Efficient White Light-emitting Diodes Research Articles

Fine-Tuning Optoelectronic Features in Organic-Inorganic Hybrid Metal Halides: A Focus on the Phenylbutanammonium Series.

Extensive research has been dedicated to exploring the potential applications of organic-inorganic hybrid metal halides in optoelectronics. This study presents findings on three metal halides based on phenylbutanammonium (PBA). Specifically, (PBA)2MnBr4(H2O)2 and (PBA)2Sn(IV)Cl6 exhibit zero-dimensional structures with P21/c and Pnma space groups, respectively, while (PBA)2Sn(II)Br4 features a two-dimensional structure with P1̅ space group. Under UV excitation, (PBA)2MnBr4(H2O)2 exhibits double emission arising from the 4T1 → 6A1 transitions of Mn2+ in two distinct coordination environments. The emission spectrum of (PBA)2SnCl6 aligns with that of PBACl, suggesting that the luminescence originates from the organic component. The yellow emission of (PBA)2SnBr4 is attributed to the self-trapped excitons. This study introduces the PBA series of compounds, revealing that varying metal ions and halogen combinations can adjust the structural dimensions and influence optical properties. The insights gained from this work serve as a guide for the preparation of efficient white light-emitting diodes.

Revealing the Structure-Luminescence Relationship in Robust Sn(IV)-Based Metal Halides by Sb3+ Doping.

Low-dimensional hybrid metal halides are an emerging class of materials with highly efficient photoluminescence (PL), but the problems of poor stability remain challenging. Sn(IV)-based metal halides show robust structure but exhibit poor PL properties, and the structure-luminescence relationship is elusive. Herein, two Sn(IV)-based metal halides (compounds 1 and 2) with the same constituent ((C6H16N2)SnCl6) but different crystal structures have been prepared, which however show poor PL properties at room temperature due to the absence of active ns2 electrons. To improve materials' PL properties, Sb3+ with active 5s2 electrons was embedded into the lattice of Sn4+-based hosts. As a result, efficient emissions were achieved for Sb3+-doped compounds 1 and 2 with a maximum PL efficiency of 14.28 and 62%, respectively. Experimental and calculation results reveal that the smaller distorted lattice structure of the host could result in the blueshift of the emission from Sb3+. Thus, a tunable color from red to orange was realized. Benefiting from the broadband efficient emission from Sb3+-doped compound 2, an efficient white light-emitting diode with a high color rendering index of up to 92.3 was fabricated to demonstrate its lighting application potential. This work promotes the understanding of the influence of robust Sn(IV)-based host lattice on the PL properties of Sb3+, advancing the development of environmentally friendly, low-cost, and high-efficiency Sn(IV)-based metal halides.

Near-Unity and High Anti-Thermal Quenching Red Luminescence from One-Dimensional Hybrid Manganese Chloride for Efficient and Stable White Light-Emitting Diode

The discovery of novel Mn2+-based metal halides with excellent luminescence properties and thermostability is particularly of great importance for solid-state lighting (SSL). Herein, a novel one-dimensional hybrid manganese chloride (TMA)MnCl3...

Polymer-doped perovskite nanocrystals for efficient single active layer white light-emitting diodes through energy transfer

White-light emitting diodes (WLEDs) are mainly constructed by stacking different light-emitting layers with complementary emission spectra. However, this not only requires complex device fabrication processes but also needs comprehensive charge transport regulation, limiting the development and application of WLEDs. In this work, efficient single-layer WLEDs are achieved via doping tiny amount of a red polymer poly[[9-(1-octylnonyl)-9H- carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5 thiophenediy (PCDTBT8) into the perovskite nanocrystals (NCs) matrix. The 490 nm sky blue perovskite nanocrystals (FA0.08Cs0.92PbBr2Cl) are synthesized and passivated with a short-chain ligand 3-methoxyphenethylamine (MPEA), which enhances luminance and stability at high bias. Energy transfer from NCs to PCDTBT8 significantly enhances red-light emitting in the range from 600 to 750 nm, enabling white-light emission. By tuning of the NCs:PCDTBT8 weight ratio from 400:1 to 150:1, a continuous transition of emission from cold white-light to warm white-light is achieved. With the NCs:PCDTBT8 weight ratio of 250:1, a standard white-light emission with the Commission Internationale de l’Eclairage (CIE) coordinates of (0.33, 0.33), a luminance of 752 cd/m2 and an external quantum efficiency (EQE) of 1.59% are obtained at a fairly low voltage of 4.8 V.

Uniform nucleation and growth of Cs3Cu2I5 nanocrystals with high luminous efficiency and structural stability and their application in white light-emitting diodes.

Copper-based ternary halide composites have attracted great attention due to their superior chemical stability and optical properties. Herein, we developed an ultrafast high-power ultrasonic synthesis strategy to realize the uniform nucleation and growth of highly luminescent and stable Cs3Cu2I5 nanocrystals (NCs). The as-synthesized Cs3Cu2I5 NCs show uniform hexagonal morphology with an average mean size of 24.4 nm and emit blue light with a high photoluminescence quantum yield (PLQY) of ∼85%. Moreover, the Cs3Cu2I5 NCs exhibit a remarkable stability during continuous eight times heating/cooling cycling tests (303-423 K). We also demonstrated an efficient and stable white light-emitting diode (WLED) with a high luminous efficiency (LE) of 41.5 lm W-1 and a Commission Internationale de l'Eclairage (CIE) color coordinate of (0.33,0.33).

Efficient single-component white light emitting diodes enabled by lanthanide ions doped lead halide perovskites via controlling Förster energy transfer and specific defect clearance

Currently, a major challenge for metal-halide perovskite light emitting diodes (LEDs) is to achieve stable and efficient white light emission due to halide ion segregation. Herein, we report a promising method to fabricate white perovskite LEDs using lanthanide (Ln3+) ions doped CsPbCl3 perovskite nanocrystals (PeNCs). First, K+ ions are doped into the lattice to tune the perovskite bandgap by partially substituting Cs+ ions, which are well matched to the transition energy of some Ln3+ ions from the ground state to the excited state, thereby greatly improving the Förster energy transfer efficiency from excitons to Ln3+ ions. Then, creatine phosphate (CP), a phospholipid widely found in organisms, serves as a tightly binding surface-capping multi-functional ligand which regulates the film formation and enhances the optical and electrical properties of PeNC film. Consequently, the Eu3+ doped PeNCs based-white LEDs show a peak luminance of 1678 cd m-2 and a maximum external quantum efficiency (EQE) of 5.4%, demonstrating excellent performance among existing white PeNC LEDs from a single chip. Furthermore, the method of bandgap modulation and the defect passivation were generalized to other Ln3+ ions doped perovskite LEDs and successfully obtained improved electroluminescence (EL). This work demonstrates the comprehensive and universal strategies in the realization of highly efficient and stable white LEDs via single-component Ln3+ ions doped PeNCs, which provides an optimal solution for the development of low-cost and simple white perovskite LEDs.

High-performance CsPbBr3@Cs4PbBr6/SiO2 nanocrystals via double coating layers for white light emission and visible light communication

Owing to their outstanding optoelectronic properties, all-inorganic CsPbBr3 perovskite nanocrystals (NCs) are regarded as excellent materials for various optoelectronic applications. Unfortunately, their practical applications are limited by poor stability against water, heat, and polar solvents. Here, we propose a facile synthesis strategy for CsPbBr3@Cs4PbBr6 NCs via tetraoctylammonium bromide ligand induction at room temperature. The resulting CsPbBr3@Cs4PbBr6 NCs show a high photoluminescence quantum yield of 94%. In order to prevent Cs4PbBr6 from being converted back to CsPbBr3 NCs when exposed to water, a second coating layer of SiO2 is formed on the surface of the CsPbBr3@Cs4PbBr6 NCs by the facile hydrolysis of tetramethoxysilane. The resulting CsPbBr3@Cs4PbBr6/SiO2 NCs with their double coating structure have outstanding stability against not only a polar solvent (ethanol) but also water and heat. The as-prepared CsPbBr3@Cs4PbBr6/SiO2 NCs serve as green emitters in efficient white light-emitting diodes (WLEDs) with a high color rendering index (CRI) of 91 and a high power efficiency 59.87 lm W−1. Furthermore, the use of these WLEDs in visible light communication (VLC) results in a maximum rate of 44.53 Mbps, suggesting the great potential of the reported methods and materials for solid-state illumination and VLC.

Quantum Dot to Nanorod Transition for Efficient White-Light-Emitting Diodes with Suppressed Absorption Losses

Colloidal nanocrystals have great potential for next-generation solid-state lighting due to their outstanding emission and absorption tunability via size and morphology, narrow emission linewidth, and high photoluminescence quantum yield (PLQY). However, the losses due to self- and interabsorption among multitudes of nanocrystals significantly decrease external quantum yield levels of light-emitting diodes (LEDs). Here, we demonstrate efficient white LEDs via CdSe/CdS dot to “dot-in-rod” transition that enabled a large Stokes shift of 780 meV and significantly reduced absorption losses when used in conjunction with near-unity PLQY ZnCdSe/ZnSe quantum dots (QDs) emitting at the green spectral range. The optimized incorporation of nanocrystals in a liquid state led to the white LEDs with an ultimate external quantum efficiency (EQE) of 42.9%, with a net increase of EQE of 10.3% in comparison with white LEDs using CdSe/CdS dots. Therefore, combinations of nanocrystals with different nanomorphologies hold high promise for efficient white LEDs.

Photoluminescence properties and energy transfer in the Sm3+ and Eu3+ co-doped Ca3Bi(PO4)3 red phosphor

Red phosphors play a vital role in improving the color quality and luminous efficiency of white light-emitting diodes (w-LED). However, it is still a challenge to develop red phosphors with higher efficiency, higher color purity, and better matching near-ultraviolet (n-UV) chips. In this paper, a series of Sm3+, Eu3+ co-doped Ca3Bi(PO4)3 (CBP) were successfully prepared by the high temperature solid-state reaction method. The crystal structure, photoluminescence properties, and energy transfer mechanism were investigated in detail. The maximum doping concentration of Eu3+ in CBP was confirmed to be 30 mol% in this research considering the structural instability with higher doping concentration. Under 393 nm n-UV excitation, CBP: 8 mol% Sm3+, 25 mol% Eu3+ phosphor exhibit excellent red-lighting emission at 612 nm with high color purity of 99.28 %. More impressively, the effective excitation wavelength of Sm3+, Eu3+ co-doped CBP phosphors is extended to 391–403 nm due to energy transfer from Sm3+ to Eu3+. Moreover, the energy transfer mechanism is rationalized through dipole–dipole interaction as indicated via decay kinetics studies. The fabricated w-LED emits white light, which has high color rendering index (CRI = 86.0) at color coordinate temperature CCT = 6985 K and luminous efficiency (66 lm/w). The phosphor shows excellent thermal stability, and the fluorescence intensity to temperature 423 K can retain 75.98 % of its initial value of room temperature. These results indicate that this phosphor with high-efficiency red-emitting is a promising candidate as a red component for n-UV LED application.

Benefits of using TiO2 quantum dots in producing low-cost and high-quality white light-emitting diodes

Quantum dots (QDs) is considered as a potential material for the improvement of light-emitting diodes (LEDs). However, different from the traditional phosphor materials, they have unique scattering and absorption properties affected by their several nanometers sizes, which makes their application in the production of LED confront more challenges. In addition to this, their influences on QDs-converted LEDs (QCLEDs) are rarely investigated. So as to propose solutions for those problems, in this article, we experimentally and theoretically investigated the impacts of titanium dioxide (TiO 2 )QDs’ scattering and absorption on the light quality of QCLEDs by drawing a thorough comparison between their properties and the traditional yttrium aluminum garnet phosphors characteristics. The outcomes showed that QCLEDs have poor radiant efficacy and stability due to QDs’ strong characteristic of absorption (reabsorption) while their weak scattering property causes a low uniformity in correlated color temperature (CCT). For achieving high efficiency and stability white LEDs, we highly suggest using QDs with a low concentration to get reductions in the reabsorption and total internal reflection losses. With 0.05 concentration of TiO 2 nanoparticles (TiO 2 NPs), the white LEDs can simultaneously achieve a high CCT (approximately 7500 K) and a high color rendering index (around 85).

High Luminous Efficacy Phosphor-Converted Mass-Produced White LEDs Achieved by AlN Prebuffer and Transitional-Refraction-Index Patterned Sapphire Substrate.

Constant advance in improving the luminous efficacy (ηL) of nitride-based light-emitting diodes (LEDs) plays a critical role for saving measurable amounts of energy. Further development is motivated to approach the efficiency limit for this material system while reducing the costs. In this work, strategies of using thin AlN prebuffer and transitional-refraction-index patterned sapphire substrate (TPSS) were proposed, which pushed up the efficiency of white LEDs (WLEDs). The AlN prebuffer was obtained through physical vapor deposition (PVD) method and TPSS was fabricated by dry-etched periodic silica arrays covered on sapphire. Devices in mass production confirmed that PVD AlN prebuffer was able to improve the light output power (φe) of blue LEDs (BLEDs) by 2.53% while increasing the productivity by ~8% through shortening the growth time. Additionally, BLEDs on TPSS exhibited an enhanced top ηext of 5.65% in contrast to BLEDs on the conventional PSS through Monte Carlo ray-tracing simulation. Consequently, φe of BLEDs was experimentally enhanced by 10% at an injected current density (Jin) of 40 A/cm2. A peak ηL of 295.2 lm/W at a Jin of 0.9 A/cm2 and the representative ηL of 282.4 lm/W at a Jin of 5.6 A/cm2 for phosphor-converted WLEDs were achieved at a correlated color temperature of 4592 K.

Exciplex-Forming Systems of Physically Mixed and Covalently Bonded Benzoyl-1H-1,2,3-Triazole and Carbazole Moieties for Solution-Processed White OLEDs.

Using the newly designed exciplex-forming 1,2,3-triazole-based acceptors with fast and efficient singlet → triplet intersystem crossing (ISC) processes, carbazole and benzoyl-1H-1,2,3-triazole derivatives were synthesized by Dimroth-type 1,2,3-triazole ring formation and Ullmann–Goldberg C–N coupling reactions. Due to the exciplex formation between covalently bonded electron-donating (carbazole) and 1,2,3-triazole-based electron-accepting moieties with small singlet-triplet splitting (0.07–0.13 eV), the compounds exhibited ISC-assisted bluish–green thermally activated delayed fluorescence. The compounds were characterized by high triplet energy levels ranging from 2.93 to 2.98 eV. The most efficient exciplex-type thermally activated delayed fluorescence was observed for ortho-substituted carbazole-benzoyl-1H-1,2,3-triazole which was selected as a host in the structure of efficient solution-processed white light-emitting diodes. The best device exhibited a maximum power efficiency of 10.7 lm/W, current efficiency of 18.4 cd/A, and quantum efficiency of 7.1%. This device also showed the highest brightness exceeding 10 thousand cd/m2. Usage of the exciplex-forming host allowed us to achieve a low turn-on voltage of 3.6 V. High-quality white electroluminescence was obtained with the close to nature white color coordinates (0.31, 0.34) and a color rendering index of 92.

Perovskite nanocrystals-polymer composites with a micro/nano structured superhydrophobic surface for stable and efficient white light-emitting diodes

Metal halide perovskite nanocrystals (PNCs) offer excellent optoelectronic properties for light-emitting diodes (LEDs). However, the low chemical stability against water hinders their practical application. Herein, we develop a phase separation strategy to realize highly luminescent PNC-polymer composites with a superhydrophobic micro/nano structured surface. Ethyl α-cyanoacrylate (ECA) monomers and octavinyloctasilasesquioxane (OVS) are added into the PNC toluene solution together. Due to high reactivity of ECA toward H2O, the poly (ethyl α-cyanoacrylate) (PECA) polymer matrix (first phase) is initially formed via a rapid anion polymerization reaction in a humid environment. As the evaporation of toluene, the OVS is then condensed into the micro/nano-scale protrusions (second phase) on the PECA substrate because of the strong Si-O bonds between OVS molecules, and the PNCs are uniformly encapsulated within the two polymers. We find that besides the increased quantum efficiency, the chemical stability of the resulting PNC-PECA-OVS composites is remarkably enhanced. Immersing the superhydrophobic composites into water, the PL intensity still maintains ∼ 60% even after 1000 h. In contrast, the PL emission of pristine PNCs is completely quenched after only 10 min. By curing the green PNC-polymer composites with commercially available red-emitting phosphors on a blue-emitting InGaN chip, we demonstrate a long-term stable and efficient white LED with a high power efficiency of ∼ 93 lm/W and almost constant color-correlated temperature (CCT).

In situpassivation of Pb0traps by fluoride acid-based ionic liquids enables enhanced emission and stability of CsPbBr3nanocrystals for efficient white light-emitting diodes

A great hurdle restricting the optoelectronic applications of cesium lead halide perovskite (CsPbX3) nanocrystals (NCs) is due to the uncoordinated lead atoms (Pb0) on the surface, where most attempts to address the challenges in the literature depend on complicated post-treatment processes. Here we report a simple in situ surface engineering strategy to obtain highly fluorescent and stable perovskite NCs, wherein the introduction of the multifunctional additive 1-butyl-3-methyl-imidazolium tetrafluoroborate ([Bmim]BF4) can significantly eliminate the Pb0 traps. The photoluminescence quantum yield (PLQY) of the as-synthesized NCs was improved from 63.82% to 94.63% due to the good passivation of the surface defects. We also confirm the universality of this in situ passivation pathway to remove Pb0 deep traps by using fluoride acid-based ionic liquids (ILs). Due to the high hydrophobicity of the cations of ILs, the as-prepared CsPbBr3 NCs exhibit robust water resistance stability, maintaining 67.5% of the initial photoluminescence (PL) intensity after immersion in water for 21 days. A white light emitting diode (LED), assembled by mixing the as-synthesized CsPbBr3 NCs and red K2SiF6:Mn4+ phosphors onto a blue chip, exhibits high luminous efficiency (100.07 lm W-1) and wide color gamut (140.64% of the National Television System Committee (NTSC) standard). This work provides a promising and facile technique to eliminate the Pb0 traps and improve the optical performance and stability of halide perovskite NCs, facilitating their applications in optoelectronic fields.

One-pot synthesis of double silane-functionalized carbon dots with tunable emission and excellent coating properties for WLEDs application

Silane-functionalized carbon dots (SiCDs) can be exploited as effective color converting materials for the solid-state light-emitting devices. However, most of SiCDs reported thus far have shown photoluminescence emissions in the blue and green spectral range, which limit them to construct an efficient white light-emitting diodes (WLEDs) due to the lack of long-wavelength emission. Herein, a series of double silane-functionalized carbon dots (DSiCDs) were prepared via a one-step solvothermal method. The results show that the organic functional group of the silane has great influence on the optical properties of DSiCDs and the number of alkoxy group in the silane has great influence on coating properties of DSiCDs. In addition, the DSiCDs prepared by (3-aminopropyl)triethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine with molar ratio of 7:3 show excellent optical properties with the maximum emission at 608 nm under 570 nm excitation. Furthermore, they can be completely cured within 1 h at room temperature to form fluorescent coating with high stability and strong adhesion to the substrate. Together with their excellent optical and coating properties, they can be directly coated on LED chips to prepare WLEDs, with a CIE coordinate of (0.33,0.31), color rendering index of 81.6, and color temperature of 5774 K.

Quantum-Rod On-Chip LEDs for Display Backlights with Efficacy of 149lmW-1 : A Step toward 200lmW-1.

Efficient white light-emitting diodes (LEDs) with an efficacy of 200lmW-1 are much desirable for lighting and displays. The phosphor-based LEDs in use today for display applications offer poor color saturation. Intensive efforts have been made to replace the phosphor with quantum-dot-based downconverters, but the efficiency and stability of these devices are still in their infancy. Quantum rods (QRs), nanoparticles with an elongated shape, show superior properties such as relatively larger Stokes shifts, polarized emission, and high light out-coupling efficiency in the solid-state. However, these QRs usually suffer from poor optical quality for PL wavelengths <550nm. Herein, a gradient alloyed CdSe/Znx Cd1- x S/ZnS and CdSe/CdS/ZnS core/shell/shell QR downconverters showing high efficacy LEDs covering a wide color gamut are reported. These QRs show high stability and a precisely tunable photoluminescence peak. The engineered shell thickness suppresses energy transfer and thus maintains the high quantum yield in the solid-state (81%). These QR-based LEDs attain an efficacy of 149lmW-1 (@10mA) andwide color gamut (118% NTSC), which is exceedingly higher than state-of-the-art quantum dots and phosphor-based on-chip LEDs.

Benefits of using TiO2 Quantum Dots in producing low-cost and high-quality white LEDs

Quantum dots (QDs) is considered as a potential material for the improvement of light-emitting diodes (LEDs). However, different from the traditional phosphor materials, they have unique scattering and absorption properties affected by their several nanometers sizes, which makes their application in the production of LED confronts more challenges. In addition to this, the influence of QDs on QDs-converted LEDs (QCLEDs) is barely studied. In order to propose solutions for those problems, in this article, we carried out experimental and theoretical investigation of the effect of TiO 2 QDs’ scattering and absorption on the optical performance of QCLEDs by comparing their properties with the traditional yttrium aluminum garnet phosphors’. The results showed that the strong absorption (reabsorption) of QDs is the cause of low radiant efficacy and stability of QCLEDs, and their weak scattering ability results in a low color homogeneity. For achieving high efficiency and stability white LEDs, we highly suggest using a low QD concentration to get reductions in the reabsorption loss and the total internal reflection loss. With 0.05 concentration of TiO 2 NPs, the white LEDs can achieve a high CCT of ∼ 7500 K and a high CRI of ∼ 85 simultaneously. Moreover, this TiO 2 concentration can also increase the luminous intensity by ∼ 31%. Therefore, we believe that the study can propose a potential approach to the production of low-cost CDs-based LEDs with high performance in a near future.

Octupolar Acrylonitrile-Bridged 2D-Conjugated Polymers Enable Bright Far-Red Emission with Intense Two-Photon Absorption via Alkoxylation Chemistry.

Herein, alkoxylation chemistry is introduced as a "one-stone-three-birds" solution for exploring a new family of highly-fluorescent octupolar 2D-conjugated organic polymers/frameworks (OCOPs/OCOFs) combining far-red emission, high fluorescence quantum yield (QY), and strong two-photon absorption (TPA). Both alkoxy-substituted OCOP and OCOF comprising acrylonitrile-bridged strongly-coupled donor3-(acceptor core) chromophores densely packed in either disordered or ordered forms, exhibit significantly redshifted emission. They produce high QY of 22.2% and 27.8% in tetrahydrofuran, large TPA cross section of 600 and 1124 GM, and 2-3 folds and 15-30 folds that of non-alkoxylate amorphous counterpart respectively. Combined theoretical and experimental studies reveal unique "one-stone-three-birds" role of the alkoxylation in realizing red-shifted-emission, improved QY and TPA enabled by inducing steric hindrance effect for weakened π-π stacking, and triggering p-π conjugation effect for electronically engineering octupolar chromophores, while the crystalline engineering enables enforced coplanarity conformation and improved π-electron delocalization for further improved QY and TPA. The robust and biocompatible pentoxy-substituted polymer can be used not only as metal-free red-emissive phosphor for efficient warm white light-emitting diodes, but also as efficient two-photon fluorescence probes for bio-imaging.

Near-unity blue-orange dual-emitting Mn-doped perovskite nanocrystals with metal alloying for efficient white light-emitting diodes

The tunable dual-color emitting Mn2+ doped CsPbCl3-xBrx nanocrystals (NCs) with near-unity photoluminescence quantum yield (PL QY) were synthesized through post-treatment of metal bromide at room temperature for fabrication of efficient warm white light-emitting diodes (WLEDs). Especially, the CdBr2 treated blue-orange emitting Mn doped NCs with various Mn/Pb molar feed ratios exhibit higher PL QY of 97% and longer Mn2+ PL lifetime of 0.9 ms. It is surprisingly found that the X-ray diffraction peak at 31.9° is almost not changed with increasing Br composition, meaning formation of metal alloying due to incorporation of amount of divalent cation in NCs. The strong and stable Mn2+ PL at temperature ranging from 80 K to 360 K are revealed and the temperature-dependent energy transfer efficiencies in Mn2+ doped CsPbCl1.5Br1.5 NCs are obtained. The enhancement mechanism of Mn2+ PL QY was attributed to improved energy transfer from exciton to Mn2+ d–d transition and suppressed defect state density after post-treatment. The efficient warm WLEDs with color rendering index of 90 and luminous efficacy of 92 lm/W at 10 mA were fabricated by combining blue-orange dual-emitting Mn2+ doped CsPbCl3-xBrx@SiO2 and green emissive CsPbBr3@SiO2 NCs with violet GaN chips.

Enhanced stability of CsPbBr3 Quantum Dots by anchoring on the hierarchical three-dimensional layered double hydroxide

The poor stability of all-inorganic perovskite quantum dots (QDs) limits its application in the field of optoelectronics although it possesses prominent luminescent properties. Herein, we proposed a selective nucleation-growth strategy through anchoring the CsPbBr3 QDs on the aminated hierarchical three-dimensional layered double hydroxide (A3D-LDH). The strong interaction between the amino group and Pb2+ endows the anchoring effect of A3D-LDH. Coordinated with the isolation effect of flower-like structure, the A3D-LDH/CsPbBr3 composites exhibited high solid photo-luminescence quantum yield (82.35%) and enhanced stability against the adverse environment (humidity air, irradiation, and heat), which is attributed to restricted aggregation and surface passivation of CsPbBr3 QDs. Benefiting from the advantageous properties, an efficient white light-emitting diode (LED) is fabricated by introducing A3D-LDH/CsPbBr3 composites as green phosphors with color coordinates (0.349, 0.349) at a correlated color temperature of 4841 K. We believe that our method offered a promising candidate for solid-state lighting and display.