NondemandingIn SituEncapsulation Route to Ultrastable Perovskite Nanocrystals for White Light-Emitting Diodes

Abstract

Although tremendous advancement regarding the highly stable metal halide perovskite nanocrystals (PNCs) has been achieved, previous studies were primarily focused on green light-emitting PNCs (i.e., bromine-based PNCs). The stability of chlorine-based PNCs with a violet or blue emission property was still lagging behind that of their bromine-based counterparts. Herein, a nondemanding and versatile strategy for in situ encapsulating allinorganic chlorine-based PNCs with multifold exceptionally high stabilities was presented. Wellordered mesoporous silica enabled the confined growth of PNCs in its pores followed by the porosity sealing by tetramethyl orthosilicate hydrolysis, thereby rendering full encapsulation of chlorine-based PNCs in dense silica that originated from high-temperature calcination. This judiciously designed structure imparted enclosed violet/blue emitting PNCs impart with outstanding long-term stability (>1.5 year) with high photoluminescence quantum yield (i.e., 30.4%) in pure water as the result of complete isolation of PNCs from detrimental stimuli, eventually leading to the application in the white light-emitting diode device.

Illuminating the Nanoparticle Array: Unveiling the Interplay between Photodegradation and Aggregation Degree of CsPbBr3 Nanocrystals

“…The surface defects, especially the halide vacancies, were the primary reason for photodegradation of the perovskite NCs, which facilitated the hydration reactions. 22,44,45 From the perspective of the bond strength, the chemical bond formed by Pb−I is comparatively weaker than that of Pb−Br, resulting in intrinsic instability in CsPbI 3 . Here, CsPbBr 0.9 I 2.1 and CsPbBr 3 NC arrays (TEM image shown in Figure S6) were assembled together on one substrate to compare their photostability simultaneously.…”

CsPbX3 (X = Cl, Br, and I) Nanocrystals in Substrates toward Stable Photoluminescence: Nanoarchitectonics, Properties, and Applications

“…For example, Wang and co-workers reported ordered mesoporous silica-supported confined chlorine-based metal halide perovskite nanocrystal (PNC) growth in the pores of the matrix materials with porosity sealing utilizing tetramethyl orthosilicate hydrolysis processes. A full encapsulation of chlorine-based nanocrystals was achieved by conducting high-temperature calcination treatment on the precursors, forming violet/blue-emitting composites with long-term stability of greater than 1.5 years as well as a high PL quantum yield of about 30.4% …”

“…A detailed synthetic procedure proposed by Wang et al for the construction of the CsPbX 3 NC encapsulated PNC (CsPbX 3 NCs@mSiO 2 ) composites is shown in Figure a . In this case, the mesoporous silica matrix with a relatively large surface area and outstanding absorbing ability worked as a nanoreactor to attain control of the growth of CsPbX 3 NCs in the matrix pores.…”

“…A full encapsulation of chlorine-based nanocrystals was achieved by conducting high-temperature calcination treatment on the precursors, forming violet/blue-emitting composites with long-term stability of greater than 1.5 years as well as a high PL quantum yield of about 30.4%. 111 A detailed synthetic procedure proposed by Wang et al for the construction of the CsPbX 3 NC encapsulated PNC (CsPbX 3 NCs@mSiO 2 ) composites is shown in Figure 10a. 111 In this case, the mesoporous silica matrix with a relatively large surface area and outstanding absorbing ability worked as a nanoreactor to attain control of the growth of CsPbX 3 NCs in the matrix pores.…”

“…111 A detailed synthetic procedure proposed by Wang et al for the construction of the CsPbX 3 NC encapsulated PNC (CsPbX 3 NCs@mSiO 2 ) composites is shown in Figure 10a. 111 In this case, the mesoporous silica matrix with a relatively large surface area and outstanding absorbing ability worked as a nanoreactor to attain control of the growth of CsPbX 3 NCs in the matrix pores. The calcination solid-state reaction process (at 600 °C) utilized for the encapsulation of CsPbX 3 with SiO 2 was one of the keys in achieving the stability enhancement of the composite system.…”