Here, Gd-doped CsPbCl1.5Br1.5 nanocrystals (NCs) in borosilicate glass matrix (B2O3−SiO2−ZnO) were prepared by melting quenching and in-situ crystallization. The optical performance of CsPbCl1.5Br1.5 NCs glasses under different heat-treatment temperatures and the content of Gd3+ were analyzed in detail. After CsPbCl1.5Br1.5 NCs glass is doped with Gd3+ ions, the photoluminescence intensity increases and the synthesized Gd-doped CsPbCl1.5Br1.5 NCs glasses have excellent water stability and thermal cycling performance. In addition, the influence of Gd-doped concentrations and heat-treatment temperatures on the amplified spontaneous emission (ASE) thresholds of CsPbCl1.5Br1.5 NCs glasses was studied, and the Gd-doped CsPbCl1.5Br1.5 NCs glasses achieve controllable ASE thresholds at room temperature. The ASE threshold can be as low as 0.39 mJ/cm2. This work offers a neoteric reference for the research in the application of metal ion-doped perovskite NCs and a new idea for the realization of controllable and low ASE thresholds on perovskite NCs.
Halogen vacancies are regarded to play a vital role in photo-induced phase segregation and the resulting switchable emission colors in the soft mixed-halide perovskites ; however, its control strategy via the balanced Pb 0 defects remains a big challenge. The research reports the regulation of synthesis and photochromic behavior via interfacial Eu 3+ /Eu 2+ -Pb 0 /Pb 2+ redox in composites of porous Ca 0.9 Eu 0.1 MoO 4 and nominal mixed-halide perovskite CsPbCl 1.5 Br 1.5 . The composite takes full advantage of Eu 3+ ions with the concerns of its luminescence and variable valences. It provides an additional emission color besides the halide perovskite, manipulates the Pb 0 defects and the resulting Br-rich domain via interfacial redox reaction in the composites. The more contents of surfaced Eu 3+ caused by substituting the unequivalent Ca 2+ ions and the high volume-to-surface ratio of the porous Ca 0.9 Eu 0.1 MoO 4 guarantees the interfacial access for the Eu 3+ and the halides. The research provides some perspectives on the regulation of ionic valence and photoluminescence of halide perovskites with the use of lanthanide ions. The composites may find potential applications in the anti-counterfeiting field.
Currently, it has been found that white light emitting diode (WLED) lack cyan light, which not only hinders high-color-quality lighting applications but also results in an excess of blue light in WLED. In this work, cyan-emissive CsPbCl 1.5 Br 1.5 quantum dots (QDs) were synthesized in a borosilicate glass matrix using a high-temperature melting method. The findings suggest that the increasing SrO leads to a looser glass network, which in turn intensifies phase separation, promotes the crystallization of QDs and enhances the intensity of cyan PL. Significantly, after a heating-cooling cycle, the cyan-emissive glass sample still retained 97 % of its initial PL, suggesting that the synthesized sample exhibited good thermal stability. Finally, the prepared cyan-emissive QDs glass was incorporated into a WLED, effectively fills the lack of cyan light in 470–500 nm, showed a color rendering index (CRI) of 78 at a correlated color temperature (CCT) of 8300 K. This study provides an effective and convenient approach to enhancing the cyan luminescence performance of QDs, highlighting the significant application potential of cyan-emissive QDs glass in optoelectronic devices.
Cu:CsPbCl x Br 3-x quantum dots (QDs) with different Cu-to-Pb molar ratios were synthesized via a solvent-based thermal synthesis method, and highly stable blue-light PCL@Cu:CsPbCl x Br 3-x composite fibers (CFs) were prepared by electrohydrodynamic (EHD) technology. The photoluminescence (PL) properties of these Cu 2+ -doped Cu:CsPbCl x Br 3-x QDs and the stability of polymer encapsulation were investigated in this study. The results showed that with increasing Cu 2+ concentration, the CsPbCl 1.5 Br 1.5 QDs maintained their initial cubic crystal structure. The doping of Cu 2+ ions effectively eliminated the surface defects of CsPbCl 1.5 Br 1.5 QDs, facilitating excitonic recombination through radiative pathways. The PL quantum yield (PLQY) of Cu:CsPbCl 1.5 Br 1.5 QDs increased to 85%. In addition, The fiber encapsulation method effectively improved the stability of the Cu:CsPbCl 1.5 Br 1.5 QDs, After 3 days in water, the fluorescence intensity still remains at the initial 90%. Based on these results, it is believed that Cu:CsPbCl 1.5 Br 1.5 QDs have promising applications in optoelectronic devices in the future.
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