Blue Light-emitting Diodes Research Articles

Aryl structural effect on the photoinitiation abilities of aryl glycine derivatives for polymerization upon exposure to blue light

AbstractThe design and development of photoinitiating systems applicable to visible light delivered from light‐emitting diodes (LEDs) have attracted increasing attention owing to the wide application of photopolymerization. In this study, four aryl glycine derivatives are designed and synthesized, and their applicability as visible light‐sensitive photoinitiators is thoroughly investigated. Specifically, the photoinitiation mechanism of these aryl glycine derivatives, when combined with iodonium salt, is investigated using steady‐state photolysis, fluorescence, and electron paramagnetic resonance spin trapping techniques. It is revealed that radicals can be generated from aryl glycine derivatives/iodonium salt combinations upon exposure to blue LEDs (410 and 445 nm) to induce free radical photopolymerization (FRP) of (meth)acrylates. Additionally, besides FRP, a photobase generator based on one of the investigated aryl glycine derivatives is synthesized and demonstrates the capability to initiate epoxy‐thiol polymerization under light irradiation. The remarkable photolatent characteristics demonstrate the significant potential in broadening the application of aryl glycine derivatives in controlled photopolymerization processes.

Comparing the Luminescence and Moisture Resistance of K3AlF6:Mn4+ Phosphor to Commercial Phosphors

Nowadays, red-emitting phosphors based on Mn4+ doped fluorides with a high color purity and a relatively short decay time can improve the optical performance of WLED. However, they are easily oxidized in humid environment and elevated temperatures. This is the reason why both the brightness and luminous efficiency of WLED quikly decreased. To solve this problem, KF was added throughout the K3AlF6:Mn4+ phosphor synthesis process (KKAFM). This work is focused on aging evaluation of the phosphors and comparing its performance with commercial phosphors (YAG:Ce3+, Sr2Si5N8:Eu2+). Thus, EL spectra of blue LED chips coated with the phosphors were investigated over time in an environment of 85 % RH and 85 oC. The results of EL spectra showed the improvement in the the reduction of the emission intensity of KKAFM. Aging tests of WLEDs using KKAFM and Sr2Si5N8:Eu2+ indicated that KKAFM phosphors exhibited a good stability, thus they can be used as a potential replacement for commercial red-emitting phosphors in WLEDs fabrication.

Efficient and stable CsPbBr3/Cs4PbBr6 composite powders passivated and encapsulated with a novel silicon-based ligand

The metal halide perovskite have garnered significant attention for their exceptional photoelectric properties. However, their inherent instability and the sharp decrease of photoluminescence quantum yield (PLQY) in the solid-state significantly limit their practical applications. Appropriate heterojunction structures or matrix encapsulation can efficiently improve the PLQY and stability of the metal halide perovskite. Herein, we report a new silicon-based ligand hydrolysis condensation encapsulation to synthesize CsPbBr3/Cs4PbBr6/BTESPA-x (CPB–Si-x) composite powders with improved luminescence properties and enhanced thermal stability. With the increase of BTESPA (from 0 to 150 μL), the efficient hydrolysis condensation process occurs on the surface of CsPbBr3/Cs4PbBr6. Finally, the abundant amino-silane groups in BTESPA bind to undercoordinated Pb2+, thereby suppressing the surface defect states and enhancing the PLQY from 34.3 % for CsPbBr3/Cs4PbBr6 (CPB) to 82.1 % for CPB-Si-5. Simultaneously, the thermal stability of CPB-Si-5 exhibits a 13 % improvement over that of CPB after undergoing thermal cycling. Furthermore, tricolor white light-emitting-diode (WLEDs) with high color rendering index were fabricated using on-chip blue LED with bright green-emissive CPB-Si-5 composite powder and red-emissive K2SiF6:Mn4+ phosphor, demonstrating the potential applicability of these powders in WLED backlight systems.

Shelf-Stable Green and Blue Quantum Dot Light-Emitting Diodes with High Efficiencies.

Quantum dot light-emitting diodes (QLEDs) are promising electroluminescent devices for next-generation display and solid-state lighting technologies. Achieving shelf-stable and high-performance QLEDs is crucial for their practical applications. However, the successful demonstration of shelf-stable QLEDs with high efficiencies is limited to red devices. Here, we developed a solution-based amine ligand exchange strategy to passivate the surfaces of optical ZnO (O-ZnO) nanocrystals, leading to suppressed exciton quenching at the green and blue QD/oxide interface. Furthermore, we designed new bilayered oxide electron-transporting layers consisting of amine-modified O-ZnO/conductive ZnO. This design simultaneously offers suppressed interfacial exciton quenching and sufficient electron transport in the green and blue QLEDs, resulting in shelf-stable green and blue devices with high efficiencies. Our devices exhibit neglectable changes in external quantum efficiencies (maximum external quantum efficiencies of 22.4% for green and 14.3% for blue) after storage for 270 days. Our work represents a step forward in the practical applications of QLED technology.

Multi-Mode Luminescence in Smart Near-Infrared Cr3+/Pr3+ Codoped SrGa12O19 Phosphors Induced by Three Distinct Excitation Mechanisms.

Near-infrared (NIR) phosphors have emerged as novel luminescent materials across various fields due to their unique advantages of high penetration and invisibility. However, there is currently a lack of intelligent NIR phosphors that can achieve multimode stimuli responsive for sensing applications. In this study, we employed a high-temperature solid-phase reaction to incorporate Pr3+ into Cr3+-doped gallate magnetite SrGa12O19 phosphor, yielding a multimode luminescent intelligent NIR phosphor. Also, due to the inherent cation vacancies and defects in the matrix, the material not only exhibits brighter photoluminescence but also exhibits distinct NIR mechanoluminescence at a lower load. Notably, Pr3+-doped SrGa12O19:Cr3+ also demonstrates extended persistent luminescence and thermoluminescence effects. Finally, we combined the phosphor with the blue LED chip to develop a new multifunctional NIR pc-LED. Leveraging NIR's unique penetrating ability, it can persist in biological tissues for prolonged periods, enabling optical inspection and offering a novel approach to password protection for anticounterfeiting measures. This intelligent NIR phosphor solution significantly expands the application potential of NIR light in food quality assessment and analysis.

Blue light irradiation suppresses oral squamous cell carcinoma through induction of endoplasmic reticulum stress and mitochondrial dysfunction

The therapeutic potential of blue light photobiomodulation in cancer treatment, particularly in inhibiting cell proliferation and promoting cell death, has attracted significant interest. Oral squamous cell carcinoma (OSCC) is a prevalent form of oral cancer, necessitating innovative treatment approaches to improve patient outcomes. In this study, we investigated the effects of 420 nm blue LED light on OSCC and explored the underlying mechanisms. Our results demonstrated that 420 nm blue light effectively reduced OSCC cell viability and migration, and induced G2/M arrest. Moreover, we observed that 420 nm blue light triggered endoplasmic reticulum (ER) stress and mitochondrial dysfunction in OSCC cells, leading to activation of the CHOP signal pathway and alterations in the levels of Bcl-2 and Bax proteins, ultimately promoting cell apoptosis. Additionally, blue light suppressed mitochondrial gene expression, likely due to its damage to mitochondrial DNA. This study highlights the distinct impact of 420 nm blue light on OSCC cells, providing valuable insights into its potential application as a clinical treatment for oral cancer.

Are phlebotomine sand flies (Diptera: Psychodidae) really attracted to UV-light sources?

Phlebotomine sand flies are the sole confirmed vector of leishmaniosis, a group of endemic and re-emerging diseases in southern European countries such as Spain. Light traps are the major surveillance method currently being employed. Nevertheless, color light attraction by sand flies remains mostly unknown. Following prior research, the effect of UV-LED light sources, and its synergic effect with different color lights has been evaluated employing a modified Flebocollect (FC) light trap model. Results suggest that female Phlebotomus perniciosus sand flies are more attracted to a FC trap lured with the combination of blue and UV LED light sources than commercial CDC (Center for Disease Control and prevention) traps (Bonferroni post-hoc test; p < 0.08; blue/UV mean = 0.50; CDC mean = 0.13), while the combination of red and UV modified-traps excel in capturing Sergentomyia minuta sand flies (Bonferroni post-hoc test; p < 0.04; blue/UV mean = 1.19; CDC mean = 0.66). However, based on our prior studies, incorporating UV light sources into sand fly traps does not seem to enhance their attractiveness, as it has not resulted in higher capture rates. These findings contribute to understanding how sand flies’ vision and light color detection is. Further research is recommended to standardize trap construction procedures and explore variations in different endemic regions according to different sand fly species.

Comparative Study on Temperature‐Dependent Internal Quantum Efficiency and Light–Extraction Efficiency in III‐Nitride–, III‐Phosphide–, and III‐Arsenide–based Light‐Emitting Diodes

This study attempts to understand and elucidate the factors limiting/determining the external quantum efficiency (EQE) of light‐emitting diodes (LEDs) depending on material systems, i.e., III‐arsenide (GaAs), III‐phosphide (AlGaInP), and III‐nitride (GaInN), via the temperature measurements (30–500 K). The behaviors of EQEs are investigated carefully in terms of the thermal droop and efficiency droop, revealing that the thermal droop in the AlGaInP and GaAs LEDs, while the efficiency droop in the GaInN LEDs, is a critical factor limiting the EQE. To deepen the insight, the EQE is separated into internal quantum efficiency (IQE) and light‐extraction efficiency (LEE). Further, the IQE is separated into radiative efficiency (RE) and injection efficiency (IE). The analysis shows that the LEE plays a significant role in the thermal droop for the AlGaInP and GaAs LEDs. Meanwhile, the IE and RE play a significant role in the EQE reduction of the blue and red LEDs at high temperatures and high current injection.

Blue‐Light‐Excitable Broadband Ca3Ga2Ge3O12:Cr3+,Ni2+ Phosphor for the Applications in NIR‐II Window

AbstractNear‐infrared (NIR) phosphor‐converted light‐emitting diode (pc‐LED) light sources in the second NIR window (NIR‐II, 1000–1700 nm) have sparked great interest for their emerging applications in non‐destructive detection and medical diagnostics fields. However, the development of efficient NIR‐II phosphors that can be excited by commercial blue LED chips remains a significant challenge, and thus impeding the applications of NIR pc‐LED. Herein, a blue‐light‐excitable broadband NIR‐II luminescence of Ni2+ is achieved upon incorporating Cr3+ and Ni2+ into the Ca3Ga2Ge3O12 (CGGO) host simultaneously. Through the energy transfer from Cr3+ to Ni2+, CGGO:Cr3+,Ni2+ phosphor presents the improved NIR‐II emission peaking at 1470 nm under 460 nm blue light excitation. The internal/external quantum efficiency values are significantly improved from 13.8%/3.3% to 24.6%/13.3% along with the enhanced luminescence thermal stability. Finally, a NIR pc‐LED is fabricated by combining CGGO:Cr3+,Ni2+ phosphor with 450 nm blue chip, and its potential applications in non‐destructive examination and biomedical imaging fields have been demonstrated. The strategy of Cr3+ and Ni2+ co‐doping solves the problem that Ni2+ luminescence cannot be effectively excited by blue light and provides the design insights to exploit more ultra‐broadband NIR pc‐LEDs based on blue LED chips.

Restraint of Nonradiative Recombination via Modulation of n-Phase Distribution through Interfacial Lithium Salt Insertion for High-Performance Pure-Blue Perovskite LEDs.

Quasi-two-dimensional perovskite has been widely used in blue perovskite light-emitting diodes. However, the performance of these devices is still hampered by random phase distribution, nonradiative recombination, and imbalanced carrier transport. In this work, an effective strategy is proposed to mitigate these limitations by inserting lithium salts at the interfaces between the hole transport layer (HTL) and the perovskite layer. The perovskite film on the inserted Li2CO3 layer exhibits reasonable n-value redistribution, which leads to the repressive nonradiation recombination and enhanced carrier transport. Moreover, the inserted Li2CO3 layer also improves the electrical conductivity of PEDOT:PSS and hinders indium ion diffusion from the PEDOT:PSS layer to the perovskite film, which inhibits exciton quenching and nonradiative recombination loss at the HTL/perovskite interface. Taking advantage of these merits, we have successfully fabricated efficient pure-blue PeLEDs with an external quantum efficiency of 6.2% at 472 nm and a luminance of 726 cd cm-2. The restraint of nonradiative recombination at the interface offers a promising approach for efficient pure-blue PeLEDs.

Structural, magnetic and photoluminescence properties of Zn-Ni ferrites synthesized by hydrothermal method

Nanocrystalline ZnxNi1-xFe2O4 (0 ≤ x ≤ 1.0) ferrites were synthesized by hydrothermal method. XRD analysis showed that all compositions crystallize with a cubic spinel-type structure with an average crystallite size in the range of 17–27 nm which corresponded to particle sizes obtained from TEM. The lattice parameter increased from 8.289 to 8.432 Å with increasing Zn content. The ZnxNi1-xFe2O4 nanoferrites exhibit superparamagnetic behaviour at room temperature (RT). The saturation magnetization (Ms) varies considerably with Zn content to reach a maximum value for Zn0.5Ni0.25Fe2O4 composition, i.e. 41.893 emu/g. The high Ms and magnetic moment values are attributed to cation distribution change. The electron spin resonance (ESR) results demonstrated g-values ranging between 2.005 and 2.621 which indicated strong exchange interaction between nanoparticles, type of morphology, and crystalline nature of particles. These low g-values make ZnxCo1-xFe2O4 nanoferrites suitable for applications in low-frequency devices. The Mössbauer spectroscopy results revealed the transition from ferromagnetic to paramagnetic state, by showing collapse of sestet to quadrupole doublet. The optical properties of the nanoferrites were investigated photoluminescence (PL) spectra. The broad visible emission band at 427 nm (2.90 eV), 471 nm (2.60 eV) and 520 nm (2.38 eV) were observed in all PL spectra. The electron spin resonance and photoluminescence results show that Zn-Ni ferrites are good candidates for blue LEDs and in gas sensing applications.

Observation of 2D-magnesium-intercalated gallium nitride superlattices

Since the demonstration of p-type gallium nitride (GaN) through doping with substitutional magnesium (Mg) atoms1,2, rapid and comprehensive developments, such as blue light-emitting diodes, have considerably shaped our modern lives and contributed to a more carbon-neutral society3–5. However, the details of the interplay between GaN and Mg have remained largely unknown6–11. Here we observe that Mg-intercalated GaN superlattices can form spontaneously by annealing a metallic Mg film on GaN at atmospheric pressure. To our knowledge, this marks the first instance of a two-dimensional metal intercalated into a bulk semiconductor, with each Mg monolayer being intricately inserted between several monolayers of hexagonal GaN. Characterized as an interstitial intercalation, this process induces substantial uniaxial compressive strain perpendicular to the interstitial layers. Consequently, the GaN layers in the Mg-intercalated GaN superlattices exhibit an exceptional elastic strain exceeding −10% (equivalent to a stress of more than 20 GPa), among the highest recorded for thin-film materials12. The strain alters the electronic band structure and greatly enhances hole transport along the compression direction. Furthermore, the Mg sheets induce a unique periodic transition in GaN polarity, generating polarization-field-induced net charges. These characteristics offer fresh insights into semiconductor doping and conductivity enhancement, as well as into elastic strain engineering of nanomaterials and metal–semiconductor superlattices13.

Analysis of the effects of various light spectra on microgreen species

ABSTRACT Light conditions, such as spectral composition, intensity and photoperiod, can affect the photosynthetic apparatus and content of beneficial bioactive compounds. The experiments realised under randomised experimental design tested seedlings of 21 genotypes, including 12 genotypes of the Brassicaceae family, lettuce, amaranth, onion, spinach, fenugreek and two beet and two basil genotypes, which were cultivated in three light environments under narrow-band red and blue light-emitting diodes (LEDs) and broad-band white LEDs. Responsiveness to light spectra was assessed based on fresh and dry weight, total chlorophyll and carotenoid contents and non-invasive assessment of specific compounds using fluorescence excitation ratios. In white light, we observed a higher fresh weight compared to that in monochromatic environments, especially compared to blue light. In most of the species, blue and white light had a positive effect on the concentration of chlorophyll and carotene in plants compared to red light. Blue light was associated with the highest values of chlorophyll excitation ratios, indicating a significant increase in flavonoids and anthocyanin contents. Individual microgreens responded differently in all assessed traits, especially in fluorescence ratios. We also observed the clustering of microgreens with similar responses to LED light spectra. In conclusion, in most plant species, multispectral white LEDs positively influenced quantitative and qualitative traits compared to the most frequently used red LEDs. Blue light slightly improved quality, but suppressed growth. Nevertheless, some species responded differently, emphasising the need to optimise the light to improve the microgreens’ production and nutritional value.

Vibration-mediated long-wavelength photolysis of electronegative bonds beyond S0–S1 and S0–T1 transitions

Photolysis is an attractive method in organic synthesis to produce free radicals through direct bond cleavage. However, in this method, specific irradiation wavelengths of light have been considered indispensable for excitation through S0–Sn or S0–Tn transitions. Here we report the photoinduced homolysis of electronegative interelement bonds using light at wavelengths much longer than theoretically and spectroscopically predicted for the S0–Sn or S0–Tn transitions. This long-wavelength photolysis proceeds in N–Cl, N–F, and O–Cl bonds at room temperature under blue, green, and red LED irradiation, initiating diverse radical reactions. Through experimental, spectroscopic, and computational studies, we propose that this “hidden” absorption is accessible via electronic excitations from naturally occurring vibrationally excited ground states to unbonded excited states and is due to the electron-pair repulsion between electronegative atoms.

Improvement of Bioactive Polyphenol Accumulation in Callus of Salvia atropatana Bunge.

Callus cultures of the Iranian medicinal plant Salvia atropatana were initiated from three-week-old seedlings on Murashige and Skoog (MS) medium supplemented with α-naphthaleneacetic acid (NAA) and various cytokinins. Although all tested hormonal variants of the medium and explant enabled callus induction, the most promising growth was noted for N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU)-induced calli. Three lines obtained on this medium (cotyledon line-CL, hypocotyl line-HL, and root line-RL) were preselected for further studies. Phenolic compounds in the callus tissues were identified using UPLC-MS (ultra-performance liquid chromatography-mass spectrometry) and quantified with HPLC (high-performance liquid chromatography). All lines exhibited intensive growth and contained twelve phenolic acid derivatives, with rosmarinic acid predominating. The cotyledon-derived callus line displayed the highest growth index values and polyphenol content; this was exposed to different light-emitting diodes (LED) for improving biomass accumulation and secondary metabolite yield. Under LED treatments, all callus lines exhibited enhanced RA and total phenolic content compared to fluorescent light, with the highest levels observed for white (48.5-50.2 mg/g dry weight) and blue (51.4-53.9 mg/g dry weight) LEDs. The selected callus demonstrated strong antioxidant potential in vitro based on the 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) tests. Our findings confirm that the S. atropatana callus system is suitable for enhanced rosmarinic acid production; the selected optimized culture provide high-quality plant-derived products.

Phlebotomine sand flies (Diptera: Psychodidae, Phlebotominae): Diversity of potential Leishmania vectors in northern Colombia

Phlebotomine sand flies are critical vectors of Leishmania parasites, impacting public health significantly. This study focused on assessing the diversity of sand flies in a rural area of El Carmen de Bolívar Municipality, northern Colombia, employing rarefaction curves and Hill numbers to understand potential vector communities and inform environmental management. From January 2018 to April 2019 (five samplings), sand flies were collected using CDC light traps with blue LED in domestic/peridomestic/sylvatic ecotopes, identifying species per Young and Duncan (1994) and Galati (2003). Hill numbers provided diversity estimates across samples, while Principal Component Analysis correlated with environmental factors with phlebotomine species presence and abundance. 8,784 phlebotomine individuals were collected; 56.4 % females and 43.6% males (ratio 3:2). These individuals belonged to eight species: Pintomyia evansi, Psychodopygus panamensis, Lutzomyia gomezi, Micropygomyia cayennensis, Evandromyia dubitans, Psathyromyia aclydifera, Pintomyia serrana, and Pintomyia rangeliana; with Pi. evansi being the most abundant species (74.39 %; 6,530 exemplars). The ANOVA showed no significant differences between phlebotomine sand flies abundances across ecotopes (p = 0.018). Species of epidemiological relevance as Pi. evansi and Lu. gomezi not show a positive correlation with environmental variables evaluated, only Ps. panamensis was positively correlated with precipitation. However, the study emphasizes the need for a continuous sand fly monitoring and research to enhance leishmaniasis control strategies, highlighting the necessity to expand knowledge on phlebotomine diversity and environmental interactions to understand vector ecology and disease dynamics better.

Differential expression of circRNAs during osteogenic/odontogenic differentiation of stem cells from apical papilla promoted by blue light-emitting diode.

Circular RNA (circRNA) is a key player in regulating the multidirectional differentiation of stem cells. Previous research by our group found that the blue light-emitting diode (LED) had a promoting effect on the osteogenic/odontogenic differentiation of human stem cells from apical papilla (SCAPs). This research aimed to investigate the differential expression of circRNAs during the osteogenic/odontogenic differentiation of SCAPs regulated by blue LED. SCAPs were divided into the irradiation group (4J/cm2) and the control group (0J/cm2), and cultivated in an osteogenic/odontogenic environment. The differentially expressed circRNAs during osteogenic/odontogenic differentiation of SCAPs promoted by blue LED were detected by high-throughput sequencing, and preliminarily verified by qRT-PCR. Functional prediction of these circRNAs was performed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) and the circRNA-miRNA-mRNA networks were also constructed. It showed 301 circRNAs were differentially expressed. GO and KEGG analyses suggested that these circRNAs were associated with some signaling pathways related to osteogenic/odontogenic differentiation. And the circRNA-miRNA-mRNA networks were also successfully constructed. CircRNAs were involved in the osteogenic/odontogenic differentiation of SCAPs promoted by blue LED. In this biological process, circRNA-miRNA-mRNA networks served an important purpose, and circRNAs regulated this process through certain signaling pathways.

In Situ Synthesis of CsPbX3/Polyacrylonitrile Nanofibers with Water-Stability and Color-Tunability for Anti-Counterfeiting and LEDs.

Inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (PQDs) have attracted widespread attention due to their excellent optical properties and extensive application prospects. However, their inherent structural instability significantly hinders their practical application despite their outstanding optical performance. To enhance stability, an in situ electrospinning strategy was used to synthesize CsPbX3/polyacrylonitrile composite nanofibers. By optimizing process parameters (e.g., halide ratio, electrospinning voltage, and heat treatment temperature), all-inorganic CsPbX3 PQDs have been successfully grown in a polyacrylonitrile (PAN) matrix. During the electrospinning process, the rapid solidification of electrospun fibers not only effectively constrained the formation of large-sized PQDs but also provided effective physical protection for PQDs, resulting in the improvement in the water stability of PQDs by minimizing external environmental interference. Even after storage in water for over 100 days, the PQDs maintained approximately 93.5% of their photoluminescence intensity. Through the adjustment of halogen elements, the as-obtained composite nanofibers exhibited color-tunable luminescence in the visible light region, and based on this, a series of multicolor anti-counterfeiting patterns were fabricated. Additionally, benefiting from the excellent water stability and optical performance, the CsPbBr3/PAN composite film was combined with red-emitting K2SiF6:Mn4+ (KSF) on a blue LED (460 nm), producing a stable and efficient WLED device with a color temperature of around 6000 K and CIE coordinates of (0.318, 0.322). These results provide a general approach to synthesizing PQDs/polymer nanocomposites with excellent water stability and multicolor emission, thereby promoting their practical applications in multifunctional optoelectronic devices and advanced anti-counterfeiting.

71‐1: CMOS Backplane Technology and Its Challenge for µLEDoS AR/XR Display

This paper introduces the latest CMOS (Complementary Metal‐Oxide‐Silicon) backplane technology for µLEDoS AR/XR display engines. The backplane supports a display resolution of 1,280RGB x 720 and has been implemented on a 28nm Fully Depleted Silicon on Insular (FD‐SOI) CMOS process in order to meet the requirements such as performance, power, and pixel size. The area of a single pixel is 4.95µm x 4.95µm achieving higher than 5,000 PPI in RGB‐color mode. Each pixel contains 3 independent sub‐pixel drivers and one dependent driver assigned for a red LED. Each sub‐pixel driver includes a 10‐bit video SRAM memory, PWM (Pulse Width Modulation) control logic block, a constant current generator, and LED driver stage to drive red, green, or blue LEDs. The backplane also integrates necessary image processing functions such as De‐mura compensation, dead‐pixel compensation, and digital gamma generation. The top surface of the backplane wafer is also prepared for a wafer‐to‐wafer hybridization bonding between the CMOS wafer and an LED wafer.

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).