Quantum Dots Glass Research Articles

Dual-phase Cs4PbBr6/CsPbBr3 perovskite quantum dot borosilicate glass for WLED applications

Owing to inherent structural instability of perovskite quantum dots, they are instability in humid environments and high temperatures conditions. To address this issue, a simple, environmentally friendly glass encapsulated technology is used to protect the perovskite quantum dots. Meanwhile, the dual-phase perovskite structure realized by phase transition engineering can further increase the stability of perovskite quantum dots. In this study, 3D CsPbBr3/0D Cs4PbBr6 dual-phase coexisting perovskite quantum dot glass powders were synthesized through melt quenching and subsequent crystallization induction of thermal treatment and water molecule, respectively. Results showed that compared with thermal treatment induction, perovskite QDs glass powders by water molecules induction exhibited a high PLQY of 24.7 % with a central wavelength of 519 nm and displayed excellent environmental stability. By combining green fluorescence from 3D CsPbBr3/0D Cs4PbBr6 QDs glass powders and red fluorescence powders (CaAlSiN3:Eu), a WLED device with an impressive EQE of 20.6 % was created, indicating a promising application potential.

Highly efficient red emission of CsPbBrI2 quantum dots glasses modified by Nb5+ for light-emitting application

Red-emitting perovskite quantum dots (QDs) have significant potential for application in optoelectronic devices. However, their application is hindered by preparation challenges and low photoluminescence quantum yield (PLQY). In this study, CsPbBrI2 red-emitting QDs with a PLQY of up to 58.73 % were synthesized in germanium borate glass. The experimental results indicated that the addition of Nb5+ can not only partially replace the Pb2+ sites but also passivate halogen defects in QDs, enhance radiative transitions, and significantly improve the lattice ordering of CsPbBrI2 QDs glass. Additionally, the incorporation of Nb2O5 supplies free oxygen, facilitating the conversion of [BO4] to [BO3] in the glass network, which results in a looser structure conducive to crystallization. Moreover, the Nb5+-doped CsPbBrI2 QDs glass demonstrated excellent hydrothermal stability. The QDs glass exhibiting the highest luminescent performance was subsequently combined with an InGaN blue chip to create a WLED with a color rendering index (CRI) of 82.7. This study offers an innovative methodology for synthesizing perovskite QDs glass materials with enhanced red emission efficiency through transition metal doping, highlighting their significant potential for practical applications in WLEDs.

Impact of Eu3⁺ on the self-crystallization of CsPbBr1.5Cl1.5 in glass-ceramics for precision temperature sensing applications

All-inorganic perovskite QDs, such as CsPbX3(X = Cl, Br, I), have garnered significant attention in the field of optoelectronics as emerging photonic materials. Rare-earth (RE) doping is an effective strategy for enhancing the optical properties of CsPbX3 perovskite quantum dot glasses. Therefore, investigating the crystallization behavior of rare-earth ion-doped CsPbX3 glass and the energy transfer mechanisms between rare-earth ions and CsPbX3 is crucial for advancing the development of rare-earth-doped perovskite glass materials. The paper systematically introduces the preparation methods, structural characteristics, and applications of CsPbBr1.5Cl1.5 QDs in optoelectronic devices. Firstly, the detailed effects of Eu3+ and F⁻ doping on the structure and optical properties of CsPbBr1.5Cl1.5 quantum dot glass are discussed. Subsequently, the crystal structure, size distribution, and morphology of CsPbBr1.5Cl1.5 QDs are characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Furthermore, the application of CsPbBr1.5Cl1.5 QDs in LEDs and temperature sensing optoelectronic devices is explored, highlighting their performance and potential value in these applications. This study provides important references and guidance for further research and application of CsPbBr1.5Cl1.5 QDs in the field of optoelectronics.

CsPb(Br/Cl)3-Sm3+ codoped glasses for optical temperature sensing in FIR and chromatic coordinate modes

We have fabricated Sm3+ doped glasses, CsPb(Br/Cl)3 quantum dots (QDs) glasses and CsPb(Br/Cl)3-Sm3+ codoped glasses by melt-quenching and subsequent heat treatment for optical temperature sensing. Photoluminescence (PL), photoluminescence excitation (PLE) spectra and PL decay have been measured. Two CsPb(Br/Cl)3-Sm3+ samples with different PL peaks of QDs at 486 nm and 503 nm have been studied for fluorescence intensity ratio (FIR) and chromatic coordinate sensing. The CsPb(Br/Cl)3 QDs and Sm3+ ions exhibit distinguished spectral components and they are dynamically independent. PL intensity of QDs rapidly decreases with temperature, whereas PL intensity of Sm3+ slowly decreases with temperature. PL intensity of Sm3+ ions and CsPb(Cl/Br)3 QDs have been independently fitted. Then, FIR sensing has been studied. The different variation in PL intensity with temperature for Sm3+ and CsPb(Cl/Br)3 leads to the change of luminescent color and chromatic coordinate. The chromatic coordinate sensing has also been studied. Absolute sensitivity (Sa) and relative sensitivity (Sr) have been analyzed for both FIR and chromatic coordinate sensing. Compared with the chromatic coordinate mode, FIR mode has the larger Sa and Sr. But the chromatic coordinate method is more convenient for application, which does not require separating two spectral components. Both FIR and chromatic coordinate sensing modes show outstanding temperature cycling characteristics.

Transparent medium embedded with Mn2+ doped perovskite quantum dots for underwater X-ray imaging

Inorganic cesium lead halide (CsPbX₃, X = Cl, Br, I) quantum dots (QDs) have attracted significant interest owing to their superior optoelectronic properties, which are promising for a wide range of optoelectronic applications including low-threshold optical-pumped lasers, high-efficiency light-emitting diodes, photodetectors, and solar cells. However, the QDs exhibit significant drawbacks in terms of stability, being susceptible to external environmental factors. Herein, Mn2+ doped CsPbClxBr3-x QDs were in-situ formed from a glass matrix, achieving both enhanced stability and tunable luminescence. Due to the excellent optical properties of Mn2+ doped CsPbClxBr3-x QDs and the protection of the glass matrix, the glass exhibits a high resolution of 17.2 lp mm−1 and underwater X-ray imaging capabilities. These attributes render Mn2⁺-doped CsPbClxBr3-x QD glass to be of significant application value in the X-ray imaging field, potentially to provide new material support for the development of optoelectronic technologies.

Enhanced photoluminescence properties and stability of CsPbBr3 quantum dots borosilicate glasses modified by ZnO

Halide perovskite quantum dots (QDs) glass has attracted much attention in the field of optoelectronics, but its photoluminescence (PL) properties and water stability still need further improvement. In this work, the melt-quenching method is used to successfully precipitate CsPbBr3 QDs in borosilicate glass. By increasing the concentration of ZnO, the photoluminescence quantum yield (PLQY) of CsPbBr3 QDs glass is enhanced up to 30 times from 1.91 % to 65.87 %. The results demonstrate that the introduction of ZnO loosens the glass network structure, which contributes to the QDs to precipitate. In addition, it can be found that the PL intensity maintains 91.68 % of the initial PL intensity after 30 days of immersion, which is attributed to ZnO delays the corrosion of borosilicate glass by water. The effect of ZnO-modified borosilicate glass structure on PL and stability provides a certain reference value for further research on QDs glass, and the good PLQY and water stability make ZnO-modified CsPbBr3 QDs glass a potential material in the field of WLEDs.

Preparation of F/Mn-doped CsPb(Br/Cl)3 quantum-dot glass and their luminescence properties

All inorganic lead halide cesium perovskite quantum dots (QDs) have attracted much attention due to their excellent luminescence properties, but further development is restricted by their stability and the existence of toxic element lead. In this paper, F/Mn-doped [Formula: see text] QDs glass was prepared by melt quenching and heat treatment, with reduced Pb content effectively. The result shows that the spectrum of the QD glass is adjustable between 450 nm and 515.4 nm by changing the feeding ratio of Mn-Pb ion and heat treatment temperature. Moreover, the indraught of [Formula: see text] effectively improves the PLQY of [Formula: see text] QDs glass and serves as a red-emitting. The prepared composites not only maintain good fluorescence characteristics, but also greatly improve the stability of QDs. And successfully coupled with blue LED chips to synthesize WLED, Under 20 mA current, the color coordinate is (0.3446, 0.3389).

TiO2 doping promoted nucleation of CsPbX3 (X = Cl, Br, I) quantum dots in glass with improved luminescent performance and stability

Stability hinders further development of all-inorganic CsPbX3 (X = Cl, Br, I) quantum dots (QDs) although they exhibit promising prospects in optoelectronic applications. Coating perovskite quantum dots (PQDs) with a glass network to form QD glass can significantly improve their stability. However, the dense glass network degrades their luminescent performance. In this work, the crystallization behavior of PQDs in glass and better luminescence properties are prompted by introducing titanium dioxide into borosilicate glass. The luminescence intensity of TiO2-doped CsPbBr3 QD glass is increased by 1.6 times and the PLQY is increased from 49.8 % to 79 % compared to the undoped glass. Evidence proves that the improved properties are attributed to the enhanced nucleation effect of titanium dioxide during the annealing process. Benefiting from the densification of the glass network caused by titanium dioxide doping, the stability of the PQD glass is further improved. LED devices with an ultra-wide color gamut that fully covers the NTSC1953 standard and achieves 128.6 % of the NTSC1953 standard as well as 91.1 % of the Rec.2020 standard were fabricated by coupling PQD glass powder, demonstrating promising commercial applications of PQD glass in optoelectronic displays.

Multicolor tunable persistent luminescence mechanism in well-designed inorganic composites.

Herein, by ball milling CsPb(Br/I)3 quantum dot glass powder with Sr2MgSi2O7:Eu2+, Dy3+ phosphor, multicolor tunable long persistent luminescence (LPL) in inorganic composites with more than 700 min attenuation time can be obtained via a radiation photon reabsorption process. Attractively, the wide color gamut of LPL spectra overlaps the National Television System Committee space 74%. Notably, the luminescence intensity remains stable when the inorganic composites are composed with UV light for 100 h. Finally, practical anticounterfeiting application is successfully realized based on the prepared LPL inorganic composites. This work provides a new, to the best of our knowledge, perspective to achieve polychromatic adjustment of LPL.

Se4+ doped CsPbX3 (X=Cl/Br, Br, Br/I, I) perovskite quantum dot glasses for long wavelength pass filters with deep energy level quenching mechanism

CsPbX3 (X = Cl/Br, Br, Br/I, I) perovskite quantum dots (QDs) glasses have enormous application potential in the field of long wavelength pass (short wavelength cutoff) filters. In this work, the CsPbX3 (X = Cl/Br, Br, Br/I, I) QDs doped with Se4+ were prepared in the borogermanate glass matrix. To quench strong exciton emission of QDs, the CsPbX3 (X = Cl/Br, Br, Br/I, I) perovskite QDs glasses were doped with Se4+ at different concentrations of 0, 0.05 %, 0.1 % and 0.2 %, respectively. The nanocrystal structure, transmittance, optical density, photoluminescence (PL), PL excitation and PL decay have been investigated. The working wavelength of filters has been extended to wide range from 440 nm to 650 nm. The samples have large optical density in cutoff region, excellent steepness in the transition region, and high transmittance in transmission region. As Se4+ concentration increases, the PL intensity is quenched and the PL lifetime is decreased obviously for CsPbX3 QDs glasses, whereas the absorption and transmittance characteristics for filters are less affected. The quenching mechanism is attributed to nonradiative recombination by deep energy level traps. The Se4+ doped CsPbX3 QDs glasses can meet requirements for the long wavelength pass filters.

Batch preparation process of composite materials of quantum dot glass and polystyrene used in backlight displays

All-inorganic CsPbX3 quantum dots (X = Cl, Br, or I) are regarded as a new generation of efficient luminescent materials for displays and solid-state lighting due to their excellent optoelectronic properties. However, the poor stability of CsPbX3 quantum dots severely hampers their commercial applications. Currently, the in-situ growth of CsPbX3 quantum dots in amorphous glass has emerged as a crucial approach to significantly enhance their stability. This study successfully synthesized large-scale CsPbBr3@glass materials using a one-step self-crystallization method involving melting, quenching, and heat treatment. CsPbBr3@glass was blended with polystyrene (PS) through melt blending and extrusion, resulting in the fabrication of a CsPbBr3@glass@PS film. By controlling the content of quantum dot glass in polystyrene and adjusting the film's thickness, a green light film with color coordinates (0.1629, 0.7759) and a Full Width Half Maximum (FWHM) of 19.78 nm was achieved. The film produced through this process demonstrated exceptional stability, retaining 90% of its luminous intensity after 1000 h of rigorous aging experiments. Furthermore, when combined with potassium fluorosilicate composite polystyrene film and a blue light chip, a 7-inch LCD display with a color gamut of 135.8% of NTSC 1953 and 92.8% of Rec. 2020 was successfully assembled. This research holds significant reference value for the commercial application of quantum dot glass.

All-inorganic luminescent solar concentrator based on transparent multicomponent glasses embedded with PbSe QDs

Luminescent solar concentrators (LSCs) have become a seminal technology with the possibility of producing carbon–neutral buildings. However, current LSCs developed based on organic or organic–inorganic strategies face limited long-term outdoor stability. Here we developed an inorganic PbSe QDs glass with a strong UV absorption, large Stokes shift, broadband excitation and emission, and high transparency in the visible range. In addition, the suitability of inorganic PbSe quantum dots (QDs) glasses for use in LSCs as both transparent matrix and luminophore, as an alternative to the combination scheme of organic dyes or colloidal QDs and organic polymer materials was explored. Coupled with a commercial silicon solar cell, the as-prepared transparent LSC exhibited an optical efficiency of 10.13 % and a power conversion efficiency of 1.59 % under standard sunlight. These results demonstrate a new strategy to fabricate stable all-inorganic transparent LSCs for building integrated photovoltaic systems.

Energy transfer modulation of photoluminescence in glasses co-doped with Nd3+ and CsPbBr3 quantum dots

Nd3+ co-doped CsPbBr3 perovskite quantum dots (PQDs) glasses were prepared by conventional melt-quenching followed by a thermal treatment process. With the introduction of Nd2O3 to the parent glass, the optical properties of the CsPbBr3 PQDs are significantly improved. The energy transfer from CsPbBr3 PQDs to Nd3+ ions was investigated and confirmed by excitation and emission spectra. The results show that visible excitation band width for the near-infrared (NIR) emission of Nd3+ ions is significantly increased in the presence of PQDs. The strategy for modulation of the optical properties by the energy transfer between rare earth ions and PQDs in the glass matrix could be further utilized for spectral engineering of photonic glasses for optoelectronic applications.

Nd-doped CsPbBr3 borosilicate glass ceramics: Crystallization behavior and photoluminescence kinetics

Rare-earth (RE) doping is one of the valid approaches to optimize the optical performance of the CsPbBr3 perovskite quantum dot glass. Thus, the research on the crystallization behavior of RE ions doped CsPbBr3 borosilicate glass and the energy transformation mechanism between the RE ions and CsPbBr3 is significant for the development of advanced Ln-doped perovskite glass materials. In this work, CsPbBr3 borosilicate glass ceramics doped with different concentrations of Nd2O3 were successfully synthesized. It was found that Nd2O3 makes the glass network structure more compact and then inhibits the precipitation of CsPbBr3 nanocrystals. Additionally, there is energy transfer between Nd3+ and CsPbBr3, which quenches the photoluminescence of CsPbBr3 borosilicate glass. This work deepens the understanding of the structural and photophysical properties of Ln-doped CsPbBr3 borosilicate glass ceramics and provides a reference value for the related work of RE ions doped perovskite borosilicate glass.

Enhanced luminescence and high stability in Gd3+-doped CsPbBr3 perovskite quantum dots glasses for X-ray detection

The highly luminescent CsPbBr3 perovskite quantum dots (PQDs) glass has shown great potential for applications in X-ray radiation. In this study, the synthesis, crystallization behavior, structural photoluminescence (PL), and X-ray excited luminescence (XEL) of new scintillation luminescent ion Gd3+-service behavior studies were conducted to evaluate the effectiveness of the Gd3+-doped PQDs glasses as X-ray scintillators. The direct band gap semiconductor property makes it suitable for successful detection of X-ray radiation and allows for efficient absorption and emission of X-ray photons, leading to enhanced scintillation performance. These findings highlight the potential of Gd3+-doped CsPbBr3 PQDs glasses as promising materials for X-ray scintillation applications.

Color adjustable CsPbX3 (X=Cl, Br, I) perovskite quantum dots germanate glass

CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) have attracted extensive attention due to their great application prospects in the photoelectronic field. However, the poor long-term stability still limits their practical use. In this work, a whole series of CsPbX3 QDs were precipitated in a germanate glass matrix by a melt quenching method. The emission wavelength can be tunable in the entire visible spectral region by adjusting of the halide ions and the thermal treatment process. The photoluminescence quantum yield of CsPbBrxI3-x QDs glass can reach up to 38.24%. The exciton binding energies of CsPbBrxCl3-x, CsPbBr3 and CsPbI3 QDs glass are about 67 meV, 160 meV and 290 meV, respectively. Additionally, the influence of the thermal treatment temperature on photoluminescence properties of CsPbBrxI3-x QDs glass was investigated in detail. These results will be of benefitting to their practical applications, such as display devices and WLEDs.

Improving luminescence characteristics of Ni2+ doped CsPbX3 (X = Br/I, I) quantum dots in borogermanate glass for wide color gamut display

For wide gamut backlight display application, main problems of CsPbX3 (X = Br/I, I) quantum dots (QDs) glasses as red emission materials are too long emission wavelengths, low luminescence intensity and worse uniformity. The full width at half maximum (FWHM) and decay time should also be considered. Here, Ni2+ doped CsPbX3 (X = Br/I, I) QDs in borogermanate glasses have been successfully fabricated by melt quenching and heat treatment. Transmittance, absorbance, photoluminescence (PL), PL excitation (PLE), PL decay and PL temperature characteristics are measured. By Ni2+ doping in the CsPbX3 (X = Br/I, I) QDs glasses (QDGs), PL intensity is significantly improved to higher level of 106–107 counts (enhanced by 1.6–1.7 times). The peak wavelength is adjusted to suitable range of 630–650 nm by double anion CsPb(Br/I)3 QDs. The uniformity is greatly improved by using suitable composition and concentration of CsPbX3 (X = Br/I, I) QDs. In addition, the FWHM of 32–46 nm is sufficiently narrow. The PL decay shows sufficiently short lifetime of less than 100 ns. The PL temperature dependence fitting shows large exciton binding energy 376–400 meV. For wide color gamut display application, we have used three primary colors with the standard blue, green and red lights in NTSC standard, and the red light has been replaced by using perovskite CsPbX3 (X = Br/I, I) QDGs. For the perovskite CsPbX3 (X = Br/I, I) QDGs emitted at 667 nm and 644 nm, the color gamut area has been increased by 11% and 9%, respectively. The results indicate that the red light QDG materials can be applied to wide color gamut display.

Effect of CaO on crystallization and photoluminescence of CsPbBr3 quantum dots germanium borate glass

In recent years, perovskite quantum dots (QDs) have emerged as a star of the materials world based on their extraordinary optical properties. Nevertheless, the photoluminescence performance (PL) and stability of QDs need to be further improved. In this work, CsPbBr3 QDs glass with high photoluminescence quantum yield (PLQY) and excellent hydro-stability was manufactured utilizing a high temperature fusion process and followed heat treatment. By adjusting the concentration of CaO, the PLQY of CsPbBr3 QDs glass increased from 7.78% to 64.52%. The consequence confirmed that CaO addition loosened the glass structure together with accelerated atomic migration and reorganization at lower polymerization states, thereby promoting the precipitation and growth of QDs. Significantly, after 33 days of immersion testing, the glass sample maintained excellent luminescence, which was attributed to the protection of the PbBr(OH) hydration layer. Furthermore, CsPbBr3 QDs glass maintained 71% of original PL intensity after three heating and cooling cycles, indicating that the prepared sample had good thermal stability. This work provided new insights into the relationship between network structure and CsPbBr3 QDs crystallization, and had certain reference value for improving the PL performance and water stability of CsPbBr3 QDs.

CsPbX3 (X = Cl/Br, Br, Br/I, I) quantum dots and copper ions co-doped boro-germanate glasses for long wavelength pass filters

We have investigated CsPbX3 (X = Cl/Br, Br, Br/I, I) quantum dots (QDs) co-doped with various metal ions in boro-germanate glass matrix for long wavelength pass filters. Transmittance, optical density (OD), photoluminescence (PL), PL excitation and PL decay have been evaluated. The working wavelength of filters has been extended to wide range from blue 475 nm to dark red 680 nm. Among these metal ions, only Cu2+ ions have obvious quenching or enhancement effect on the PL intensity and lifetime. Small amount Cu2+ of 0.005–0.3 mol% is used for PL quenching and maintaining excellent transmittance and optical density. Trace amounts of Cu2+ ions (≤0.01 mol.%) have obvious effect. The ratios of I0/I and τ0/τ are used to evaluate the quenching type and mechanism. The quenching/enhancement effect is different for different CsPbX3 (X = Cl/Br, Br, Br/I, I) QDs glasses (QDGs), showing strong correlation with the anionic composition (i.e. the bandgap) of CsPbX3 QDs. As Cu2+ concentration increases, the PL intensity is quenched for CsPb(Cl/Br)3 (Cl/Br=4:1, 2:1, 1:1), CsPbBr3 and CsPb(Br/I)3 (Br/I=1:1, 1:2, 1:4) QDGs, whereas it is enhanced for CsPbI3 QDG. The PL lifetime is decreased for CsPb(Cl/Br)3 (Cl/Br=4:1, 2:1, 1:1), CsPbBr3 and CsPb(Br/I)3 (Br/I=1:1) QDGs, whereas it is increased for CsPb(Br/I)3 (Br/I=1:2, 1:4) and CsPbI3 QDGs. An energy-dependent electron transfer (ET) mechanism is proposed to explain the quenching/enhancement. The ET and backward ET result in the quenching/enhancement in PL intensity and lifetime. The optical density (OD), absorption edge, transmittance, and transition wavelength have been evaluated for filter performance. The fabricated CsPbX3 (X = Cl/Br, Br, Br/I, I) QDGs can largely meet requirements for the long wavelength pass filters.

Efficient and tunable emission CsPbClxBr3-x quantum dot glass for overcoming the lack of cyan gap in WLED.

Recently, the photoluminescence (PL) performance and stability of cyan emission perovskite quantum dot (PQD) were found to be inferior to other color emitting PQDs, which greatly limits their practical applications. In this Letter, CsPbClxBr3-x PQD glass with excellent hydrothermal stability is successfully synthesized by a high-temperature melting method. Results review that the vacancy defects in [PbBr6]4- octahedra can be effectively compensated by excessive halogen doping, resulting in an improvement in the photoluminescence quantum yield (PLQY) of PQDs from 24.73% to 65.62%. In addition, compared to white light emitting diode (WLED) synthesized with commercial fluorescent powders, the introduction of CsPbCl2Br1 PQD glass effectively fills the cyan gap. Moreover, the WLED displays the color-rendering index (CRI) of 87 at correlated color temperature (CCT) of 5257 K, and the color gamut area reaches 126% of the National Television System Committee (NTSC). This work provides an effective way for improving the PL performance of PQDs and brings CsPbClxBr3-x PQD glass significant prospect in the optoelectronic applications.