Here, we present that the shape and optical properties of CsPbBr3 nanocrystals (NCs) could be tuned by addition of various hydrohalic acids (HX, X = Cl, Br, I). The addition of hydrochloric acid (HCl) and hydrobromic acid (HBr) turns the nanocrystals from nanocubes (NCUs) to quantum dots (QDs). The optical properties are regulated by the composition and quantum confinement effect, while the hydrobromic acid (HBr) addition results in nanosheets (NSs), without a photoluminescence (PL) peak shift. Based on various characteristics, we speculate that the addition of HX leads to protonation of oleylamine from oleylamine into oleylammonium cations that compete with Cs+ during crystallization. The oleylammonium cations at the growing surface of NCs block further growth in the favored direction. Our study provides a facile strategy for tuning and manipulating the shape, size, and optical properties of all-inorganic CsPbX3 NCs and aids in the further exploration of the growth mechanism of perovskite NCs.
Yajuan Wang,Jianing Wang,Lei Wang,Shuonan Wang,Wenyan Liu
All inorganic CsPbBr3 nanocrystals (NCs) have gained significant attention due to their potential as light-emitting diodes, solar cells and other optoelectronic devices. However, to a certain extent, the stability issues of CsPbBr3 NCs under water, light, and thermal conditions limit their further applications. In order to improve stability, this article proposes a strategy of modifying CsPbBr3 NCs with poly(ethylene adipate) (PEA). The surface passivation of macromolecular polymer PEA not only increases the distance between NCs which inhibits the aggregation of small NCs, but also provides a dense protective layer to protect NCs from corrosion by water, air and light. Therefore, the performance of PEA-modified CsPbBr3 NCs in terms of optical properties and stability is significantly improved. The photoluminescence intensity of PEA-modified CsPbBr3 NCs remains at about 40% of the initial intensity when heated to 100 °C, while that of pure CsPbBr3 NCs has decreased to less than 10%. The photoluminescence intensity of PEA-modified CsPbBr3 NCs decreased to 83% of the initial intensity after 7 cycles of heating to 100 °C and then cooling to room temperature, while that of pure CsPbBr3 NCs decreased to 13%. Meanwhile, the PL intensity of PEA-modified CsPbBr3 NCs remained at 66% of the initial intensity after 10 h under 365 nm ultraviolet light, and there is no obvious red shift in PL spectra, while the PL intensity of pure CsPbBr3 NCs only maintained 21% of the initial intensity, accompanied by obvious red shift in PL spectra. The results show that the PEA-modified CsPbBr3 NCs have a positive effect on stability.
Xin Li,Jian Zhang,Jie Liu,Feng Zhang,Siyuan Luo,Huaiqiang Ba,Yu Zhang,Xuhui Xu,Zhichao Liu
Due to the sensitivity to water, the all-inorganic CsPbBr 3 nanocrystals have been widely applied in information encryption with spatial dimensions. However, the absence of time-dimension information limits the information capacity for the application of CsPbBr 3 . In this work, the CsPbBr 3 nanocrystal was combined with water-sensitive borophosphate glass, achieving decomposing/recrystallization of CsPbBr 3 nanocrystal with multi-dimension. The addition of SiO 2 confirms that the collapse of the borophosphate glass network structure causes the exposure of the CsPbBr 3 nanocrystals. The decomposition and recrystallization mechanism of CsPbBr 3 nanocrystals in glass-ceramics upon encountering water has been verified. Finally, an information encryption strategy, using the mixture of CsPbBr 3 glass ceramic and sodium carboxymethylcellulose as ink, is designed via adopting screen-printing technology, which not only provides a new idea for the preparation of CsPbBr 3 nanocrystals, but also establish a new avenue for the information encryption technology.
危险品化学品经营许可证（带存储）