The need for clean, inexpensive and renewable energy has increasingly turned researchrnattention towards polymer photovoltaic cells. However, the performance efficiency ofrnthese devices is still low in comparison with silicon-based devics. The recent introductionrnof solvent additives has resulted in a remarkable increase in power-conversion efficiencyrnby controlling the interpenetrating network morphology of the organic bulkrnheterojunction solar cells. In this study the effect of low boiling point solvent additivesrnsuch as iodomethane, iodoethane and di-iodomethane on the photovoltaic porformancernof TQ1:PC61BM (1:2) based organic BHJ solar cells with the device architecturernglass/ITO/PEDOT-PSS/TQ1:PC61BM/Al were studied. It was shown that the highest PCErnof 4.53% was obtained by solar cell made from a blend solution containing 3% (v/v) diiodomethane.rnSimilarlly, devices made from blend solutions containing 3% (v/v) ofrniodomethane and iodoethane exhibited PCE of 3.28 and 3.76%, respectively. Thernaddition of these solvent additives has mainly increased the short-circuit current densityrn(Jsc) of the solar cells compared to pristine TQ1:PC61BM based solar cell. As confirmedrnfrom UV-Vis absorption and photoluminescence spectra, addition of these solventrnadditives has enhanced photon absorption and photoluminescence quenching efficiency,rnrespectively. Hence, this study have shown that despite the high boiling point solventrnadditives, low boiling point solvent additives can improve the phase separation of thernactive layer that in turn enhances charge dissociation and PCE.