Fabrication of solution processable perovskite solar cells under high humid conditions via optimization of TiO2 compact layer

Organic inorganic-based perovskites solar cells (PSCs) are quite prominent as next generation solar cells as they exhibit excellent properties as well as high power conversion efficiency. In spite of the high cost, interfacial recombinations and instability in ambient environment limit their commercialization. Herein, TiO2-based compact layer (c-TiO2) with different thicknesses is employed (nm) to study the charge transportation at interface and recombination in PSCs fabricated under high humid conditions (R-H similar to 80%). The thickness of CL was varied from 7nm to 35nm and was optimized by changing the precursor concentration as well as spinning speed. The prepared c-TiO2 and the mesoporous layer of TiO2 (m-TiO2) were thoroughly characterized using Raman spectroscopy, UV-Vis, cyclic voltammetry and electrochemical techniques. Furthermore, CuSCN was used as hole transporting layer (HTL) in PSCs owing to ease of handling and nominal cost. The optimized PSC is found to show that the power conversion efficiency (PCE) improved by 50% on varying the thickness of CL and is stable even under high humid conditions. The elevated performance of PSCs is ascribed to the appropriate thickness of CL which resulted in improved charge transportation and reduced electron hole recombinations.