Influence of the Electron Acceptor Group on the Backbone of N-(2,6-Diisopropylphenyl)-2,5-di(2-thienyl)pyrrole-Based Polymer

Development of structurally new polymers for polymer solar cell (PSC) applications is an attractive research area due to their beneficial properties such as clean energy production, low-cost, light-weight, and roll-to-roll process-ing on flexible substrates.1 The power conversion efficiency (PCE) of the PSCs was finally improved to 7.0-8.6 % by utilizing suitable polymers as electron donor materials, that have the appropriate energy levels with efficient light harvesting ability, and PC71BM as an electron accepting material.2-8 In our laboratory, we have been interested in preparing N-(2,6-diisopropylphenyl)-2,5-di(2-thienyl)pyrrole (N-aryl TPT)-based π-conjugated polymers as electron donor materials for PSC applications. Recently, we reported several N-aryl TPT-based polymers containing electron rich units such as indenofluorene (PIFTPT),9 2,5-dioctyloxy