A transparent ferroelectric 0.75Pb(Mg 1/3 Nb 2/3 )O 3 -0.25PbTiO 3 :0.015Pr 3+ ceramic was synthesized and its temperature-sensing ability was investigated based on the fluorescence intensity ratio (FIR) method. The transparency was found to be of the order of 68% at 900 nm for a sample thickness of 0.7 mm, comparable to the theoretical value of ~71%, benefiting the photoluminescence of the Pr 3+ ions inside the ceramic. Instead of the traditional Boltzmann exponential style and varying sensitivity, a highly linear temperature response was obtained for the studied ceramic. Further, a constant FIR sensitivity of 0.70 %K -1 was achieved over the temperature range of -50–40 °C, making the ceramic suitable for thermometry at room temperature and below.
Deep ultraviolet (UV) mechanoluminescence (ML) materials hold broad application prospects in bright-field visualization detection, solid-blind imaging, and information storage due to their shorter emission wavelengths. However, current research on deep UV ML materials primarily focuses on trap control to suppress their reuse. Here, we enhance the deep UV ML of Gd 3+ ions by constructing a 4f-5d coupling between Pr 3+ ions and the 6 P 7/2 energy level of Gd 3+ ions in the wide-bandgap Lu 3 Al 2 Ga 3 O 12 with a garnet structure. The results suggest that the deep UV ML in Lu 3 Al 2 Ga 3 O 12 : Pr 3+ , Gd 3+ is trap-independent, and its self-recovery property originates from the continuous triboelectric charge transfer between polydimethylsiloxane and the ML particles. Sterilization experiments using deep UV ML against pathogenic E. coli highlight the potential of deep UV ML materials for continuous sterilization applications.
Chong Zhao,Yingkui Li,Wanggui Ye,Xiaofei Shen,Zicheng Wen,Xuanyi Yuan,Yongge Cao,Chaoyang Ma
Colloidal all-inorganic lead halide perovskite nanocrystals (LHP NCs) feature with tunable high-efficiency photoluminescence from blue to red for optoelectronic applications but suffer from instability under water moisture, UV light illumination, high-temperature shock, as well as oxygen erosion. Previous work to improve LHP NCs stability was mainly focused on either glass bulk sealed LHP quantum dots (QDs) with low quantum efficiency, or mesoporous silica matrixes confined LHP QDs with organic ligands still existing. Here, a facile, noncolloidal, ligand-free LHP QDs growth with physical confinement is proposed by integrating the growth of perovskite QDs with the fabrication process of hydrophobic silica-aerogel powders (SAPs). As a result, the as-synthesized mono- and mixed-cesium-lead-halide QDs @ SAPs composites show tunable photoluminescence from purple to deep red. Besides, the Pr 3+ ions doped CsPbBr 3 QDs @ SAPs composites exhibit moderate quantum efficiency, excellent stability under UV illumination, water moisture as well as temperature variation. Furthermore, performances of white LED device encapsulated Pr 3+ doped composite with blue GaN chip and commercial red (Sr, Ca)AlSiN 3 :Eu 2+ phosphor are evaluated. This work demonstrates a facile and general strategy for synthesizing high-stable all-inorganic cesium-lead-halide QDs for applications in white LED and display devices.
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