High-performance polymer solar cells with a conjugated zwitterion by solution processing or thermal deposition as the electron-collection interlayer

Abstract

We report highly efficient polymer solar cells (PSCs) with rhodamine 101, a conjugated zwitterion with positive and negative charges on the same molecule, as the electron-collection interlayer. Rhodamine 101 can be processed by solution processing techniques or thermal deposition. The rhodamine 101 interlayer simultaneously improves the short-circuit current, open-circuit voltage, fill factor so as to improve the photovoltaic efficiency of the PSCs with poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3- benzothiadiazole-4,7-diyl-2,5-thiophenediyl] (PCDTBT) and [6,6]-phenyl-C71- butyric acid methyl ester (PC 71BM) as the active materials in comparison with control PSCs wit..