Ge²⁺掺杂全无机钙钛矿太阳能电池全光谱光吸收性能的优化

Abstract Full-spectrum light absorption is crucial for enhancing the power conversion efficiency (PCE) of perovskite solar cells (PSCs). This study explores the impact of Ge 2+ -doped on the ultraviolet–visible–near-infrared (UV–visible–NIR) light absorption of Cs-based all-inorganic perovskites using density functional theory and first-principles calculations. Four Ge 2+ -doped perovskites (CsSn 0.5 Ge 0.5 I 2.25 Cl 0.75 , CsSn 0.75 Ge 0.25 I 2 Cl, CsPb 0.25 Ge 0.75 I 2.75 Cl 0.25 , and CsSn 0.5 Ge 0.5 IBr 2 ) exhibit remarkable absorption from UV to NIR. Notably, CsSn 0.75 Ge 0.25 I 2 Cl demonstrates peak absorption coefficients of 1291315 cm −1 in the visible region and 1734261 cm −1 in the NIR region. Band structure and density of states analyses reveal that Ge 2+ incorporation narrows bandgaps, thereby enhancing light absorption. Deformation potential calculations indicate significantly improved carrier mobility , with CsSn 0.75 Ge 0.25 I 2 Cl exhibiting electron mobility of 6.68 cm 2 /Vs and hole mobility of 5.39 cm 2 /Vs. Device simulations of PSCs (Spiro-OMeTAD/Perovskite/TiO 2 /FTO) predict a PCE of nearly 29.23 % (V OC = 1.16 V, J SC = 21.33 mA/cm 2 , FF = 82.50 %) under optimized conditions (600 nm absorber thickness and 695.9 W/m 2 light intensity), representing a 32.5 % improvement in PCE compared to pre-optimization conditions. This study also examines defect density and temperature impacts on Ge 2+ -doped PSCs. As defect density rises from 10 15 to 10 19 cm −3 , performance metrics degrade significantly due to increased carrier recombination and energy loss. Increasing temperature from 300 to 400 K also reduces PCE for all materials. These findings underscore the importance of full-spectrum absorption engineering for enhancing all-inorganic lead-free PSC performance.