Electronic devices comprising bonded organic compounds are getting advanced at a tremendous speed as a result of their distinguished electrical behaviour and photonics tendency along with simple processing conditions. In this regard, here we report on the fabrication of an efficient solution-processed small molecule solar cells based on the combination of DTS[PTTH2]2 as a donor and PC71BM as an acceptor. The active layer configurations were framed through solvent engineering concepts implementing a blend of different additive concentrations through the spray-coating technique. The optical absorption phenomenon was investigated through the UV–visible spectrum for the wavelength sweep ranging from 300 to 900 nm. Studies related to the surface pattern, phase separation and morphology were carried out through Scanning electron microscopy and Atomic force microscopy. JV values were analysed through solar simulator under illumination mode. IPCE analysis and ageing studies were performed for better device analysis. The efficiency of about 8.16% is achieved for the particular active layer configuration holding 0.3% DIO additive with improved stability and photovoltaic parameters. These results provoke the progression of organic solar cells and also explain that the cells fabricated through small molecule-based donors using the spray-coating method can contend readily with the polymeric counterparts. © 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.