The future of perovskite solar cells (PSCs) is increasingly aligned with real‐world applications, especially in semi‐transparent building‐integrated photovoltaics, tandem configurations, and flexible optoelectronics, where achieving an optimal balance of efficiency, stability, and scalability is critical. This article proposes a dual‐optimization strategy that concurrently engineers both the perovskite absorber and hole transport layer (HTL), a rarely explored yet crucial approach. Partial substitution of Pb 2+ with Ba 2+ in the bromine‐rich, wide‐bandgap CsPbIBr 2 absorber ( E g ≈ 2.12 eV) improves crystallinity, grain morphology, and defect passivation, enhancing photostability and enabling spectral tunability for tandem and UV‐selective applications. Using numerical simulations, three benchmark HTLs, spiro‐OMeTAD, PEDOT:PSS, and P3HT, are evaluated, highlighting how optimal energy alignment and refined hetero‐interface engineering enhance charge extraction while reducing interfacial recombination in Ba 2+ ‐doped CsPbIBr 2 ‐based PSCs. The optimized device (FTO/SnO 2 /CsPb(Ba)IBr 2 /HTL/Au) achieves a power conversion efficiency of 15.63% by suppressing interface trap density to 1 × 10 9 cm −2 at the absorber/HTL junction. The article also explores the impact of absorber and HTL thicknesses, interfacial defect densities, carrier capture cross‐sections, density of states, and parasitic resistances on optoelectronic behavior. These results underscore the importance of synergistic absorber‐HTL coengineering and parameter tuning for high‐efficiency, stable, application‐ready all‐inorganic PSCs.
Rasheed et al. (Sun,) studied this question.