A new class of Ca5Ga6O14:Tb3+ mechanoluminescent phosphors with trap-independent, self-recoverable mechanoluminescence and a low mechanical stimulus threshold are reported, whose properties originate from piezoelectricity of the host with giant piezoelectric coefficients.

Fine control of photon emission of Eu2+ activated luminescent materials is essential for advanced optoelectronic applications. However, it remains difficulty to design blue light excitable Eu2+ doped oxide red phosphor...

Herein, the self‐reduction behavior of manganese (Mn) in Mg2SnO4 (MSO) host lattices prepared by using the solid‐state reaction technique in air atmosphere is reported. Excited by 282 nm, only the emission of Mn2+ is seen, and the observed results are confirmed by theoretical calculation based on the density functional theory. Noteworthy, with the codoping of Li+, the self‐reduction process of Mn is suppressed, leading to the coexistence of Mn2+ and Mn4+ in MSO host lattices along with the multicolor emissions. For the suppressed self‐reduction behavior, possible hypotheses are proposed to elucidate the corresponding mechanisms. Furthermore, benefiting from the different thermal quenching behaviors of Mn2+ and Mn4+, ratiometric optical thermometers with high sensitivity of 6.59% K−1 are designed. Moreover, the prepared phosphors possess a good green afterglow phenomenon, in which their trap depth are 0.71 and 0.91 eV. In addition, via using the designed phosphors, applications in anti‐counterfeiting, fingerprint identification, and optical information storage are also realized.

Optical thermometry offers promising application in the microelectronic and biomedical fields, as well as fire pre-warning systems. In this research, Pr3+ activated SrZn0.33Nb0.67O3 phosphors were successfully prepared via solid-state reactions....

Herein, the nucleation, growth, aggregation, sintering, and densification of sulfide in 1215MS free-cutting steel billet with a total oxygen concentration of 70 ppm are investigated. A portion of oxygen in the steel dissolves in sulfide to form oxysulfide, Mn(S,O), which can be single-particle spherelike (SPS), doubleparticle rodlike (DPR), and multi-particle rodlike (MPR), and SiO 2 can precipitate at the outer edge of the SPS and connection in the DPR and MPR inclusion particles to form Mn(S,O)-SiO 2 inclusion, which is formed by the change of liquid inclusion, that undergoes monotectic reaction to form oxides and oxysulfide. The possible phase-transition process can be expressed as (Mn,Si) x (S, O) y (l) ! Mn(S,O)(l ! s) þ (Mn,Si) x O y (s) ! Mn(S,O)(s) þ SiO 2 (s). Oxysulfide inclusions can aggregate under the influence of van der Waals and viscous drag forces. The larger the particle, the greater the critical spacing and aggregation force. MPR oxysulfide can be divided into three parts: droplet, flat surface, and neck, which have decreasing chemical potentials in turn. Sintering and densification occur after the aggregation of particles, where surface diffusion of elements dominates, while grain boundary diffusion and bulk diffusion dominate in the densification of particles. Meanwhile, the formation and evolution of five different morphologies of sulfides in 1215MS free-cutting steels are discussed.