Performance Dependence of Organic Solar Cells as a Function of Active Layer Thickness, Luminous Intensity and Temperature of Thermal Annealing

Abstract

Photovoltaic cells are optoelectronic devices for converting light energy into electrical energy. This work studies the effect of the active layer thickness on the performances of the inverted organic solar cells. The structures of the devices manufactured are Glass/ITO/ZnO NPS/P3HT:PCBM/PEDOT(FO10)/Ag. The active layer based on a blend of poly (3-hexylthiophene) and fullerene with a ratio of 1:0.8 is spin-coating at different speeds in order to obtain different thicknesses. ZnO NPS (30 nm) were used to improve electron transport between ITO and the active layer. PEDOT (F010) (40 nm) were used as a hole transport layer. The commercial ITO used in this study has a sheet resistance of 7 Ω/□ for a thickness of 110 nm. The fabrication and the characterization of the cells as well as the optical properties of materials used and the photovoltaic parameters of the solar cells are reported in the paper. A direct relation between the active layer thickness and efficiency of the inverted organic solar cells is proved. An efficiency of 4.36 % is obtained for 200 nm of P3HT:PCBM. The effect of light intensity and the thermal annealing on the performances of photovoltaic cells are discussed. The characterizations of the cells show that the luminous intensity influences the electrical and optical parameters of organic solar cells.