Optimized Mixed Halide Triple Cation Perovskite Based Indoor Photovoltaic Device Architecture with Ultrahigh Open Circuit Voltage and Efficiency > 42%

Indoor photovoltaics have attracted greater interest in applications of Internet of Things (IoT) devices. Herein, using the SCAPS 1D software, the output characteristics of photovoltaic devices utilizing Cs 0.08 (MA 0.17 FA 0.83 ) 0.92 Pb(I 0.83 Br 0.17 ) 3 are comprehensively investigated, denoted as PVK, with a bandgap of 1.76 eV, as an active layer under light‐emitting diode (LED) excitation of 3 W m −2 . For the optimization, various materials such as C 60 , PCBM, SnO 2 , TiO 2 , and WS 2 as electron transport layer (ETL) and Cu 2 O, PEDOT: PSS, Spiro‐OMETAD, NiO, and CuI as hole transport layer (HTL) are used. Parameters including the thickness and doping density of all layers, absorber defect density, the interface defect density of ETL/PVK and HTL/PVK, and the device's series and shunt resistance are optimized. The optimized device of FTO/SnO 2 /PVK/Cu 2 O/Au exhibits the highest PCE of 42.62%, with V OC of 1.27 V. Further, the simulations demonstrate that as the incident power ( P in ) increases from 0.3 to 10 W m −2 , the V OC increases from 1.13 to 1.31 V, highlighting the importance of stable V OC over photocurrent for practical IoT applications. This study contributes to the experimental development of high‐efficiency PVK indoor photovoltaics.