Organic and polymer photovoltaic cells are becoming an extremely active research area to meet the urgent need for clean and renewable energy managements due to their potential applications as flexible

low cost and solution processable energy sources. In this article

the influence of introducing a small amount of NPB into the mixed P3HT:PCBM solution on the performance of the polymer solar cells was investigated. It was found that adding NPB improved bulk heterojunction grown which enhanced the photovoltaic performance. When NPB content is 0.4mg/mL

PCE increased from 1.05% to 1.64%. The UV-Vis absorption spectra showed that the intensities of the absorption peaks at 560 and 610 nm increased because of the increased absorption π→π* transition of P3HT after adding NPB. SEM results also showed that the P3HT:PCBM phase separation increased markedly after adding NPB which is valuable for exciton dissociation. It was found that the hole mobility could be pronouncedly influenced by adding NPB.