Diketopyrrolopyrrole-Based Semiconducting Polymer for Photovoltaic Device with Photocurrent Response Wavelengths up to 1.1 μm

A highly effective photovoltaic polymer with near-infrared response, poly{N-[1-(2-ethylhexyl)-3-ethylheptanyl]-dithieno[3,2-b:2′,3′-d]pyrrole-3,6-dithien-2-yl-2,5-dibutylpyrrolo[3,4-c]pyrrole-1,4-dione-5′,5′′-diyl} {PDTP-DTDPP(Bu)}, was synthesized. The polymer has high molecular weight, good solubility, and a broad absorption spectrum in the range of 500−1100 nm. Field effect transistor charge mobility of PDTP-DTDPP(Bu) arrived 0.05 cm2 V−1 s−1. Bulk heterojunction type polymer solar cells based on PDTP-DTDPP(Bu) and PC70BM have broad photocurrent response wavelength range from 300 nm to 1.1 μm. High short-circuit current (14.87 mA/cm2) and power conversion efficiency (2.71%) were achieved, which is a significant advance for efficient photovoltaic polymers that respond to the whole range of the solar spectrum.