## 1 Introduction  
All-inorganic cesium lead halide (CsPbX\({}_{3}\), X = Cl\({}^{-}\), Br\({}^{-}\), I\({}^{-}\), or their mixture) perovskite quantum dots (PeQDs) have many applications in light-emitting devices [1, 2, 3, 4], solar cells [5, 6, 7], lasers [8, 9, 10], and photodetectors [11] due to their excellent optoelectronic properties, such as cost effectiveness [12], facile synthesis [13], tunable emissions by particle size and composition [14], high photoluminescence quantum yield (PLQY) [15, 16, 17], and narrow emission linewidth [18]. In particular, the CsPbI\({}_{3}\) PeQDs have been intensively studied as down-conversion emitters in light-emitting diodes (LED) due to their high color purity and wide color gamut [19]. Unfortunately, CsPbI\({}_{3}\) PeQDs are vulnerable to phase transfer from photoactive black (\(\alpha\), \(\beta\), \(\gamma\)) phase [20] into the nonphotoactive \"yellow\" (\(\delta\)) phase [21, 22], reducing their stability and thus limiting their practical application [23, 24]. In principle, the instability is chiefly due to the fact that the commonly used capping ligands, oleylamine (OAm) and oleic acid (OA), are highly dynamic and could be easily detached when exposed to external environments including air, heat, and polar solvents [25, 26]. In order to enhance the stability, considerable research efforts have been made, with various strategies developed such as elemental doping [27, 28] and capping ligand engineering [29, 30, 31]. Specifically, [PERSON] et al. doped smaller-sized Zn\({}^{2+}\) into CsPbI\({}_{3}\) PeQDs to obtain CsPb\({}_{1-x}\)Zn\({}_{x}\)I\({}_{3}\) PeQDs, which exhibits improved storage stability arising from increased lattice formation energy due to lattice contraction by Zn\({}^{2+}\) doping [32]. Through a post-treatment method, [PERSON] et al. used the bidentate ligand 2,2'-iminodibenzo acid to effectively passivate the surface defects on CsPbI\({}_{3}\) PeQDs, which resulted in a highly efficient photoluminescence (PL) and much improved storage stability of 15 d [33]. [PERSON] et al. obtained CsPbI\({}_{3}\) PeQDs with excellent storage of up to 180 d, which was achieved by partially replacing the long-chain OAm and OA by octylamine and octanoic acid owing to their stronger adsorption energy [34]. However, both strategies failed to resolve the instability against heat and polar solvents. An alternative method to improve stability against heat and polar solvents is the coating technique of oxides, such as TiO\({}_{2}\)[35], AlO\({}_{x}\)[36], and SiO\({}_{2}\)[37], on CsPbX\({}_{3}\) PeQDs. Among them, SiO\({}_{2}\) is an ideal choice due to its low cost, strong controllability, and high compatibility [38; 39; 40]. [PERSON] et al. reported the realization of monodispersed, SiO\({}_{2}\)-coated, blue-emission CsPbBr\({}_{3}\) PeQDs through a low-temperature synthesis which used tetramethoxysilane (TMOS) as its silica precursor [41]. Through facile reverse microemulsion, our group employed tetraethoxysilane (TEOS) to produce ultrathin, core-shell structured, SiO\({}_{2}\)-coated, Mn\({}^{2+}\)-doped CsPbBr\({}_{3}\) PeQDs in order to improve their heat and water stability [42]. (3-aminopropyl)-triethoxysilane (APTTES) was also used in a synthesis of SiO\({}_{2}\)-coated CsPbBr\({}_{3}\) PeQDs to improve heat and ethanol stability [43]. Most of the coating technology focused on CsPbBr\({}_{3}\) PeQDs, and only mere publications of SiO\({}_{2}\) coating were extended to CsPbI\({}_{3}\) PeQDs due to the fact that the latter is more prone to instability against heat and polar solvents than the former. [PERSON] et al. combined the high-temperature sintering method and atomic layer deposition technique to produce SiO\({}_{2}\)/AlO\({}_{x}\)-coated CsPbI\({}_{3}\) PeQDs with increased stability against heat and polar solvents [44]. [PERSON] et al. synthesized a micro-sized SiO\({}_{2}\) matrix to wrap both CsPbI\({}_{3}\) PeQDs and other emitters using APTES with enhanced storage stability in air [45].