Tin‐based perovskite solar cells (PSCs) demonstrate a potential application in wearable electronics due to its hypotoxicity. However, poor crystal quality is still the bottleneck for achieving high‐performance flexible devices. In this work, graphite phase‐C3N4 (g‐C3N4) is applied into tin‐based perovskite as a crystalline template, which delays crystallization via a size‐effect and passivates defects simultaneously. The double hydrogen bond between g‐C3N4 and formamidine cation can optimize lattice matching and passivation. Moreover, the two‐dimensional network structure of g‐C3N4 can fit on the crystals, resulting an enhanced hydrophobicity and oxidation resistance. Therefore, the flexible tin‐based PSCs with g‐C3N4 realize a stabilized power conversion efficiency (PCE) of 8.56 % with negligible hysteresis. In addition, the PSCs can maintain 91 % of the initial PCE after 1000 h under N2 environment and keep 92 % of their original PCE after 600 cycles at a curvature radius of 3 mm.

Fullerene end-capped polyethylene glycol (C60-PEG) was introduced via an antisolvent method to fabricate the perovskite films. C60-PEG could enlarge the perovskite crystal size and passivate the defects of perovskite films, facilitating the carrier transport and hindering the carrier recombination. In consequence, the superior optoelectronic properties were attained with an improved power conversion efficiency of 17.71% for the perovskite device with C60-PEG treatment. Meanwhile, amphiphilic C60-PEG enhanced the resistance of perovskite films to moisture. After 40 days, the C60-PEG-based devices without encapsulation remained 93 and 86% of the original power conversion efficiency value under nitrogen and ambient conditions (25 °C temperature, 60% humidity), respectively.

The inevitably interfacial defects in the under layer of perovskite films still trouble the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs), especially for large-area flexible devices...

A novel triple dipole effect has been observed for Cl-assisted self-assembled small-molecules on ITO substrate, and a highest polymer solar cell performance of 9.2% is obtained.

Cerium oxide, solution processed at a low temperature (∼100 °C), was successfully employed as an electron extraction layer on top of a perovskite. The CeO layer shows good charge selectivity and increases light reflection from an Ag electrode. Besides this, the CeO layer not only protects the perovskite from water, but also acts as a dense diffusion barrier to prevent the corrosion of the metal electrode.