Weiwei Chen,Xiaosheng Tang,Zhigang Zang,Yue Shi,Zhaoqi Yang,Juan Du
Doping of Mn2+ into semiconductor nanocrystals has been demonstrated to endow them with novel electronic, optical and magnetic functionalities. In this paper, Mn-doped CsPbX3 (X = Br, Cl) quantum dots (QDs) were synthesized at room temperature via a facile strategy by introducing dimethyl sulfoxide (DMSO)-MnBr2/PbX2 composite as a precursor. The excitonic emission spectra of the as-obtained Mn-doped CsPbX3 QDs can be tuned from 517 nm to 418 nm by adjusting the ratio of PbBr2/PbCl2 precisely, and the luminescence mechanism of the doped QDs is discussed in detail. Moreover, the highest photoluminescence quantum yield of the Mn2+ emission achieves 36.7%, which is comparable with QDs prepared by the conventional hot-injection method. Depending on the ratios of PbPb2/PbCl2, the energy transfer rate from the band-edge to Mn2+ excited state is in the range of 0.006–20.42 × 107 s−1. Furthermore, white light-emitting diodes (LEDs) were successfully fabricated by combining the as-prepared Mn-doped CsPbX3 QDs with commercial UV GaN chips, and the high luminous efficiency of the as-prepared white LEDs was developed to 55.9 lm W−1. This work strongly supports the fact that Mn-doped CsPbX3 QDs are promising materials for application in lighting and displaying fields.
Wenli Song,Bing Zhang,Wenli Zhou,Jilin Zhang,Liping Yu,Shixun Lian
All-inorganic perovskite quantum dots (PQDs, CsPbX3, X = Cl, Br, and I) show outstanding application prospects in the field of photoelectric devices. In recent years, the development of PQDs has greatly improved their stability to water, oxygen, and light. However, thermal quenching of PQDs greatly limits their practical application. Herein, we embed PQDs into ATiO3 (A = Ca, Ba, and Sr) of three different mesoporous spherical structures to explore the effect on thermal quenching of PQDs. Because of the unique mesoporous hollow microsphere structure and low thermal conductivity of SrTiO3, it can effectively block the heat transfer and improve the thermal quenching of PQDs. The photoluminescence (PL) intensity of CsPbBr3@SrTiO3 composites is 72.6% of the initial intensity after heating to 120 °C. Moreover, the PL intensity of CsPbBr3@SrTiO3 composites remains about 80% of the initial value even when stored in air for 20 days or irradiated by 365 nm UV light for 48 h. A neutral white light-emitting diode is assembled by a blue chip, CsPbBr3@SrTiO3 composites, and red phosphor of K2SiF6:Mn4+, which has a color temperature of 5389 K and a color gamut covered 133% of National Television Standards Committee (NTSC).
CsPbX 3 (X = Br, I) quantum dots (QDs) have gradually become the star materials in light-emitting diodes (LED), but its stability has a big impact on development. Here, a variety of novel CsPbX 3 -TS-1 nanocomposites have been fabricated and the luminescence wavelength can be tunable by varying the halide nanocomposites (Br, I). What's particularly nice is that the original photoluminescence quantum yield (PLQY) of CsPbBr 1 l 2 QDs approaches 82% and it still has close to 74% after being combined with TS-1. Besides, the nanocomposites enhance stability resisting moisture, thermal stressing and light. In addition, a 460 nm InGaN blue chip, YAG:Ce 3+ and CsPbBr 1 I 2 -TS-1 were equipped with white light emitting diodes (WLEDs), with a luminous effect of 95 lm/W, a color rendering index of 80, and a color temperature of 5144 K. Meanwhile, wide color gamut (116% of the National Television Standards Committee, 86.3% of the ITU-R Recommendation BT. 2020) and great chromaticity coordinate (0.3425, 0.3408) are realized. This is a very important step to open up the awkward situation of the practical application of perovskite QDs materials in LED.
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