Functionalization of spiro[fluorene-9,9′-xanthene] with diketopyrrolopyrrole to generate a promising, three-dimensional non-fullerene acceptor

A spiro[fluorene-9,9′-xanthene], often described as a “low-cost spiro,” has been functionalized with terminal diketopyrrolopyrrole units to generate a promising, three-dimensional non-fullerene acceptor. The new acceptor, coded as SFX1, was readily synthesized using the Suzuki cross-coupling reaction and was sufficiently soluble in a variety of commonly used, film-processing solvents such as chlorobenzene and o-dichlorobenzene. SFX1 displayed promising optoelectronic properties and the HOMO/LUMO energy levels complementary to the commercially available and commonly used donor polymers P3HT and PTB7. The joining of two high-potential building blocks – the spiro[fluorene-9,9′-xanthene] and diketopyrrolopyrrole – demonstrates a new strategy where the device performance [D : A 1 : 1.2 = 9.42% (D = PTB7)] validates its use as a potential, three-dimensional non-fullerene acceptor.