It is of great difficulty to obtain deep-UV transparent materials with enhanced second harmonic generation (SHG), mainly limited by the theoretically poor transparency of these materials in the deep-UV spectral region. Here we report a new noncentrosymmetric, deep-UV transparent phosphate RbNaMgPO, which undergoes a thermo-induced reversible phase transition (at a high temperature of 723 K) and correspondingly an evident SHG enhancement up to ∼1.5 times. The phase transition is aroused by the twist of [PO] dimers with deviation from the P-O-P equilibrium positions. Theoretical analyses reveal that the enhanced SHG can be ascribed to the thermo-induced collective alignment of SHG-active [PO] dimers along the polar axis of high-temperature phase. This work provides an unprecedented physical routine (to SHG-enhanced materials) that is distinguished from the traditional one by chemical design and synthesis.

Lead-free zero-dimensional (0D) organic−inorganic metal halide hybrids have recently attracted special attention as luminescent materials. However, their structural stability is still a challenge for the further development. Here, we select Sn 4+ as the B-site inorganic cation and obtain a new tin(IV)-based organic−inorganic metal halide hybrids (C 6 N 2 H 16 Cl) 2 SnCl 6 with remarkable air stability. (C 6 N 2 H 16 Cl) 2 SnCl 6 exhibits a blue broadband emission originating from self-trapping excitons (STEs) and the emission intensity remains stable for over three months. When the temperature rises to 450 K, the intensity of photoluminescence can maintain about 50%, indicating the good thermal stability of (C 6 N 2 H 16 Cl) 2 SnCl 6 . This work presents a new strategy toward the tin(IV)-based photoluminescent organic−inorganic metal halide hybrids with environmentally friendly, high stability characteristics.

Cubic perovskite SrCoO3−δ was successfully prepared through simple anion F-doping and demonstrated great OER performance.