Broadband Absorbing Bulk Heterojunction Photovoltaics Using Low-Bandgap Solution-Processed Quantum Dots

Abstract

We describe bulk heterojunction (BHJ) solar cells containing blends of colloidal PbS nanocrystal quantum dots with several new donor acceptor conjugated polymers Using photoinduced absorption spectroscopy we found that blends of PbS quantum dots with one polymer, poly(2,3-didecyl-quinoxaline-5,8-diyl-alt-N-octyldithieno[3,2-b.2’,3’ ‘-d]pyrrole) (PDTPQx), produce significantly more photoinduced charge than blends of PbS with the other donor acceptor polymers or with traditionally studied polymers like (2-methoxy-5-(3’,7’-dimethyloctyloxy)-para-phenylene vinylene) (MDMO-PPV) and poly(3-hexylthiophene) (P3HT) Photovoltaic devices made with PDTPQx/PbS blends exhibit power conversion efficiencies 10-100 times larger than previously reported BHJ blends made with IR-absorbing quantum