The power factor was significantly enhanced benefiting from texture modulation, resulting in a ZT of ∼1.0 in p-type polycrystalline SnSe.

Research progress in alkali metal ion (Li+, Na+, K+ and Rb+) doped perovskite solar cells is summarized and evaluated.

SnO2 and F doped SnO2 (FTO) nanoparticles (NPs) have been synthesized by the hydrothermal method with subsequent annealing at 500 °C. The microstructure and photoluminescence (PL) property of SnO2 and FTO NPs have been investigated, and an assumption model about the luminescence process of FTO NPs has been proposed. All of the SnO2 and FTO NPs possess polycrystalline tetragonal rutile structures, and the average size in the range of 16.5–20.2 nm decreases with the increasing of F doping content. The doping element F is shown a uniformly distribution by electron energy loss spectroscopy (EELS) mapping. The oxygen vacancy concentration becomes higher as is verified by Raman and X-ray photoelectron spectra (XPS). There are three kinds of oxygen chemical states in SnO2 and FTO NPs, in which Oα corresponds to oxygen vacancies. The room temperature PL position is observed to be independent of F doping content. F− may substitute O2− into the SnO2 lattice by generating FO+ and one extra e−, which can combine with VO+ or VO++ to generate VO0 or VO+ to ensure charge balance.

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