Structure-performance correlation of indacenodithiophene-based narrow band-gap polymers with pendant diketopyrrolopyrrole units

Two novel indacenodithiophene based narrow band-gap polymers (PIDT-BDTDPP and PIDT-TDPP) with pendant DPP units onto different main chains were synthesized. The PIDT-TDPP with pendant DPP units onto thiophene units exhibited better light-harvesting properties and charge transport properties. While the PIDT-BDTDPP with pendant DPP units onto BDT units displayed lower the highest occupied molecular orbital energy levels. Notably, the PIDT-TDPP-based PSCs shown a power conversion efficiency (PCE) of 3.62%. The PCE level is 1.88 times higher than that in the PIDT-BDTDPP-based PSCs.202