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Reduced toxicity and better atmospheric stability have made the Cs2AgBiBr6double-perovskite material a promising photo-absorbing material to replace lead halide-based perovskites in solar photovoltaic applications. In this work, for the first time, a novel low-temperature method for the synthesis of lead-free Cs2AgBiBr6double-perovskite ink, using a salt solution of the constituents of Cs2AgBiBr6at a temperature of as low as 50°C, is reported. An X-ray diffraction study confirmed the presence of the Cs2AgBiBr6double-perovskite crystal structure, and an ultraviolet–visible absorption study was done to calculate the band gap. Particle size analysis showed that the particle size of the prepared ink lies in the range 700–1000 nm, and scanning electron microscopy was done on a spin-coated substrate to examine the microstructural features of the ink. The present work will help develop further a low-cost and simple method for the development of double-perovskite ink.

Interlayers and interface engineering plays a pivotal role in achieving efficient charge extraction necessary for realizing high power conversion efficiency (PCE) in bulk heterojunction organic solar cells. In this study, we report a novel strategy of combining advantages of both fullerene derivative and non-fullerene acceptor materials by employing solution processable non-fullerene acceptor 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indan-one))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2’,3’-d’]-s-indaceno[1,2-b:5,6-b’]dithiophene (ITIC) to modify the interface between ZnO-based electron transport layer and poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl) benzo [1,2-b;4,5-b'] dithiophe-ne-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carb-oxylate-2-6-diyl)] (PTB7-Th): phenyl-C71-butyric acid methyl ester-based photoactive layer. An improvement in PCE from ∼ 7.5% to ∼ 9% has been achieved for the devices with ITIC modified interlayer. Time resolved photoluminescence (PL) via time correlated single photon counting and photo-electrochemical impedance spectroscopy (photo-EIS) measurements were carried out to investigate the causes for improved PCE for the devices with ITIC modified interlayer.