Extensive research on organic photovoltaics has granted impressive power conversion efficiencies, nowadays exceeding 13% for state-of-the-art photoactive material combinations. Nevertheless, different strategies can be adopted to further enhance the efficiency and the competitiveness with alternative photovoltaic technologies. Conjugated polyelectrolytes have been applied as anode or cathode interlayers to optimize ohmic contacts and lower the contact resistance, thereby improving the ultimate device efficiency. Here, we present an interlayer material belonging to the emerging class of narrow bandgap conjugated polyelectrolytes, based on an imidazolium functionalized 4H-cyclopenta[2,1-b:3,4-b']dithiophene (CPDT) as the electron-rich polymer building block and 4H-thieno[3,4-c]pyrrole-4,6(5H)-dione (TPD) as the electron-deficient subunit. The ionic polymer is applied as cathode interlayer for PBDTTPD:[70]PCBM (poly[bis(2′-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene-alt-N-octylthieno[3,4-c]pyrrole-4,6-dione]:[6,6]-phenyl-C₇₁-butyric acid methyl ester) bulk heterojunction polymer solar cells, improving the overall device performance from 6.9 to 7.8%.

对有机光伏的广泛研究已经赋予了令人印象深刻的功率转换效率，如今，对于最先进的光敏材料组合，其转换效率已超过13％。然而，可以采用不同的策略来进一步提高替代光伏技术的效率和竞争力。共轭聚电解质已被用作阳极或阴极中间层，以优化欧姆接触并降低接触电阻，从而提高了最终的器件效率。在这里，我们介绍一种基于咪唑官能化的4 H-环戊[2,1- b：3,4- b']二噻吩（CPDT）作为富电子的聚合物结构单元，4 H-噻吩并[3,4- c ]吡咯-4,6（5 H）-二酮（TPD）作为缺电子的亚基。所述离子聚合物加到作为阴极PBDTTPD夹层：[70] PCBM（聚[双（2'-乙基己氧基）苯并[1,2- b：4,5- b '] dithiophene- ALT - ñ -octylthieno [3， 4 - c ]吡咯-4，6-二酮]：[6,6]-苯基-C _71-丁酸甲酯）本体异质结聚合物太阳能电池，将整体器件性能从6.9提高到7.8％。