Synthesis of p-type small molecule hole transport material for colloidal quantum dot solar cells

Abstract

We designed and synthesized a acceptor-donor-acceptor (A-D-A) structured conjugated small molecules, 7, 7'- ((4,8-bis((2-ethylhexyl)oxy)benzo [1,2-b:4,5-b'] dithiophene-2, 6-diyl) bis (4 octylthiophene-5, 2-diyl)) bis (4-(4-octylthiophen-2-yl) benzo [c] [1,2,5] thiadiazole) (BDTTBT), and applied as hole transport layer (HTL) for colloidal quantum dot solar cells (CQDSCs). The BDTTBT based device achieved the highest PCE (8.47%) among the reported CQDSCs using SM HTLs, and also higher than the conventional P3HT based devices (7.60%).