RESUMEN
Metal halide perovskite quantum dots (QDs) have excellent optoelectronic properties; however, their poor stability under water or thermal conditions remains an obstacle to commercialization. Here, we used a carboxyl functional group (-COOH) to enhance the ability of a covalent organic framework (COF) to adsorb lead ions and grow CH3NH3PbBr3(MAPbBr3) QDsin situinto a mesoporous carboxyl-functionalized COF to construct MAPbBr3QDs@COF core-shell-like composites to improve the stability of perovskites. Owing to the protection of the COF, the as-prepared composites exhibited enhanced water stability, and the characteristic fluorescence was maintained for more than 15 d. These MAPbBr3QDs@COF composites can be used to fabricate white light-emitting diodes with a color comparable to natural white emission. This work demonstrates the importance of functional groups for thein situgrowth of perovskite QDs, and coating with a porous structure is an effective way to improve the stability of metal halide perovskites.
RESUMEN
The major histocompatibility complex (MHC) is a gene cluster directly related to immune response. The highly polymorphic nature of the MHC class I genes corresponds to variations of the pathogens and are crucial for individual survival during infection. During primate evolution, the diverse forms of MHC class I genes came to existence due to different time of divergence and survival pressure. Over time, this led to changes in the number as well as the function of these genes, and even the emergence of species-specific genes. In this paper we describe the overall features of primate MHC class I genes, with an emphasis on the characteristics of six classical MHC class I genes in the typical primate species and their interrelationships.