Surface Passivation With Phenethylammonium Iodide (Peai) To Enhance Efficiency In Perovskite Solar Cell

Abstract

Perovskite Solar Cells (Pscs) Have Attracted Significant Attention For Their Impressive Power Conversion Efficiencies (Pces) In Recent Years However, Further Improvements In Device Performance Remain A Major Challenge. One Of The Key Limiting Factors Is The Presence Of Surface Defects In The Perovskite Layer, Which Promote Nonradiative Recombination And Cause Carrier Transport Losses, Particularly At The InterfaceBetween The Perovskite And The Electron-Selective Contact Layer (E.G., C?????). To Address These Issues, Interface Engineering Of The Perovskite Absorber Layer Has Emerged As A Widely Adopted And Effective Strategy For Minimizing Interfacial Losses And Enhancing Overall Device Efficiency. Organic Ammonium Halide Salts Are Commonly Used As Surface Modifiers In The Form Of 2d Perovskites To Create 2d/3d Bilayer Structures That Enhance Efficiency And Stability. This Thesis Investigates The Use Of Phenethylammonium Iodide (Peai) As A 2d Passivation For Surface Passivation Of Triple-Cation Perovskite Materials, Specifically Cs0.05(Ma0.02fa0.98)0.95pb(I0.98br0.02)3.We Demonstrate That Peai Passivation Effectively Reduces Surface Defects, Suppresses Nonradiative Recombination, And Leads To Enhanced Charge Carrier Dynamics. As A Result, Devices Treated With Peai Achieve A Pce Of 20.6%, Compared To 18.9% For The Control Device. This Overall Improvement In Pce Primarily Arises From Increases InOpen-Circuit Voltage (Voc) And Fill Factor (Ff), Attributed To The Beneficial PassivationEffect Of The 2d Layer. This Is Further Supported By Enhanced Photoluminescence (Pl)And Electroluminescence (El) Emission. In Contrast, The Short-Circuit Current Density(Jsc) Remains Nearly Unchanged, Consistent With The Unaltered Optical Absorption AndExternal Quantum Efficiency (Eqe) Spectra. Despite Their Benefits, 2d PerovskiteLayers Can Damage The Underlying 3d Perovskite During Post-Annealing And Introduce Exciton Transport Barriers Due To Degradation Of The 2d Itself. To Avoid These Issues, We Directly Applied Phenethylammonium Iodide (Peai) Without Post-Annealing. This Prevents The Formation Of A Separate 2d Phase And Preserves Efficient Charge Transport In The 3d Structure, While Still Enhancing Device Performance.