摘要:Organic-inorganic hybrid manganese halides are ideal narrow-band green light materials, but their encapsulated LED devices rapidly degrade after being lit, making them unsuitable for applications. This paper reports on an organic-inorganic hybrid manganese halide, (1-mPQBr)₂MnBr₄, and demonstrates the good light output stability of its encapsulated LED. In addition, to address the issue of weak luminescence, optimized evaporation synthesis methods and metal ion doping techniques have been proposed. Among these, the sample doped with 10% Li exhibited the highest luminescence intensity, which was a 28% improvement compared to the traditional evaporation method. This study found that the improved evaporation method enhanced the material’s absorption of blue light; the ion substitution method altered the crystal structure, thereby increasing the luminescence intensity. The white light LED encapsulated by (1-mPQBr)₂MnBr₄ has a color gamut coverage of 106% NTSC, with a luminous efficacy of 112 lm/W at a drive current of 10 mA. This discovery opens the door for the application of organic-inorganic hybrid manganese halides in the field of high-color-gamut displays.
关键词:Organic-inorganic metal halides;Green phosphors;photoluminescence;LED applications
摘要:With the development of flexible wearables and self-driven sensors, triboelectrification-induced electroluminescence (TIEL) materials have attracted significant attention due to their unique mechanical-light energy conversion. Among them, doped zinc sulfide (ZnS) materials have become the hotspot due to their high luminescence efficiency, long lifetime and tunable luminescence. This article reviews the recent progress of doped ZnS films on triboelectrification-induced electroluminescence in terms of working mechanism, performance optimization and practical applications. First, the luminescence mechanism of doped ZnS, the structure and working principle of doped ZnS films on triboelectrification-induced electroluminescence are explained and introduced. Next, strategies in literatures are overviewed and commented on how to improve the luminescence intensity, and the progress of various application based on this system in recent years is discussed. Finally, we given an outlook on the development trend and application prospect of doped ZnS films on triboelectrification-induced electroluminescence.
关键词:doped zinc sulfide;triboelectrification-induced electroluminescence;flexible wearables;self-driven sensors;thin films
摘要:Due to its excellent field emission properties, stable chemical properties, and ease of low-cost large-area preparation, zinc oxide nanowire has important applications in large-area cold cathode electron source devices. Many works on the field emission mechanism, performance modulation, and electron source device applications of ZnO nanowire cold cathodes have been reported in the past decades. To further advance the practical applications of ZnO nanowire cold cathodes, it is necessary to summarize the current status and challenges of their development. In this paper, we review the progress of ZnO nanowire cold cathode in aspects of field emission property, gate structure design and fabrication, and the X-ray source application, from the point of view of the performance requirements of large-area cold cathode electron source. Finally, a perspective on future research trends and challenges is given.
关键词:ZnO nanowire;cold cathode;flat panel electron source;flat panel X-ray source
摘要:Scintillators have numerous applications in the fields of precision detection of high-energy physics, nuclear physics research, medical diagnosis, industrial flaw detection, and national defense security monitoring. However, traditional single crystal scintillators are difficult to realize large-scale preparation due to their complex processes, high costs, and limited volume size. In recent years, glass scintillators have stood out due to their highly mature production processes, low costs, good efficient luminescence, and excellent plasticity. This paper elaborates on the luminescence mechanism of glass scintillators and enumerates key parameters for evaluating their scintillation performance. Based on their components and structural characteristics, glass scintillators are mainly classified into oxide glass scintillators, halide glass scintillators, and micro/nano-crystalline composite glass scintillators. This review focuses on the overview of the latest research results and development trend of glass scintillator for X-ray, and summarizes the high-density glass scintillator. Finally, the future development trend of glass scintillator for X-ray is summarized and outlooked.
摘要:With the rapid development of new display and lighting technologies, the demand for efficient and stable green light emitting devices has been increasing. Perovskite light-emitting diodes (PeLEDs) have demonstrated significant potential in optoelectronic displays and lighting applications, owing to their high luminous efficiency, low fabrication costs, and high color purity. As green light is the most sensitive wavelength band to the human eye, perovskite materials and devices based on green light emission have garnered widespread attention in recent years, achieving notable progress. This paper provides an overview of the crystal structures and fabrication methods of perovskite materials in different dimensions from the perspectives of material synthesis and device optimization. It also summarizes various device optimization strategies for achieving high-performance green PeLEDs. Finally, the paper discusses the current challenges and future development prospects of green PeLEDs.
“In the field of near-infrared photodetectors, researchers have made significant progress. By introducing multifunctional molecules DBM, they have modulated the crystallization of Sn-Pb mixed perovskites and retarded the oxidation of Sn2+, significantly enhancing film quality. This work advances the development of Sn-Pb mixed perovskites for NIR detection and paves the way for their commercialization.”
LIU Jingjing, YANG Zhichun, BAO Haotian, MENG Xinqin, QI Minru, YANG Changgang, ZHANG Guofeng, QIN Chengbing, XIAO Liantuan, JIA Suotang
摘要:Tin-lead (Sn-Pb) mixed perovskites are extensively investigated in near-infrared (NIR) photodetectors (PDs) owing to their excellent photoelectric performance. However, achieving high-performance Sn-Pb mixed PDs remains challenging, primarily because of the rapid crystallization and the susceptibility of Sn2+ to oxidation. To address these issues, this study introduces the multifunctional molecules 2,3-difluorobenzenamine (DBM) to modulate the crystallization of Sn-Pb mixed perovskites and retard the oxidation of Sn2+, thereby significantly enhancing film quality. Compared with the pristine film, Sn-Pb mixed perovskite films modulated by DBM molecules exhibit a highly homogeneous morphology, reduced roughness and defect density. The self-powered NIR PDs fabricated with the improved films have a spectral response range from 300 nm to 1 100 nm, a peak responsivity of 0.51 A·W-1, a specific detectivity as high as 2.46 × 1011 Jones within the NIR region (780 nm to 1 100 nm), a linear dynamic range exceeding 152 dB, and ultrafast rise/fall time of 123/464 ns. Thanks to the outstanding performance of PDs, the fabricated 5 × 5 PDs array demonstrates superior imaging ability in the NIR region up to 980 nm. This work advances the development of Sn-Pb mixed perovskites for NIR detection and paves the way for their commercialization.
摘要:lanthanide ions have abundant luminescent energy levels, with their luminescence intensity and wavelength affected by the lattice symmetry. The regulation of luminescence properties via controllable lattice fields can be realized by altering electric fields and stress. Ferroelectric material has non-volatile spontaneous polarization, and its direction can be reversed or reoriented by electric fields. Doping lanthanide ions as luminescence centers into ferroelectric materials and utilizing the ferroelectric polarization field for dynamic regulation of lanthanide ions’ luminescence wavelength and intensity can significantly improve the performance of semiconductor optoelectronic devices. AlScN, with its dynamically tunable high remanent polarization, large bandgap, and high compatibility with CMOS processes, offers new opportunities for constructing novel luminescent devices with multifunctional ferroelectric regulation. This paper investigated the effects of Er3+ doping concentrations on the luminescence and ferroelectric properties of AlScN films. The Er3+ doping concentration rises, and more luminescence centers are incorporated, effectively enhancing the luminescence potential. Notably, a marked increase in luminescence of Er3+-doped AlScN films was achieved at doping concentrations of 3.6% to 9.4%. However, when the doping concentration exceeded 10%, a quenching effect led to the decrease of luminescence, highlighting the importance of precisely controlling the doping limit for optimal performance. Although the increase in Er³⁺ doping concentration slightly degraded the performance of AlScN, the remanent polarization remained above 80 μC/cm² at a concentration of 9.4%, demonstrating the coexistence of luminescence and robust ferroelectric performance in Er3+-doped AlScN films. This research fills the gap regarding lanthanide ions-doped AlScN films, laying a solid foundation for the development of highly integrated, multifunctional luminescent devices and potentially catalyzing innovation in the optoelectronic domain.
摘要:Sunlike LEDs, with their advantages of excellent spectral continuity, high color rendering index (Ra), high color fidelity (Rf), and high color saturation (Rg), have become an inevitable trend in the future of healthy lighting development. Efficient and stable multi-color phosphors are the key materials for achieving sunlike/full-spectrum LEDs. In this paper, a novel violet-excited yellow phosphor, [(Ba0.6Ca0.7Sr0.7)O2-SiO2]∶Eu2+ was synthesized using a high-temperature solid-state method based on an entropy-increasing strategy. This phosphor, under 371 nm ultraviolet excitation, emits yellow light with a spectral range of 420-800 nm and a central wavelength of 560 nm, achieving an external quantum efficiency of 75%. Notably, under 400 nm violet excitation, the luminous intensity of the phosphor can reach 88.2% of its maximum emission at the optimal excitation wavelength, achieving an external quantum efficiency of 53.0%, demonstrating good adaptability to violet chips. Finally, a sunlike LED was fabricated by combining the [(Ba0.6Ca0.7Sr0.7)O2-SiO2]∶Eu2+ yellow phosphor with commercial red, blue, and cyan phosphors and coupling with a 410 nm violet LED chip. The resulting LED exhibited high color rendering index (Ra = 96), high color saturation index (Rg = 100), and high color fidelity index (Rf = 95.1). The entropy-increasing strategy proposed in this study also provides a new approach for the development of novel high-efficiency and stable phosphor systems.
摘要:Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) have demonstrated significant application potential in the fields such as plant lighting and bioimaging. The luminescence efficiency and thermal stability of near-infrared phosphors directly determine device performance, emphasizing the importance of developing highly efficient and thermally stable near-infrared phosphors. In this study, we synthesized an efficient near-infrared phosphor, Y3InyGa5-x-yO12∶xCr3+, with a garnet structure using a high-temperature solid-state method. The emission spectrum ranges from 600 nm to 1 000 nm. By adjusting the In3+ content, we achieved spectral tuning and attained an internal quantum efficiency of up to 95.8%. Additionally, the phosphor exhibits excellent thermal stability. Experimental results show that at 423 K, the luminescence intensity remains at 83.6% of the room-temperature value. Finally, we fabricated high-efficiency NIR pc-LED devices by combining this phosphor with commercial blue LEDs, achieving a near-infrared output power of 273.5 mW under a 350 mA current drive. These results demonstrate that this series of near-infrared phosphors and NIR pc-LED devices hold high application potential.
摘要:Chiral luminescent materials have wide application prospect in the field of optics. However, the precise construction of circularly polarized luminescent materials and the elucidation of the intrinsic relationship between their supramolecular structures and circularly polarized luminescence properties remain key scientific challenges that urgently need to be addressed in the field of chiral luminescent materials. In this study, we use perylene diimide (PDI) as the model compound, to introduce chiral substituents and steric hindrance substituents into the PDI system, and then synthesize two chiral PDI derivatives (namely POSS-PDI-B6 and C10C8-PDI-B6) with gelation property. Their supramolecular structures and photophysical properties were comprehensively characterized using ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, X-ray diffraction and circularly polarized luminescence spectroscopy, respectively. The experimental results demonstrate that both POSS-PDI-B6 and C10C8-PDI-B6 are capable of forming luminescent gels. Under the synergistic effects of steric hindrance from POSS and alkyl chain substituents, as well as chiral induction from the B6 substituent, the PDI derivatives can assemble into helical supramolecular structures with chiral characteristic, thereby endowing the PDI gels with excellent circularly polarized luminescence property. These results provide valuable theoretical and experimental reference for the design and preparation of chiral optical materials.
“In the realm of aqueous zinc-ion electrochromic technology, a breakthrough has been made. Expert researchers have developed ordered WO3 nanowire films using a one-step grazing angle deposition method, which significantly enhances response speed and optical contrast during electrochromic phenomena. This advancement provides a simple and effective strategy to improve the performance of tungsten oxide-based aqueous zinc ion electrochromic materials and devices.”
CHEN Shuo, XING Kaixiao, LYU Ying, YAO Xinxin, LI Pan, GUO Xiaoyang, WANG Tienan, LI Xiaotian, LIU Xingyuan
摘要:Aqueous zinc-ion electrochromic (EC) technology, boasting the capability to fulfill both safety and cost-effectiveness requirements, is garnering extensive attention in various application areas including smart windows, thermal management, displays, and camouflage. However, typical inorganic EC materials, such as tungsten oxides (WO3), often suffer from slow ion diffusion kinetics and limited optical contrast within the aqueous Zn2+ electrolyte because of the large size and strong Coulombic interactions of the Zn2+, which limits their wide applicability. Here, ordered WO3 nanowire films, constructed by a one-step grazing angle deposition method, is demonstrated to boost the response speed and optical contrast during EC phenomena. Compared with dense films, the ordered WO3 nanowire films with a porosity of 44.6% demonstrate anti-reflective property and excellent comprehensive EC performance, including fast response time (3.6 s and 1.2 s for coloring and bleaching, respectively), large optical contrast (66.6% at 700 nm) and high coloration efficiency (64.3 cm2·C-1). A large-area prototype EC device (17 cm × 12 cm) with fast color-switching is also successfully achieved. Mechanistic studies show that the improved performance is mainly due to the ordered porous nanowire structures, which provides direct electron transfer paths and sufficient interfacial contacts, thus simultaneously enhancing the electrochemical activity and fast redox kinetics. This study provides a simple and effective strategy to improve the performance of tungsten oxide-based aqueous zinc ion EC materials and devices.
“Reporting on the latest advancements in laser crystal material research, Lutetium oxide (Lu2O3), known for its high thermal conductivity, low phonon energy, and strong crystal field, has been studied for its potential as a laser crystal material. Despite its high melting point of 2,450°C, which leads to significant temperature gradients and defect proliferation, a comprehensive understanding of its defects has been lacking. This study, using the chemical etching method, has identified optimal conditions for examining dislocation defects in Lu2O3 crystals, providing solutions to enhance crystal quality and optimize the crystal growth process. Expert research in the field of laser crystal materials has verified the optimal etching conditions for Lu2O3, laying a foundation for improving crystal quality.”
LI Guoxin, WANG Pei, MU Wenxiang, ZHAO Lili, WANG Shanpeng, YIN Yanru
摘要:Lutetium oxide (Lu2O3) is recognized as a potential laser crystal material, and it is noted for its high thermal conductivity, low phonon energy, and strong crystal field. Nevertheless, its high melting point of 2 450 ℃ induces significant temperature gradients, resulting in a proliferation of defects. The scarcity of comprehensive research on this crystal’s defects hinders the enhancement of crystal quality. In this study, we employed the chemical etching method to examine the etching effects on Lu2O3 crystals under various conditions and to identify the optimal conditions for investigating the dislocation defects of Lu2O3 crystals (mass fraction 70% H3PO4, 160 ℃, 15-18 min). The morphologies of dislocation etch pits on the (111)- and (110)-oriented Lu2O3 wafers were characterized using microscopy, scanning electron microscopy and atomic force microscopy. This research addresses the gap in understanding Lu2O3 line defects and offers guidance for optimizing the crystal growth process and improving crystal quality.
摘要:Picosecond lasers are characterized by high pulse energy, high power density, and low thermal effects, demonstrating exceptional performance in micro-machining, precision cutting, and other applications. They are widely utilized in fields such as laser processing, aerospace, and biomedical engineering. Passive Q-switching technology, which achieves pulsed laser output by modulating the Q-factor of the resonator, has become a key method for generating picosecond lasers. This paper reviews the application of passive Q-switching technology in obtaining picosecond pulses, with a focus on three distinct technical approaches: microchip structures, semiconductor saturable absorber mirrors (SESAMs) as saturable absorbers, and bonded crystals, all aimed at shortening the cavity length to achieve picosecond pulses while enhancing other performance aspects. It summarizes recent significant advancements in 1 064 nm passive Q-switching technology within picosecond pulsed laser systems and provides insights into the future development and applications of passive Q-switched picosecond lasers.
摘要:The current high-resolution quantum dot light-emitting doides(QLEDs) fabricated by various quantum dots patterning techniques suffer from low efficiency, mainly due to the passage of large leakage currents between pixels. To solve this issue, a honeycomb Poly(methyl methacrylate)(PMMA) film was fabricated by nanoimprint technique and applied as a charge barrier layer in the QLED light emitting layer. The resulting red QLEDs with a resolution of 8 467 pixel per inch(PPI) were successfully fabricated. Due to the good insulating properties of PMMA, the charge barrier layer successfully isolates the electron transport layer and the hole transport layer. Therefore, the leakage current of our device is greatly reduced compared to the device without charge barrier layer patterning, and the external quantum efficiency(EQE) is greatly improved, with a maximum EQE of 15.31% and a maximum brightness of 100 274 cd/m2.
摘要:Passive radiative cooling has garnered significant attention due to its potential in energy conservation and environmental regulation. However, the cooling power of passive radiative cooling is inherently limited by Planck’s law. Recent research found that positive photon chemical potential has the potential to enhance radiation power, albeit it necessitates an active energy input. This study proposes a theoretical model integrating a heat engine and a thermal radiation diode (TRD) that can passively achieve positive photon chemical potential, thereby enhancing radiative cooling power. The results demonstrate that the integrated system of TRD and thermoelectric generator (TEG) can effectively improve cooling power. Theoretical results indicate that the TRD-Carnot engine coupled system has the potential to achieve a peak radiation power density of 606.3 W/m² when the Carnot engine operates at 300 K (hot reservoir) and 280 K (cold reservoir). The peak radiation power density has the potential to exceed the ideal blackbody radiation density at 300 K, which is 459 W/m2. This study theoretically confirms that the synergistic effect between TRD and heat engine provides a novel approach for enhancing radiative cooling performance.
关键词:photon chemical potential;thermoradiative diodes;electroluminescence cooling;passive radiative cooling
摘要:Optical frequency comb (OFC) have great potential as an excellent multi-wavelength light source in the field of communications. The communication system can have a transmission rate in the order of a hundred Tbit·s-1 by combining the OFC light source with wavelength-division-multiplexing (WDM) and space-division-multiplexing (SDM) technologies, which is of significant application value in 5G/6G communications, Internet of Things, and autonomous driving. For an optical communication system that integrates wavelength division multiplexing and spatial division multiplexing technologies, its transmission capacity depends on the number of channels in both WDM and SDM, the modulation symbol rate of the system, and the signal-to-noise ratio (SNR) of the light source. Through an optical system based on a Brillouin laser cavity with dispersion-engineered highly nonlinear fluorotellurite fiber, we can obtain a flat OFC with a wide range of adjustable repetition frequency, spectral coverage of the entire O-U band, and a standard deviation of the comb intensity of less than 5 dB in the O-U band. This paper calculates the linewidth and frequency noise of the comb teeth across different bands of the optical frequency comb, and establishes a Brillouin optical cavityfiltering model based on the quantum Langevin equation to verify its feasibility for optical communication. The computational results indicate that the optical frequency comb in the O-U band exhibits narrow linewidths for all comb teeth, with the system’s noise low-pass filtering characteristic originating from the stimulated Brillouin cavity, and the noise power spectral density at frequencies above 1 MHz being lower than 100 Hz·Hz-1/2. Compared to external-pumped microcavity optical frequency combs, this system generates a comb with lower frequency noise in the MHz range, demonstrating that an optical system based on a Brillouin laser cavity and dispersion-engineered highly nonlinear fluorotellurite fiber can generate a low-frequency noise flat optical frequency comb in the O-U band for optical communication applications.
关键词:optical frequency comb;frequency noise;quantum Langevin equation;Brillouin optical cavity filtering model