Perovskite solar cells have revolutionized the fabrication of solution-processable solar cells. The presence of lead in the devices makes this technology less attractive, and alternative metals in perovskites are being researched as suitable alternatives. We demonstrate a new type of tin-based perovskite absorber that incorporates both ethylenediammonium (en) and formamidinium (FA), forming new materials of the type {en}FASnI₃. The three-dimensional ASnI₃ structure is stable only with methylammonium, FA, and Cs cations, and the bandgap can be tuned with solid solutions, such as ASnI_3−xBr_x. We show that en can serve as a new A cation capable of achieving marked increases in the bandgap without the need for solid solutions. The en introduces a new bandgap tuning mechanism that arises from massive Schottky style defects. In addition, incorporation of the en cation in the structure markedly increases the air stability and improves the photoelectric properties of the tin-based perovskite absorbers. Our best-performing {en}FASnI₃ solar cell has the highest efficiency of 7.14%, which is achieved for a lead-free perovskite cell, and retains 96% of its initial efficiency after aging over 1000 hours with encapsulation. Our results introduce a new approach for improving the performance and stability of tin-based, lead-free perovskite solar cells.

High-entropy lead chalcogenides usually exhibit high ZT values at a very narrow temperature window because the highly disordered lattice structure trades electrical conductivity for low lattice thermal conductivity (κ_lat). Here, we construct a new entropy-engineered n-type lead chalcogenide of Cu_0.004Pb_1–xSn_xSe_0.5Te_0.25S_0.25 (x = 0 – 0.1). Remarkably, Sn doping plainly fixes the lattice by homogenizing the charge density difference in the vicinity of Cu atoms. This facilitates Cu atoms atomically dispersing into the interstice of the matrix, removing dislocation and nanoscale precipitates that are commonly found in low-entropy lead chalcogenides. The completely dissolved Cu atoms dynamically optimized the carrier concentration over the temperature range of 300 – 723 K. Resultantly, the Cu_0.004Pb_0.99Sn_0.01Se_0.5Te_0.25S_0.25 shows maximum power factor of ~21 μW·cm^–1·K^–2 at 300 K and an average power factor of ~19 μW·cm^–1·K^–2 from 300 – 723 K, rivaling the low-entropy lead compounds with ordered lattice structure. Importantly, the atomically dispersed interstitial Cu atom also markedly shortens the phonon mean free path, suppressing the minimum κ_lat to ~0.2 W·m^–1·K^–1 at 723 K which strikes the theoretical minimum. The synergistically optimized charge and thermal transport properties collectively give rise to a benchmark room temperature ZT of ~0.6, which monotonously increases to ~1.7 at 723 K, surpassing all the n-type entropy-engineered and low-entropy lead chalcogenides.

All‐inorganic metal halide perovskite CsPbBr₃ crystal is regarded as an attractive alternative to high purity Ge and CdZnTe for room temperature γ‐ray detection. However, high γ‐ray resolution is only observable in small CsPbBr₃ crystal; more practical and deployable large crystal exhibits very low, and even no detection efficiency, thereby thwarting prospects for cost‐effective room temperature γ‐ray detection. The poor performance of large crystal is attributed to the unexpected secondary phase inclusion during crystal growth, which traps the generated carriers. Here, the solid–liquid interface during crystal growth is engineered by optimizing the temperature gradient and growth velocity. This minimizes the unfavorable formation of the secondary phase, leading to industrial‐grade crystals with a diameter of 30 mm. This excellent‐quality crystal exhibits remarkably high carrier mobility of 35.4 cm² V⁻¹ s⁻¹ and resolves the peak of ¹³⁷Cs@ 662 keV γ‐ray at an energy resolution of 9.91%. These values are the highest among previously reported large crystals.

Secondary Nb₁₈W₁₆O₉₃/C micro-grade particles are synthesized for use as a fast-charging anode with high stability and rate performance at 5C.

Flexible CsPbBr ₃ film is facilely prepared through an improved electrospraying method. Highly crystalline film and efficient X-ray detection are acquired by optimizing the solvent system and crystal growth temperature.