synthesis has emerged as the strategy for generating high-quality nanosized particles. [1,2] The resulting composite materials, in particular those inorganic nanoparticles embedded in the nanoporous matrix, often exhibit unanticipated optical, thermoelectric, magnetic, catalytic, and other properties. [1][2][3][4][5] The chemistry inside a nano-confined space would impose the physical constraints and chemical effect to increase reaction rates, limit growth size and stabilize reactive species. [5] Controlling the size and shape of semiconductor nanocrystals will enable tuning the bandgap of semiconductors via the quantum size effect, thus launching an effective route to precisely control the emission wavelength of nanocrystals. In addition, the nano-sized cage would also isolate and stabilize the formed nanocrystals. [6] Metal halide perovskite quantum dots (QDs) recently have attracted considerable attention due to their outstanding optical and electric properties, which make them promising candidates as building blocks of optoelectronic devices, including light-emitting diodes (LEDs), [7] photovoltaics, [8,9] lasers, [10,11] and photodetectors. [12] Recent intriguing concepts have elegantly used nano porous matrices to integrate with perovskite materials including nanocrystals and films. Such systems exhibit efficient manufacturing processes with much-improved material stability [13,14] and high photoluminescence quantum yield (PLQY) above 50%. [15][16][17] One facile strategy to create such systems is in situ nano-confined growth of metal perovskite QDs in a nanoporous template. However, prior studies have focused on using powders or thin films, [16][17][18][19] the low-dimensional morphologies of which usually suffer from inherent problems such as poor handling properties, high transparency limitations, and mechanical instability towards optical applications. For the integration of perovskite QDs composites into optoelectronic devices, a complex and time-consuming multi-step package procedure is required. [18,20] Thus, optically transparent, robust, and monolithic nanoporous templates are therefore highly sought after.The concept of optics and glasses go hand in hand. Recently inorganic glasses have drawn increasing attention as perovskite QDs matrix owing to their superior optical quality and thermal resistance. [21][22][23] The inorganic glass networks could act as a Prior nano-confined matrices for perovskite quantum dots (QDs) dealt only with powders or thin films, which usually suffer from poor handling properties and high transparency limitations for integrating into optical devices. Here, the nano-confined growth of perovskite QDs in an optically transparent, robust, and monolithic matrix by using nanoporous glass (NG) as a nano-reactor is demonstrated. Owing to quantum confinement effects in the inherent nanoporous network, rapid nanoconfined low-temperature solutionprocessed perovskite QDs could synthesize spontaneously. The binding energy of CsPbBr 3 QDs in NG has been enhanced to ≈177.2 meV due to t...
