IEEE JOURNAL OF QUANTUM ELECTRONICS
·
2020
·Vol. 56
·期 3
·1-9
·
IF 2.384
Zong-Tao Li,Jie-Xin Li,Jia-Sheng Li,Zi-Hao Deng,Yue-Hua Deng,Yong Tang
The scattering effect plays an important role in improving the optical performance of the quantum dot (QD) white light-emitting diodes (LEDs). A majority of the previous studies have focused on the planar packaging structure only with respect to total internal reflection (TIR). In this study, SiO2 nanoparticles are incorporated into QD-silicone encapsulation of LEDs with semi-spherical lens packaging (SSLP) to exploit their scattering effect. The results show that the radiant efficacy (31.35%@100 mA) and luminous efficacy (87.56 lm/W@100 mA) of QD white LEDs can be optimized using SiO2 nanoparticle concentration (0.1 wt%) and that they increase by 5.04% and 11.08%, respectively, as compared to the conventional structure. A comprehensive ray-tracing simulation validates that the nanoparticles in the SSLP structure lead to severe loss of chip light. On the contrary, the fluorescence light increases due to the enhancement of conversion by QDs. The transmission electron microscopy images and the finite-difference time-domain simulation have been introduced to investigate the surface adsorption of SiO2 nanoparticle. This study indicates that SiO2 incorporation is an effective method to improve the efficiency of QD white LEDs, and provides a better understanding on the scattering effect based on TIR, color conversion, and surface adsorption.
研究领域:
光学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Haiyang Du,Haipeng Yu,Daniel K. Macharia,Haiyan Zeng,Haifeng Wang,Ran Cao,Nuo Yu,Meifang Zhu,Zhigang Chen
High-energy ionizing radiation brings serious challenges to medical professionals, and it demands efficient and lightweight shielding materials depending on high-Z elements and structural supporting matrices. Herein, we have integrated multiple high-Z elements and multilayer structures into composite films with interlayer scattering effects for constructing high-energy X-ray shielding clothes. A series of composite films containing different combinations of X-ray shielding particles (SnO 2 , BaSO 4 , and Bi 2 O 3 ) were prepared in tightly connected two layers with each layer consisting of corresponding hybrid polyacrylonitrile (PAN) fibers-reinforced hybrid thermoplastic polyurethane (TPU) coating. The optimized composite film L Ba3.7 /L Bi3.7 avoids lead toxicity and has a tensile strength of 17.92 MPa and high flexibility due to the reinforcing effect of PAN hybrid fibers. The L Ba3.7 /L Bi3.7 with a density of ∼ 2.98 g cm −3 and a thickness of 2.24 mm exhibits 18 % lighter than the 0.5 mmPb lead apron. Owing to the combination of multiple particles and layer structures, the absorption and interlayer scattering effects of L Ba3.7 /L Bi3.7 are leveraged to confer a high X-ray shielding efficiency of 96.3 % at 100 keV, surpassing single-element films and closing to 0.5 mmPb lead apron. This work offers a viable strategy for developing flexible, lightweight, and efficient wearable materials for high-energy X-ray shielding.
研究领域:
材料科学
·
医学防护
·
辐射防护
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2024
·
IF 6.3
Chuanxin Yang,Ronghui Han,Xiaoyu Guo,Shufen Zhang,Bingtao Tang,Yuang Zhang
Passive radiative cooling technology has received extensive attention as an environmentally friendly cooling solution. However, existing radiative coolers often suffer from complexities in preparation and high costs, limiting their practical applications. Here, a novel porous structure with randomly distributed microspheres is fabricated in a low-cost and simple method known as solvent volatilization-induced phase separation, employing polyvinylidene fluoride (PVDF) and monodispersed SiO 2 microspheres. Utilizing the regulation of parameters such as the size of the pores and microspheres, controllable multi-scattering of light by the microstructures is achieved. The porous PVDF/SiO 2 film, with an average solar reflectance of 93.8% and an average atmospheric window emissivity of 0.958, is self-supporting and exhibits excellent flexibility and mechanical strength. When applied to closed and windowed models, the porous PVDF/SiO 2 film effectively lowers the internal temperatures by an average of 7.0 °C and 4.6 °C in summer, respectively, and by an average of 6.7 °C and 4.4 °C in spring. This work provides a viable strategy for achieving efficient radiative cooling and improving building energy management in a simple, cost-effective, and scalable manner.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED POWDER TECHNOLOGY
·
2015
·
IF 2.638
Yuan-Yuan Yu,Bing-Xin Lei,Min-Li Xie,Guo-Lei Huang,Wei Sun,Zhen-Fan Sun
Core–shell TiO 2 (cs-TiO 2 ) hollow microspheres are prepared via a facile hydrothermal method, by using titanium potassium oxalate precursor in dilute sulfuric acid. The characterization shows that the as-prepared TiO 2 microspheres have core–shell structure. The diameters of cs-TiO 2 microspheres are in the range of 2–5 μm. The optical investigation evidences that the cs-TiO 2 microsphere film exhibits a prominent light-scattering effect at a wavelength range of 600–800 nm. The cs-TiO 2 microspheres are applied as a scattering layer on top of a nanocrystalline P25 film, serving as the photoanode of dye-sensitized solar cells (DSSCs). A high efficiency of 7.7% is achieved after introducing the cs-TiO 2 hollow microsphere scattering layer, compared with 6.21% for the photoanode with commercial P25. Based on the optical investigation and electrochemical impedance measurement, the improved efficiency can be ascribed to the enhanced light-scattering ability and the reduced interface recombination rate.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
Materials Horizons
·
2025
·
IF 10.7
Yujie Peng,Peipei Shao,Ye Yuan,Jingru Mou,Ruitao Wen,Hong Chen,Ming Xiao
Traditional thermochromic materials prioritize high sensitivity and rapid discoloration. Reversible thermochromism with delayed discoloration is highly desirable for applications like thermal history indicators and energy-saving windows, yet it has rarely been achieved. Here, we construct such thermochromic composites simply by assembling hydrophobic silica nanoparticles in a polydimethylsiloxane (PDMS) matrix. The films transition from colorless and translucent to blue within minutes when heated above 60 °C and retain their blue color for over eight hours at 20 °C. Remarkably, the discoloration time can be further extended by lowering the environmental relative humidity. Integrating measurements of water absorption, refractive indices, and optical model calculation, we demonstrate the coloration rises from the combined effects of Rayleigh scattering and multiple scattering and the prolonged discoloration time is suprisingly caused by the gradual absorption of moisture. This unique thermochromic material opens new avenues for advancing thermochromic technology applications.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Xiaolu Liang,Zihao Chen,Zhenyu Wang,Zimeng Pan,Yao Wang,Haitao Wang,Jiankun Sun,Jun Ma,Xuexing Jiang,Jubo Peng,Xin Gu,Jing Zhang,Xiang Liu
Polycrystalline La 0.815 Sr 0.185 MnO 3 (LSMO) ceramic was synthesized using the sol-gel method. The effect of varying sintering temperatures (1763, 1783, 1803 and 1823 K) on the microstructure and electrical transport properties were systematically investigated. The samples exhibited a distinct dual-peak metal-insulator transition, with the first peak ( T p1 ) primarily influenced by grain boundary (GB) scattering effect. At lower sintering temperatures, lattice strain induced by the ionic size mismatch between La 3+ and Sr 2+ ions is transferred to the grain boundaries, increasing their contribution to resistivity. As the sintering temperature rises, the grain boundary effect diminish, leading to a suppression of the T p1 peak. Elevated sintering temperatures further promote hybridization effect, enhancing the double exchange mechanism. As the temperature increases, this mechanism gradually becomes dominant, leading to a more pronounced influence of the T p2 peak. Additionally, higher sintering temperatures reduce grain boundary scattering, improving the temperature coefficient of resistivity ( TCR ). At an optimal sintering temperature of 1803 K, the LSMO ceramic achieved a peak TCR of 10.78% K -1 near room temperature (284.8 K), demonstrating strong potential for improved performance in uncooled infrared bolometers or electronic switch devices.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2024
·
IF 3.3
Chenyini Xu,Meng Chen,Shu Xu,Chong Geng
Optical scatterer additives play a critical role in enhancing the light conversion efficiency and uniformity of quantum dot-converted light-emitting diodes (Qc-LEDs). This study investigates the impact of optical characteristics and morphology of nanoscatterer on the light conversion and extraction efficiency of Qc-LEDs. Various metal oxides and boron nitride nanoparticles and nanoplates with different diffraction index were selected to carry out the study. Finite-Difference Time-Domain (FDTD) simulation was employed to evaluate the scattering effect of various nanosphere and nanoplate scatterers on the optical performance of the Qc-LEDs. The simulation results revealed that the hybrid nanoscatterer integrates the forward-scattering from the nanosphere and backward-scattering of blue light from the nanoplate. Spectral analysis was conducted to examine the optical performance of Qc-LEDs with varying combinations and concentrations of nanoscatterers. TiO 2 nanoparticles and Al 2 O 3 nanoplates were found to be the best combination for maximal light conversion and extraction efficiency within Qc-LEDs. The results indicate an optimal light efficiency is obtained with the optimal ratio of 1:2:2 for quantum dots, TiO 2 nanoparticles, and Al 2 O 3 nanoplates. These findings reveal the relationship between optical properties, morphology, and light conversion efficiency in Qc-LEDs, highlighting the advantages of the hybrid nanoscatterers for improving optical performance of Qc-LEDs.
研究领域:
光学
·
材料科学
·
纳米技术
·
光子学
·
半导体器件
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）