Efficient Non-Fullerene Organic Photovoltaic Modules Incorporating As-Cast and Thickness-Insensitive Photoactive Layers

In this work, a new combination of a wide bandgap polymer poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']-dithiophene-alt-N-(2-hexyldecyl)-5'5-bis[3-(decylthio)thiophene-2-yl]-2'2-bithiophene-3'3-dicarboximide] (PBTIBDTT) and a non-fullerene small molecule acceptor based on a bulky seven-ring fused core (indacenodithieno[3,2-b]thiophene) end-capped with 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile groups with one fluorine substituent (ITIC-F) is proposed, and as-cast non-fullerene organic solar cells (NFOSCs) with 11.2% efficiency are achieved. The device efficiencies are also insensitive to the variation of photoactive layer (PAL) thickness and can maintain over 9% efficiency as PAL thickness increases to 350 nm, which is one of the best results for as-cast organic solar cells. More importantly, non-fullerene organic photovoltaic (OPV) modules are demonstrated via laser ablation technique for the first time, which delivers a record efficiency of 8.6% (with active area of 3.48 cm(2)) among large-area OPV modules. Furthermore, the morphology and performance evolutions of the as-cast NFOSCs and the ones processed with solvent additive are systematically investigated. The results demonstrate the great advantage of as-cast solar cells in achieving constant morphology and high performance with thick PALs. The NFOSCs fabricated with simple procedure, insensitive to film thickness and compatible with large-area OPV modules, show significant potential for application the future.