Yohannes, Teketel (Professor)Tukue, Hagos2021-01-112023-11-092021-01-112023-11-092014-06-06http://etd.aau.edu.et/handle/12345678/24617The need for clean, inexpensive and renewable energy has increasingly turned research attention towards polymer photovoltaic cells. However, the performance efficiency of these devices is still low in comparison with silicon-based devics. The recent introduction of solvent additives has resulted in a remarkable increase in power-conversion efficiency by controlling the interpenetrating network morphology of the organic bulk heterojunction solar cells. In this study the effect of low boiling point solvent additives such as iodomethane, iodoethane and di-iodomethane on the photovoltaic porformance of TQ1:PC61BM (1:2) based organic BHJ solar cells with the device architecture glass/ITO/PEDOT-PSS/TQ1:PC61BM/Al were studied. It was shown that the highest PCE of 4.53% was obtained by solar cell made from a blend solution containing 3% (v/v) diiodomethane. Similarlly, devices made from blend solutions containing 3% (v/v) of iodomethane and iodoethane exhibited PCE of 3.28 and 3.76%, respectively. The addition of these solvent additives has mainly increased the short-circuit current density (Jsc) of the solar cells compared to pristine TQ1:PC61BM based solar cell. As confirmed from UV-Vis absorption and photoluminescence spectra, addition of these solvent additives has enhanced photon absorption and photoluminescence quenching efficiency, respectively. Hence, this study have shown that despite the high boiling point solvent additives, low boiling point solvent additives can improve the phase separation of the active layer that in turn enhances charge dissociation and PCE.enEnergy ConversionOrganic Solar CellsBulk HeterojunctionSolvent AdditivesTQ1Thesis