Enhancing Performance in P3HT:ICBA Organic Photovoltaics through IR Photon Harvesting with DIBSq Squaraine Dye

In this study, we analyze binary and ternary bulk heterojunction organic solar cells utilizing P3HT:ICBA and P3HT:ICBA:DIBSq blends. We investigate optical and electrical properties for different 2,4-bis[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl] squaraine (DIBSq) ratios, along with introducing a 140 °C annealing protocol. A comprehensive comparison of optical, electrical, and morphological aspects is conducted between annealed and non-annealed devices. UV-vis measurements unveil expanded near-infrared absorption due to DIBSq. Current–voltage characteristics and external quantum efficiency measurements reveal enhanced performance with increasing DIBSq ratios. Ternary devices achieve 3.96% efficiency with 10.079 mA cm² J_SC, 0.83 V V_OC, and 0.469 fill factor, compared to binary devices with 2.89% power conversion efficiency, 7.458 mA cm² J_SC, 0.795 V V_OC, and 0.488 fill factor. Efficiency diminishes beyond a specific DIBSq content. Atomic force microscopy explores morphological properties, showing slight root-mean-square roughness increase and small feature emergence with higher DIBSq concentrations, resulting in suboptimal 5% DIBSq device performance.