Perovskite
solar cells (PSCs) have achieved boosted efficiency
growth in the last decade by utilizing 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene
(spiro-OMeTAD). Various dopant-free small molecules and polymers were
introduced as hole-transporting materials (HTMs) to revamp the drawbacks
of spiro-OMeTAD such as poor stability, high cost, and sophisticated
processing. Herein, a polymer showing enhanced π-conjugation,
trithiophene-benzene (TTB), was put forward through molecular engineering
by further modifying the previously reported HTM [2,4-dithiobiuret
(DTB)]. One more thiophene was embedded into the main chain to increase
the exposure of sulfur atoms to perovskite, as well as to enhance
the conjugation effect. The continuously maintained π–π
stacking guarantees smooth hole extraction from the perovskite layer.
TTB-based PSCs not only show a high power conversion efficiency (PCE)
of 18.2% in high-level devices with dopant-free organic HTMs but also
demonstrate outstanding ambient stability, retaining 91.1% of their
initial PCE after 30 days of storage.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.