Abstract
The work-function of indium tin oxide (ITO) electrodes was tuned with an interfacial dipole layer (WPF-oxy-F) to reverse the polarity in polymer solar cells (PSCs) with an inverted structure. The photoactive layer was based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). Silver (Ag) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) were used as the top anode. The optimized conditions for the fabricated I-PSCs included an open-circuit voltage (Voc) of 0.68V, a fill factor (FF) of 64%, and a power conversion efficiency (PCE) of 3.86% through post-annealing at 170°C. The high performance of I-PSC is due partly to the improved interfacial contact at active/PEDOT:PSS and mainly to the increase of the work-function of annealed PEDOT:PSS/Ag at 170°C for 30min. Here, we investigated the effect of post-annealing on I-PSC devices by carrying out various annealing sequences.
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•Conjugated polyelectrolyte was used as an electron selective layer in inverted polymer solar cells.•The post-annealed devices at 170°C shows optimized efficiency of 3.86%.•We carried out various annealing sequences to investigate the effect of post-annealing on devices.