A Review on Interface Engineering Strategies in Bromide‐Based Wide Bandgap Perovskite Solar Cells

In recent years, wide bandgap (WBG) perovskite solar cells (PSCs) have garnered significant attention due to their high open‐circuit voltage ( V OC ) and superior stability. This review comprehensively examines the bromide‐based (Br‐based) perovskites with bandgaps over 2.0 eV and their applications in photovoltaic devices, discussing research progress and interfacial engineering strategies across several types of WBG perovskites, including cesium lead bromide (CsPbBr 3 ), CsPbIBr 2 , methylamine lead bromide (MAPbBr 3 ), and formamidinium lead bromide (FAPbBr 3 ). The key challenges in developing Br‐based WBG PSCs include energy level misalignment, high defect density of perovskite films, and residual stress occurring in the fabrication process. Through interfacial passivation, charge transport layer (CTL) optimization, and antisolvent engineering, researchers can modulate perovskite crystallization, mitigate defects, minimize energy level misalignment, enhance carrier transport, release residual stress, and prevent ambient air infiltration, thereby improving the photovoltaic performance and stability of PSCs. Finally, this review prospects for the potential application directions and optimization strategies for Br‐based PSCs.