Random double-cable conjugated polymers with controlled acceptor contents for single-component organic solar cells

Abstract

Double-cable conjugated polymers contain electron-donating (D) backbones and electron-accepting (A) side units, in which the nanophase separation of the donor and acceptor segments is a crucial factor to determine the photovoltaic performance of single-component organic solar cells (SCOSCs). In this work, three random double-cable conjugated polymers (denoted as P1–P3 with enhanced acceptor contents) have been designed to tailor the nanophase separation of D/A to realize high-performance SCOSCs. These new random double-cable conjugated polymers contain identical polymer backbones with varied contents of near-infrared acceptor side units. It is observed that the acceptor contents could effectively tune the aggregation degree of the backbone and acceptor (shown in the absorption spectra and grazing-incidence wide-angle X-ray scattering measurement) and further influence the construction of charge-transporting pathways. Therefore, a moderate content of acceptor side units provides balanced D/A aggregation and optimal nanophase separation, resulting in a high efficiency of 9.4% in SCOSCs. These results demonstrate that random double-cable conjugated polymers are an excellent model for studying the impact of their aggregation/crystallinity so as to realize high-performance SCOSCs.