Reducing Optical Reflection Loss for Perovskite Solar Cells Via Printable Mesoporous SiO2 Antireflection Coatings

Abstract The power conversion efficiency (PCE) of single‐junction perovskite solar cells (PSCs) is being rapidly promoted towards their theoretical limit, with a certified value of 25.7%. Reducing optical loss will further contribute to PCE improvement. Here, the optical loss including reflection loss, absorption loss, and transmission loss in printable mesoscopic perovskite solar cells (p‐MPSCs) is analyzed. A printable mesoporous SiO 2 antireflection coating for improving the transmittance of the fluorine‐doped tin oxide (FTO) glass substrate by reducing optical reflection at the air/glass interface is reported. With modulated porosity and thickness, the mesoporous SiO 2 film constructs a graded refractive index interface and increases the transmittance of FTO glass by ≈2%–4% in the spectral range of 350–800 nm at normal incident angle with the highest transmittance improved from 85% to 89%. The SiO 2 coating also exhibits wide‐angle and broadband antireflection properties. The coatings successfully help p‐MPSCs obtain about an average 3% enhancement in the short‐circuit current density ( J SC ) and PCE. This study demonstrates the necessity of optical management for efficient solar cells and provides a cost‐effective and scalable antireflection coating for the future realistic application of PSCs.