Energy-effectively printed all-polymer solar cells exceeding 8.61% efficiency

Journal article, 2018

All-polymer solar cells (all-PSCs) have attracted tremendous attention in the past few years due to their unique advantages. However, up to now most of high-efficiency all-PSCs are processed by spin-coating with complicated post treatment processes, which is ill-suited to a large-area roll-to-roll (R2R) technique. In this work, high-efficiency all-PSCs based on PTB7-Th and PNDI-T10 are achieved by one of R2R compatible printing techniques, i.e. doctor-blading, without any annealing treatment. It was found that incorporating an additive into all polymer blends solution can prolong the drying time of all polymer nanocomposites from 120 to 1000 s to form a better bulk heterojunction morphology and a higher crystallinity, which thus reduce charge recombination and show much better electrical impedance spectroscopy parameters. Record-breaking power conversion efficiencies (PCEs) of 8.61% and high fill factors (FF) of 0.71 are achieved by doctor-blading under an extremely process-simple and energy-effective conditions. Moreover, large-area (2.03 cm 2 ) flexible ITO-free all-PSCs by doctor-blading with record-breaking PCEs of 6.65% and FF of 0.65 are realized, which are much higher than conventional fullerene-based ones under the same condition, demonstrating that all-PSCs are more suitable for the flexible device structure and have a bright future towards practical application with R2R manufacture.