All-inorganic metal halide perovskite semiconductors have great potentials in lighting applications, but the effect of excitonic magnetic polarons (EMPs) in the transition metal (TM) ion-doped halide perovskites on their luminescence processes has not been extensively understood. Here, we have synthesized Mn2+-doped Rb3Cd2Cl7 perovskite powders with different doping amounts by a hydrothermal method. After Mn(II) is doped, Rb3Cd2Cl7 gives strong emission, though the Rb3Cd2Cl7 powder itself does not emit light. This emission originates from the intrinsic self-trapped exciton (STE) formation enhanced by the ferromagnetic Mn–Mn pair with spin–spin coupling, that is, the magnetic polaron whose astonishing luminescence at 587 nm has a quantum yield up to 147%. Some shallow trapped centers below the conduction band out of high d levels by localized EMPs after photoexcitation are proven to add to this luminescence process. The thermoluminescence phenomenon with rising temperature proves that these shallow trapped carriers are present with phonon and multiphonon notation, and their efficient transfer to the conduction band and the STE state occurs via the electron–phonon coupling during photoexcitation. This compound provides a new way for TM-doped perovskite material design and applications for magneto-optical and display technology.
Xin Jiang,Weilong Zhou,Wen Dong,Zhu Wang,Yifei Xie,Xinyue Tang,Zichun Le
Laser speckle caused by high coherence severely affects the image quality. The traditional optical approaches cannot effectively suppress speckles without compromising the coherence of the laser in the optical path. In this study, we develop a method in which a novel polymer-stabilized liquid crystal screen (PSLCS) was used to display images for efficient speckle suppression while preserving the coherence and high brightness of lasers. The scattering-induced fluctuations in the intensity of the light reflected from the PSLCS are evaluated to reveal decorrelation variation. The optimal parameters for suppressing speckles and obtaining a clear and high-resolution image via both laser projection and AR imaging are identified by adjusting the driving parameters. A speckle suppression efficiency of 67.34%, which exceeds that achieved by other similar methods, was achieved without using any additional optical elements. An experiment was implemented for verifying the performance of multi-plane AR imaging by a PSLCS, which, to our knowledge, is the first study to investigate the image quality and speckle suppression effect in AR imaging. The proposed cost-effective laser speckle suppression method enables high quality imaging, offering new possibilities for the application of LC-based optical materials and devices in display technology.
危险品化学品经营许可证（带存储）