Carbon‐Based CsPbI 3 Perovskite Solar Cells: Progress, Challenges, and Opportunities

ABSTRACT All‐inorganic CsPbI 3 perovskite has been recognized as one of the most promising light‐absorbing materials owing to its favorable optical bandgap (≈1.7 eV) and excellent chemical stability. To date, CsPbI 3 perovskite solar cells (PSCs) based on conventional metal electrodes have realized power conversion efficiencies (PCEs) of over 22%, presenting a considerable commercial potential. However, such devices typically employ organic hole transport materials (HTMs) and metal electrodes, greatly lowering their operational stability. To address that, carbon materials have been introduced to form carbon‐based PSCs (C‐PSCs) by simultaneously replacing HTMs and metal electrode, effectively enhancing photovoltaic device stability. Since the initial report of CsPbI 3 C‐PSCs in 2016, the PCEs have reached over 20% at present. Nevertheless, it remains inferior to the Shockley‐Queisser (S‐Q) limit due to severe bulk defects and substantial interfacial energy level mismatch. Therefore, in this review, we comprehensively summarize and discuss the recent process of CsPbI 3 C‐PSCs over the past decade, including the device structure, work principle, preparation cost, intrinsic limitations, and performance enhancement strategies. And then, we provide a concise perspective on the current challenges and future opportunities regarding CsPbI 3 C‐PSCs.