A series of crosslinked diphenylamine derivatives have been developed and employed as hole transport materials in inverted p–i–n planar perovskite solar cells, which exhibit the significantly improved device efficiency and stability.

To develop novel hole-transport materials (HTMs) with less synthetic steps is still a great challenge. Here, a small molecule hexakis[4-(N,N-di-p-methoxyphenylamino)phenyl]benzene (F-1) was successfully synthesized by a relatively simple scenario. F-1 exhibits a deep highest occupied molecular orbital energy level of -5.31 eV. Notably, F-1 also features 2 times higher hole mobility of 4.98 × 10 cm V s than that of the mostly used 2,2',7,7'-tetrakis(N,N-bis(4-methoxyphenyl)amino)-9,9'-spirobifluorene (spiro-OMeTAD). Consequently, F-1-based perovskite solar cells (PSCs) show markedly improved performance compared with spiro-OMeTAD-based ones. These results indicate such a material can be a promising HTM candidate to boost the overall performance of the PSC.

Two novel anionic conjugated copolyelectrolytes PSDPPPV and PSDPPPE were synthesized via Heck/Sonogashira coupling reactions and characterized by FT-IR, 1 H NMR, UV-vis, and PL spectroscopy. The two polymers are respectively constituted of 2,5-diethoxy-1,4-phenyleneethynylene (DPV) and 2,5-di ethoxy-1,4-phenyleneethynylene (DPE) with 1,4-diketo-2,5-bis (4-sulfonylbutyl)-3,6-diphenylpyrrolo[3,4-c]pyrrole (SDPP) which is a novel water soluble diketopyrrolopyrrole derivative. PSDPPPV and PSDPPPE show broad absorption band in visible region and they exhibit strong fluorescence quenching in aqueous solution. The fluorescence of their aqueous solutions can be enhanced in the presence of cationic surfactant or polymer non-ionic surfactant. Fluorescence enhancement by introduction of polyvinylpyrrolidone (PVP) shows linear response. This result provides a controllable method to increase fluorescence intensity of dipyrrolopyrrole-based conjugate polyelectrolytes in aqueous phase. The optical properties suggested that PSDPPPV and PSDPPPE which are negatively charged conjugated polymers can assemble with positively charged photovoltaic materials to form ionic photoactive layer.

Efficient hysteresis elimination and significant performance improvement are achieved by interfacial modification with a thermo-cleavable fullerene derivative.

Bismuth-halide-based perovskites could be promising candidates for construction of lead-free and air-stable perovskites solar cells. Herein we report a simple strategy on the fabrication of the Ag 3 BiBr 6 thin films. They were prepared by flexible spin-coating procedure and the solvent of N-butylamine is found to be critical to dissolving AgBr precursor solution under lower room temperatures. Experiment and calculation analysis both reveal it with hexagonal structure. Their physical properties and photovoltaic performance were both characterized. We demonstrate that Ag 3 BiBr 6 films are capable of storing stably over 30 days in air. These results will inspire more research works on developing and applying Ag 3 BiBr 6 beyond solar energy applications.