Novel Red Mechanoluminescence in Mn‐Doped ZnGa₂S₄ Crystal Phosphors via a Molten Salt Shielding Method

Abstract

Owing to their unique characteristic of direct mechanical‐to‐optical energy conversion, mechanoluminescence (ML) crystals have drawn considerable interest for visible stress sensing, flexible and stretchable displays, and advanced anti‐counterfeiting. However, among the visible emissions of synthetic ML materials, high‐performance red‐emission semiconductors with ideal color‐rendering indices are relatively scarce, which restricts their future applications. In this work, red ML emission with CIE coordinates (0.6395 and 0.3572) in Mn‐doped ZnGa2S4 prepared by a molten salt shielding synthesis method in the air is reported. ZnGa2S4 has a cubic crystal structure composed of a layered [ZnS4] tetrahedral unit that plays an important role in efficient ML. Based on density functional theory calculations, the relationship between ML performance and crystal structure is revealed, which will help in the development of new high‐quality ML materials. The Mn‐doping of ZnGa2S4 causes a slight deformation of the crystal structure, leading to band bending and the formation of ML features in response to mechanical stimuli. The deep‐red ML emission of the ZnGa2S4:Mn crystals prepared by this method holds great promise for advanced flexible and stable displays and force/pressure sensor applications.

Molten Salt Synthesized CaTa4O11:Er3+/Yb3+ with Superior Upconversion Luminescence

“…MSS can effectively control the growth of particles and crystallization of materials and avoid particle agglomeration occurring during SSR. Moreover, researchers have developed new MSS-based preparation methods, such as the molten salt shielding method and coprecipitation/molten salt two-step synthesis method, which can prepare sulfides and oxysulfides, , nonoxide ceramics, oxide nanoparticles, − etc. Reports on synthesis of ternary layer tantalates by MSS mainly include Cu 5 Ta 11 O 30 and Cu 3 Ta 7 O 19 with CuCl flux, , Pb 1.5 Ta 7 O 19 , PbTa 4 O 11 , and Pb 3 Ta 4 O 13 with Na 2 SO 4 , K 2 SO 4 , and PbCl 2 flux, , and Na 2 Ta 4 O 11 with Na 2 SO 4 and K 2 SO 4 flux .…”

Enabling Multimodal Luminescence in a Single Nanoparticle for X-ray Imaging Encryption and Anticounterfeiting

“…At a relatively low force, the ML may be ascribed to the triboelectric effect. − The increase of applied forces would distort the host lattice and raise the piezoelectric potential of the host dramatically, resulting in a rapid enhancement of the ML intensity (Figures S8 and S9; Table S1). − It was reported that piezoelectricity in noncentrosymmetric structures is significantly stronger than triboelectricity, , and the distortion index in the hexagonal phase is indeed much higher than that in the cubic phase (Table S2). Figure g shows the ML repeatability of the samples.…”