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Bismuth halide perovskites have recently been considered a potential alternative to lead halide analogues due to their low toxicity and high stability. However, the layered flake structure and wide band gap limit their applications in perovskite solar cells (PSCs). We herein show that large-grained allinorganic bismuth-based perovskites with a narrow band gap can be obtained from a Lewis acid−base adduct reaction under ambient conditions. Thiourea (CH 4 N 2 S) is utilized as a Lewis base to interact with BiI 3 , confirmed with infrared (IR) spectra. The strong coordination between thiourea and the Bi 3+ center could slow down the perovskite crystallization and promote the preferred orientation of the perovskite crystals with a hexagonal phase. The morphology of the perovskite films varies dramatically with an increase of molar ratio of BiI 3 and thiourea in the precursor. The perovskites derived from a BiI 3 /thiourea ratio of 1:2 display extrathick grains, higher surface coverage, extended light absorption, higher crystallinity, and similar air stability compared to the pristine sample. The power conversion efficiency (PCE) of the thioureainduced bismuth perovskite solar cells is significantly enhanced due to the higher surface coverage and the broader absorption of the perovskite film.

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One-dimensional (1D) TiO2 nanowire arrays are fabricated on transparent conducting substrates via a low temperature hydrothermal route for application in dye-sensitized solar cells (DSSCs). The as-prepared sample on fluorine-doped tin oxide (FTO) substrate is found to be single-crystalline rutile TiO2 structures from X-ray and electron diffractions. The length and diameter of the nanowires depend mainly on the growth time and temperature. With increasing the reaction time, the growth rate becomes slower and the interface adhesion between the growth nanowires and the substrate becomes weaker. In the same time the adjacent nanowires aggregate to larger the apparent diameter of the nanowire making the gaps among the nanowires to disappear at last. The nanowires exhibit flower-like morphology on the non-conducting surface of FTO substrate. By using TiO2 nanowire arrays with 2 microm long on FTO substrate as the photoanode in DSSCs, an overall light conversion efficiency of 1.58% is achieved with an open circuit voltage of 0.714 V, a short circuit current density of 4.68 mA cm(-2), and a fill factor of 0.472.

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The present study reports a novel method for a direct growth of one‐dimensional (1D) TiO2 nanoarchitectures on fluorine‐doped tin oxide (FTO) conductive glass by a heterogeneous solvothermal route. Results indicate that the morphologies of the obtained samples can be controlled and changed from vertically oriented single‐crystalline rutile nanowire arrays to randomly disoriented nanotubular architectures by controlling the position of the substrate and the amount of the initial precursor. At a low concentration of the precursor, dandelion‐like TiO2 comprised of large amounts of the crystalline nanorods are found on the nonconductive surface of the horizontally oriented FTO glass, which are suitable for photocatalysis, while TiO2 nanowire arrays are grown on the conductive surface of the FTO glass, which can be used as photoanodes for sensitized solar cells to enhance the electron‐transport rate. The difference in morphology is probably related to the selective adsorption of the Cl ions, the texture of the substrate, and the immiscibility between the nonpolar solvent and the aqueous solution.