The Interplay between Dopant and the Surface Structure of an Electron Transport Layer in N719 Solid State Dye-Sensitized Solar Cells: An Analysis of Aluminum-doped Faceted TiO2 with Mg-CuCrO2 Transport Channels Using the SCAPS-1D Framework

Abstract

Solid state dye-sensitized solar cells (ssDSSCs) are attracting increasing attention due to their affordable manufacturing, adaptability to lightweight and flexible applications. This present work utilized solar capacitance simulation software to examine the performance of ssDSSCs with both Al³⁺ doped and undoped TiO₂ electron transport layer (ETL). The pure titanium dioxide based device gave an open circuit voltage V_oc, short circuit current density J_sc, fill factor FF and power conversion efficiency PCE 0.95 V, 15.16 mA cm⁻², 64.49% and 9.30%, respectively, while the aluminium doped TiO₂ presents 0.87 V, 18.53 mA cm⁻², 68.73% and 11.09% as V_oc, J_sc, FF and PCE, respectively. This shows that Al³⁺ doped ETL was more promising. The effects of using different hole transport layers (HTLs) were studied. Delafossite (Mg-CuCrO₂) was found to be the most potential HTL to dramatically improve device performance with V_oc 0.87 V, J_sc 19.16 mA cm⁻², FF 68.52% and PCE 11.44%. The performance of the fluorine-doped tin oxide (FTO)/Al-TiO₂/N719/Mg-CuCrO₂/C device was optimized by varying the ETL thickness and doping concentration, dye thickness and defect density, HTL thickness and doping concentration to obtain 0.16 μm, 10²⁰ cm⁻³, 0.9 μm, 10¹³ cm⁻², 0.6 and 10²² cm⁻³ as optimal values, respectively. This showed a noticeable performance with optimized PCE 23.75%, supported with FF 84.98%, J_sc 24.12 mA cm⁻² and V_oc 1.16 V. The effect of series and shunt resistances, temperature, metal work function, capacitance and Mott-Schottky plot were evaluated and found to affect the optimized device.