Near-infrared response photovoltaic device based on novel narrow band gap small molecule and PCBM fabricated by solution processing

In this paper, we report on synthesis of a novel diphenylaminofluorenyl-capped thiadiazoloquinoxaline (6,7-dimethyl-4,9-di{5-[9,9-bis(octyl)-7-diphenylaminofluorene-2-yl]-4-hexylthien-2-yl}[1,2,5]-thiadiazolo[3,4-g]quinoxaline (DPAFL-TDOX-DPAFL which is further abbreviated to TDOX), Scheme 1) and its use as donor material for the realization of efficient bulk-heterojunction organic solar cell by spin coating from blend with PCBM as acceptor. TDOX showed very good solution processibility and film uniformity up to weight ratio TDOX:PCBM=1:4. Spectral response was extended to near-infrared region (at around 1000 nm) with energy conversion efficiency (ECE) 0.75% and short-curcuit current density 1.95 mA/cm2.