Abstract
Using mesoporous SiO2 to encapsulate CsPbBr3 nanocrystals is one of the best strategies to exploit such materials in devices. However, the CsPbBr3/SiO2 composites produced so far do not exhibit strong photoluminescence emission and, simultaneously, high stability against heat and water. We demonstrate a molten-salts-based approach delivering CsPbBr3/mesoporous-SiO2 composites with high PLQY (89 ± 10%) and high stability against heat, water, and aqua regia. The molten salts enable the formation of perovskite nanocrystals and other inorganic salts (KNO3–NaNO3–KBr) inside silica and the sealing of SiO2 pores at temperatures as low as 350 °C, representing an important technological advancement (analogous sealing was observed only above 700 °C in previous reports). Our CsPbBr3/mesoporous-SiO2 composites are attractive for different applications: as a proof-of-concept, we prepared a white-light emitting diode exhibiting a correlated color temperature of 7692K. Our composites are also stable after immersion in saline water at high temperatures (a typical underground environment of oil wells), therefore holding promise as oil tracers.
Highlights
Using mesoporous SiO2 to encapsulate CsPbBr3 nanocrystals is one of the best strategies to exploit such materials in devices
Emission), making them promising candidates for different optoelectronic applications such as light emitting diodes (LEDs), displays, radiation detectors, and solar concentrators.[1−8] the effective implementation of these NCs in industrial manufacturing processes is limited by their poor stability, which leads to their degradation when they are exposed to humidity, high temperature, and photoirradiation.[9−12]
Letter it hydrophilic or hydrophobic); and (iv) the size of the pores can be finely tuned.[33−37] To date, m-SiO2 has been successfully employed as a matrix to grow lead halide perovskites (LHPs) NCs in its pores, following various approaches.[22−28] The composites obtained at low temperatures
Summary
Letter mixture is of paramount importance in regulating the properties of the final composites. Letter physical properties, our composites were found to be promising as green emitting phosphors in LEDs: the resulting device emitted white light with CIE color coordinates of (0.2985, 0.3076), CCT of 7692 K and exhibited a highly stable PL emission (in terms of peak position and intensity) after 240 h of operation. Experimental Section, characterization of m-SiO2, DLS measurements, PL curves after the aqua regia treatment, composites synthesized by varying the KNO3:NaNO3:KBr molar ratio, tests of films employed for 10 days in remote configuration with a blue LED chip, test of composites exposed to brine, preparation of CsPb(Cl,Br)[3] and CsPb(Br,I)[3] based composites (PDF)
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