Atomic Layer Deposited ZnO–SnO₂ Electron Transport Bilayer for Wide‐Bandgap Perovskite Solar Cells

Abstract

High-quality electron transport layer (ETL) is a prerequisite for high-performance wide-bandgap mixed-halide perovskite solar cells (PSCs), which is critical for efficient perovskite/silicon tandem solar cells. Herein, an atomic layer deposited ZnO-SnO 2 bilayer ETL for wide-bandgap PSCs is reported, featuring a high uniformity and conformality over a large area. The ZnO-SnO 2 bilayer shows a matched band alignment with wide-bandgap perovskite for efficient electron extraction and transport, with a lower nonradiative recombination. As a result, a champion power conversion efficiency of 18.1% is achieved on the ZnO-SnO 2 bilayer-based wide-bandgap PSCs featuring an ultrahigh open-circuit voltage (V oc ) of 1.233 V, which is the highest value for wide-bandgap PSCs without any surface passivation. In addition, the atomic layer deposition ZnO-SnO 2 bilayer exhibits very good surface passivation and conformality on crystalline silicon surfaces, which makes it attractive to be applied for perovskite/silicon tandem solar cells with a higher V oc and textured surfaces.

Pure-Phase, Large-Grained Wide-Band-Gap Perovskite Films for High-Efficiency, Four-Terminal Perovskite/Silicon Tandem Solar Cells

“…The J sc integrated from the EQE spectra is determined to be 20.89 mA/cm 2 , which is in line with that measured from the J – V curve. The slight discrepancy may be ascribed to the spectra mismatch between the simulated AM 1.5G illumination and the xenon light source of the EQE test, which has been frequently observed in previous works. − …”

Magnetron Sputtering Zn2SnO4 Electron‐Transport Layer for All Room‐Temperature‐Processed Perovskite Solar Cells

“…The ZSO ETL presents a larger slope than these of ZnO and SnO 2 , indicating a higher conductivity of ZSO ETL. [ 30 ] Therefore, the better band diagram and higher conductivity of ZSO ETL facilitate charge extractions from the perovskite layer to FTO. In addition, the scanning electron microscope (SEM) images of perovskite films grown on ZnO, SnO 2 , and ZSO ETLs were measured and shown in Figure 2c–e, respectively.…”

Sequential Deposition of Diluted Aqueous SnO2 Dispersion for Perovskite Solar Cells

“…However, there are other approaches to improve SnO 2 films deposited from the dispersion including varying the pH level, [30] solvent engineering, [20] and introducing different bilayer combinations with SnO 2 . [18,[31][32][33][34] The main idea of these approaches is to improve the morphology of the ETLs and reduce the surface trap states. DOI: 10.1002/solr.202400415…”