Fig. 1. Classification of luminescent ions-doped dual-phase nano-glasses and their potential applications

Fig. 2. Schematics of in situ and ex situ approaches of making optically active nanoparticles （OANPs）-in-glass hybrid materials^［32］. （a） The basic in situ method consists of preparing a precursor glass with appropriate compositions by melt-quenching methods （casting） followed by a controlled crystallization process via thermal treatment； （b） the basic ex situ method is executed as follows： the precursor glass is pulverized into fine glass powder， which is mixed and homogenized with pre-fabricated NCs； the mixture is heated at temperatures above the softening point of the glass matrix but below the decomposition temperature of the NCs； after a brief heating period， the molten （viscous） mixture is cast into a mold forming the GCs

Fig. 3. Schematic of typical phase separation of multi-component precursor fluorosilicate glass （SiO₂-ZnF₂-KF）^［31］. （a） Droplet phase separation；（b） interpenetrating phase separation

Fig. 4. Schematic showing the possibilities of tailoring the energy-transfer rate （W_ET） by either varying the inter-ionic distance （R） between a donor （D） and an acceptor （A） or by modifying spectral overlap ∫gDgAdE between the emission （D_em） and absorption （A_ex） spectra of the donor and the acceptor， respectively^［23］. Left column： efficient ET only occurs when R is smaller than a critical distance of interaction R_C. The variations in R are achieved by using （a） nanocrystals （NCs） with a core-shell structure^{and （b） by selectively doping into a dual-phase glass ceramic （GC） containing two different types of NCs. Right column： modifications of the spectral overlap by （c） the electric-field-induced quantum-confined Stark effect and （d） by ligand-field engineering}

Fig. 5. Transmission electron microscopy （TEM） test of dual-phase Ga₂O₃/YF₃ NPs in a nanostructured-glass-ceramics^［23］. （a） Dark-field TEM and （b） HAADF-STEM images； STEM-EDS mapping of （c） Y³⁺， （d） F^-， （e） Er³⁺， （f） O^2-， （g） Si⁴⁺， （h） Ga³⁺，and （i） Ni²⁺ ions from the area shown in Fig. 5（b），and the doping concentrations （in mole fraction） of Ni²⁺ and Er³⁺ are 0.5% and 1.0%，respectively；（j） averaged STEM-EDS analysis taken from three different regions of Fig. 5（a）

Fig. 6. The spectra of 0.15%Ni²⁺/1.0%Yb³⁺/0.2%Er³⁺/0.2%Tm³⁺（in mole fraction） co-doped PG and GC samples excited by a 980 nm laser diode^［24］. （a） NIR emission spectra；（b） upconversion emission spectra

Fig. 7. Broadening of Ni²⁺ fluorescence bandwidth in nanostructured-glass-ceramics containing dual-phase ZnGa₂O₄/ZnF₂ NPs^［25］. （a） Comparison of the normalized Ni²⁺ emission spectra of the ZnGa₂O₄^［37］， ZnF₂^［38］， and KZnF₃^［38］ single-phase GCs with the newly developed dual-phase GC； （b） HAADF-STEM image of the GC sample； （c） PL emission spectra of the 0.5% Ni²⁺-doped PG and ZnGa₂O₄/ZnF₂ dual-phase GC sample excited by an 808 nm laser diode； （d） Ni²⁺： 1350 nm/1560 nm decay spectra of 0.5% Ni²⁺-doped ZnGa₂O₄/ZnF₂ dual-phase GC sample excited by an 808 nm laser diode^［25］

Fig. 8. Regulating Ni²⁺ local photon states density in nanostructured-glass-ceramics containing dual-phase Au/γ-Ga₂O₃ NPs^［28］. （a） Transmission spectra of the 0.15% Ni²⁺ singly-doped and 0.15% Ni²⁺∕0.5% Au-codoped PG and GC samples （the thickness is 1.2 mm）， the inset shows the digital photographs of the samples； （b） emission spectra of the samples doped with 0% Au （Ni GC）， 0.3% Au （0.3AuNi GC）， 0.5% Au （0.5AuNi GC）， and 0.7% Au （0.7AuNi GC） excited at 980 nm laser diode； （c） simulation model as referred to the TEM image shown in Fig. 8（d）； （d） normalized local electric field （E_loc） distribution with respect to the incident 980 nm pump light （E₀） in the single-phase Ga₂O₃ （lower right） and dual-phase Ga₂O₃ and Au GCs （upper right）

Fig. 9. Emission spectra of CsPbBr₃ QD glass with different Ag₂O concentration excited by a 400 nm light source^［30］

Fig. 10. Optical temperature measurement experiment of Yb³⁺/Er³⁺/Cr³⁺ co-doped nanostructured-glass-ceramics containing dual-phase Ga₂O₃/YF₃ NPs^［17］. （a） Sketch showing the distribution and dual-modal luminescent behaviors of Yb³⁺/Er³⁺ and Cr³⁺ ions in the dual-phase GC； （b） UC emission spectra of the Yb³⁺/Er³⁺/Cr³⁺ triply doped GC—a sample in the wavelength range 500‒570 nm at different temperatures （303‒563 K）， the insets show normalized spectra （top） and UC luminescent photograph （bottom）； （c） impact of temperature （303‒563 K） on Cr³⁺ PL spectra in the Yb³⁺/Er³⁺/Cr³⁺ triply doped GC， the insets are normalized emission spectra （top） and luminescent photograph （bottom）； （d） Cr³⁺ decay curves versus temperature

Fig. 11. Optical temperature measurement experiment in nanostructured-glass-ceramics containing dual-phase Tm∶NaYbF₄ and CsPbBr₃ NPs^［27］. （a） Temperature-sensitive UC emission spectra for the dual-phase glass under 980 nm laser excitation； （b） temperature-dependent integrated UC intensity of exciton recombination and Tm³⁺ UC emissions at 477 nm （¹G₄→³H₆）， 650 nm （¹G₄→³F₄）， and 707 nm （²F_2，3→³H₆）； （c） real-time temperature-measuring system to determine the actual temperature of an object coated with the dual-phase glass. UC emission spectra are directly read out from the emitting region via a spectroradiometer to obtain FIR values. The temperature is precisely controlled through temperature-controlling stage， and the pumping source is a common 980 nm NIR laser