2 ‐based PSCs. The homogeneous ETL further enabled the fabrication of a 1 cm 2 PSC with a PCE of 23.18% and only a 10 mV loss in V OC compared to smaller‐area PSCs, showcasing its potential for large‐scale commercial applications.