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The formation mechanism of Cd–S–Se quantum dots (QDs) with a CdS/CdSe core–shell structure within a silicate glass system was investigated by monitoring the change in the first excitonic absorption peak of CdSe, CdS, and Cd–S–Se QDs as a function of the heat‐treatment (HT) duration. When a silicate glass containing QD formation components for CdSe or CdS single‐phased QDs was heat‐treated, CdSe QDs grew via Ostwald ripening, whereas CdS QDs hardly formed within the given silicate glass matrix. When the glass, including CdO, ZnSe, and ZnS, was utilized for the synthesis of Cd–S–Se QDs within the glass matrix, Cd–S–Se QDs were successfully formed and exhibited similar growth behavior to CdSe QDs during the initial stage of HT. The structural changes in the QD‐embedded glasses during HT were also monitored by Raman spectroscopy and discussed, and a possible formation mechanism of CdSe/CdS core–shell‐structured QDs within silicate glasses is suggested. [ABSTRACT FROM AUTHOR]

• Adjusting optical performance of PbS QDs embedded glass to cover the whole telecommunication bands. • Revealing the absorption cross sections of PbS QDs at 1040 nm are 4–13 × 10−16 cm2, the bi- and tri-excitons lifetime is ∼60 and ∼10 ps. • Obtaining the broadband net gain in 1500–1620 nm in single PbS QDs embedded glass with a threshold of < N >=4.1. • Achieving a maximum gain time of ∼20 ps and gain coefficient of >120 cm−1 for PbS QDs embedded glass. Lead sulfide quantum dots (PbS QDs) have a unique performance in the near-infrared (NIR) range. In-situ precipitation of PbS QDs in glass not only improves the stability, but also is easy to be fabricated fiber compatible with silicon photonics. In this work, we reveal that absorption cross sections of PbS QDs at 1040 nm are 4–13 × 10−16 cm2, the bi- and tri-excitons lifetime are∼60 and ∼10 ps due to the trap-assisted Auger recombination using transient absorption (TA). Furthermore, we demonstrate the broadband net gain in 1500–1600 nm in single PbS QDs embedded glass with a gain threshold of < N >= 4.1 (averaged number of excitons), and achieve the maximum gain time of ∼20 ps and gain coefficient of >120 cm−1. These results illustrate the existing obstacles to achieve the net gain in PbS QDs embedded glass, which is important for applications on fiber amplifiers, NIR laser and high-capacity telecommunication. [ABSTRACT FROM AUTHOR]

CsPbBr3−xIx quantum dots were precipitated in boro‐germanate glasses with various Br/I ratios by the melt‐quenching method. When the heat treatment temperature (TH) increased from 480 to 550°C, more I− entered the perovskite crystal lattice, resulting in lattice expansion, the X‐ray diffraction peaks of CsPbBr1.5I1.5 glasses shifted to small angles. The high concentration of I− entered into the perovskite crystal lattice, decreasing the bandgap. The photoluminescence (PL) peaks of CsPbBr1.5I1.5 glasses redshifted from 577 to 620 nm, the PL peaks of CsPbBrI2 glasses shifted from 614 to 636 nm, and the PL peaks of CsPbBr0.5I2.5 glasses shifted from 650 to 672 nm. As the ratio of Br/I reduced from 2.5/0.5 to 0.5/2.5, the PL lifetime of CsPbBr3−xIx glass increased from 2.08 to 74.5 ns. With the delay time from 1 to 1500 ps, the carriers gradually accumulated in the band‐edge state, and the bleaching signal intensity increased. Then more and more carriers returned to the ground state through radiative or nonradiative recombination, the bleaching signal intensity decreased. [ABSTRACT FROM AUTHOR]

Embedding CdTe QDs into glass can improve the thermal and chemical stability of QDs, which facilitates their wide and endurable applications. However, the small tunable spectral range of photoluminescence, low quantum efficiency, and large full width at half maximum limit their wide applications. In this work, effect of introduction of CaO into glass matrix on the formation and optical properties of CdTe QDs is investigated. High concentration of CaO in glasses increases the solubility of Te in glasses, and consequently hinders the precipitation of CdTe QDs in glasses. By adjusting the heat-treatment temperature, average diameters of CdTe QDs are tuned in the range of 2.5–9.0 nm and their photoluminescence bands are tuned from 550 to 800 nm. More importantly, the absolute photoluminescence quantum yield is boosted up to 41.9 %. Results reported in this work indicate that CdTe quantum dots embedded in glasses are promising for applications in light-emitting devices. • High CaO concentration promote the dissolution of Te in the glass. • Photoluminescence of CdTe QDs doped glass is tuned from 550 nm to 800 nm. • PLQY of CdTe QDs doped glasses reaches 41.9 %. [ABSTRACT FROM AUTHOR]

Lead chalcogenide quantum dots have particular optoelectronic properties induced by the quantum confinement effects and have promising potentials towards applications in infrared spectral range. Modulation of the optoelectronic properties of lead chalcogenide quantum dots is mainly based on the thermal treatment. In this work, precipitation and optical properties of alloyed PbSe x S 1-x quantum dots in glasses are investigated. Composition, size, absorption, and photoluminescence properties of PbSe x S 1-x quantum dots are modulated by chalcogen elements in glasses and thermal treatment. By adjusting the concentration of ZnSe and ZnS in the glasses, average diameters of the PbSe x S 1-x quantum dots are tuned in the range of 8.1–16.1 nm, their absorption peak wavelengths are tuned in the range of 724–2497 nm, and photoluminescence bands are tuned in the range of 1016–2165 nm with full width at half maximum in the range of 167–517 nm. Fraction of Se in the PbSe x S 1-x quantum dots precipitated in glasses is dependent on the concentrations of ZnSe and ZnS in the glass and heat-treatment temperature. Increase in concentration of S in the glasses results in the reduction of relative fraction of Se in the PbSe x S 1-x quantum dots formed in glasses. More importantly, high heat-treatment temperature promotes the enrichment of Se in PbSe x S 1-x quantum dots, and Se fraction in PbSe x S 1-x quantum dots increases from 0.69 to 0.89, from 0.53 to 0.85, from 0.47 to 0.79, and from 0.45 to 0.76 for those precipitated in glasses with ZnSe/(ZnSe+ZnS) molar ratios of 0.545, 0.375, 0.286, and 0.231, respectively. Increase in ZnSe/(ZnSe+ZnS) molar ratios in glasses also leads to reduction in diameter of PbSe x S 1-x quantum dots formed in glasses. These alloyed PbSe x S 1-x quantum dots also exhibit improved photoluminescence quantum yields and enhanced resistance to thermal quenching of photoluminescence. [Display omitted] [ABSTRACT FROM AUTHOR]

PbS quantum dots (QDs) embedded glasses have been investigated for decades, but their applications are limited to the color filters and saturable absorbers for laser pulse generation so far, mainly due to the low photoluminescence quantum yield (PL QY) induced by the surface defects. Here, by increasing the sulfur to lead molar ratio in the glasses, surface defects of PbS QDs can be partially passivated and the fast trapping of charge carriers is reduced. As a result, PL QY of PbS QDs embedded glasses increases with larger sulfur to lead molar ratio, and PL QY as high as 46.9% is achieved. The improved PL QY along with good thermal and photo-stability makes the PbS QDs embedded glasses promising for near-infrared light generation. By integrating the PbS QDs embedded glass slab with light emitting diode (LED) chip, NIR LEDs with external quantum efficiency of 4.47% (@ ∼1.4 μm) with full width at half maximum larger than 140 nm are realized. Using this approach, it is also versatile to fabricate high-performance and broadband NIR LEDs with PbS QDs embedded glasses as light converters. [Display omitted] • Large molar ratio between S and Pb is beneficial to passivate the surface defects of PbS QDs in glasses. • Photoluminescence quantum efficiency as high as 46.9% was realized for PbS QDs embedded glasses. • Passivation of surface defects of PbS QDs in glasses improved their resistance to temperature and light irradiation. • EQE of near-infrared LED based on PbS QDs in glass as high as 4.47% was achieved. [ABSTRACT FROM AUTHOR]

• Highly luminescent CsPbBr3 PQDs are successfully embedded in a stable tellurite glass host. The influence of structural changes on PL properties is studied. • The enhancement mechanisms related to the Ag doping and structural changes are revealed. • The PLQYs of CsPbBr3 are significantly enhanced to 33.9% in tellurite glasses. Highly luminescent CsPbBr 3 perovskite quantum dots (PQDs)-doped tellurite glasses are prepared by the cost-effective and reproducible melt-quenching and thermal heating method. The photoluminescence quantum yields (PLQYs) are significantly enhanced to 33.9% by glass structural modification and Ag doping. The enhancement mechanisms especially that related to the Ag doping are comprehensively discussed according to high-resolution transmission electron microscope analysis and the first-principles calculation for the first-time. The glass structure dependences of PL emissions are studied as a function of temperature from 78 K to 318 K. Based on the optimized glass sample, robust temperature-, irradiation- and high-current-resistant (up to the highest level of 300 mA yet reported) white light-emitting diode module is realized with an external quantum yield of 20%, a luminous efficiency of 65 lm/W, a correlated color temperature of 4063 K and a good color stability. [ABSTRACT FROM AUTHOR]