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_0.17FA_0.83)_0.92Pb(I_0.83Br_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 C₆₀, PCBM, SnO₂, TiO₂, and WS₂ as electron transport layer (ETL) and Cu₂O, 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/SnO₂/PVK/Cu₂O/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.