OPTICAL MATERIALS
·
2022
·
IF 3.754
Zhong Wan,Ge Zhang,Benxue Jiang,Tao Feng,Long Zhang,Xiao Li
As a prospective alternative technique for single crystal growth , solid-state crystal growth (SSCG) is applied in the fabrication of a Nd:YAG/YAG composite structure with a high Nd 3+ doping concentration. The microstructure morphologies and segregation behavior in the ceramic matrix, growth interface, and grown crystal are investigated. The results indicate that the dopant ions diffuse along with the grain boundary migration during the SSCG process while the segregation coefficient at the growth interface is higher than that of the grain boundary. A homogeneous grown crystal without segregation generates in a 6 at.% doping sample. When the doping concentration exceeds the solubility limit of the crystal lattice , surface morphology defects emerge as numerous protuberances in an 8 at.% doping sample. The SSCG technique has bright application prospects in heavily doped YAG crystal, especially for active ion diffusion limitation during the fabrication of planar waveguides .
研究领域:
材料科学
·
晶体生长
·
光学材料
·
固体物理
·
光子学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry Letters
·
2019
·
IF 7.329
Xiangtong Zhang,Hua Wang,Yue Hu,Yixian Pei,Shixun Wang,Zhifeng Shi,Vicki L. Colvin,Shengnian Wang,Yu Zhang,William W. Yu
Colloidal lead halide perovskite nanocrystals (NCs) have high tunability in the visible light region and high photoluminescence quantum yields (PL QYs) for green and red emissions, but bright blue emission is still a challenge. Super small CsPbBr3 perovskite NCs emit blue light around 460 nm with a narrow peak width, and they do not have the problem of phase separation like their Cl–Br counterparts. However, the blue emission from super small CsPbBr3 NCs easily becomes green over time, and their PL QY is still low. The doping of Sb3+ ions successfully reduced the surface energy, improved the lattice energy, passivated the defect states below the band gap, eventually boosted the PL QY of blue emission to 73.8%, and resulted in better spectral stability even at elevated temperatures in solution (40–100 °C). Its CIE coordinates were (0.14, 0.06), which are close to the primary blue color (0.155, 0.070) according to the NTSC TV color standard.
研究领域:
材料科学
·
纳米技术
·
光电子学
·
光子学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Guixian Li,Gan Li,Qinan Mao,Lang Pei,Hua Yu,Meijiao Liu,Liang Chu,Jiasong Zhong
Mn 4+ -activated phosphors are of great interest in luminescence lifetime thermometry due to the luxuriant luminescence properties influenced by the locally surrounding crystal field. It is highly desirable to develop effective Mn 4+ -based luminescence lifetime thermometry through modulating the structural parameters. In this work, by introducing the smaller Mg 2+ ions to replace Ca 2+ site in the BaLaCaSbO 6 matrix, a 4.2-fold enhance in the luminescence intensity, red-shifted from 690 nm to 698 nm, as well as luminescence lifetime increase from 0.212 to 0.951 ms is achieved. These modulations are mainly attributed to the strengthen pressure on the local structure, superior lattice rigidity and suppresses non-radiative transition after the substitution of smaller Mg 2+ . Interestingly, owing to the obvious thermal quenching behavior of Mn 4+ ions in the matrix, effective lifetime-based luminescence thermometry can be realized. Mg 2+ dopant results in the improvement of the absolute sensitivity from 1.22 µsK −1 (BaLaCaSbO 6 :Mn 4+ @408 K) to 4.88 µsK −1 (BaLaCa 0.1 Mg 0.9 SbO 6 :Mn 4+ @401 K).
研究领域:
材料科学
·
发光材料
·
光学测温
·
固态化学
·
光子学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Qianrui Ma,Ting Wang,Wei Gao,Bitao Liu,Hao Zhang,Zhenzhen Cui,Haihong Guo,Liang Xiu,Shaoqing Wang,Ziyang Li,Longchao Guo,Siufung Yu,Xue Yu,Xuhui Xu,Jianbei Qiu
Wearable biosensing and food safety inspection devices with high thermal stability, high brightness, and broad near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) could accelerate the next-generation NIR light applications. In this work, NIR La3–xGdxGa5GeO14:Cr3+ (x = 0 to 1.5) phosphors were successfully fabricated by a high-temperature solid-state method. Here, by doping Gd3+ ions into the La3+ sites in the La3Ga5GeO14 matrix, a 7.9-fold increase in the photoluminescence (PL) intensity of the Cr3+ ions, as well as a remarkably broadened full width at half-maximum (FWHM) of the corresponding PL spectra, is achieved. The enhancements in the PL, PLE intensity, and FWHM are attributed to the suppression of the nonradiative transition process of Cr3+ when Gd3+ ions are doped into the host, which can be demonstrated by the decay curves. Moreover, the La1.5Gd1.5Ga5GeO14:Cr3+ phosphor displays an abnormally negative thermal phenomenon that the integral PL intensity reaches 131% of the initial intensity when the ambient temperature increases to 160 °C. Finally, the broadband NIR pc-LED was fabricated based on the as-explored La1.5Gd1.5Ga5GeO14:Cr3+ phosphors combined with a 460 nm chip, and the potential applications for the broadband NIR pc-LEDs were discussed in detail.
研究领域:
材料科学
·
光学材料
·
光子学
·
固态化学
·
发光材料
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Yi Zhang,Yanjie Liang,Xihui Shan,Dongxun Chen,Shihai Miao,Ruiqi Shi,Fei Xie,Weili Wang
Persistent phosphors emitting in the narrowband ultraviolet-B (NB-UVB) spectral region have aroused significant interest, owing to their special self-illuminating feature in realizing many advanced technological applications under excitation-free conditions, such as dermatological therapy and invisible optical tagging. Here, we focus our discussion on a new Gd3+-doped persistent phosphor, Sr2P2O7:Gd3+, which exhibits long-lasting NB-UVB persistent luminescence peaking at 312 nm for more than 24 h after charging by an X-ray beam. The NB-UVB light emission from the charged Sr2P2O7:Gd3+ phosphor can be clearly detected by a UVB camera in bright indoor environment. More importantly, the enhancement of NB-UVB afterglow intensity and decay time can be observed under continuous photostimulation of polychromic indoor ambient light. Furthermore, applying charged Sr2P2O7:Gd3+ phosphors as invisible optical taggants, clear and interference-free recognition of the encrypted message and location of different objects have been realized due to the lack of UVB light in bright indoor environment. The as-prepared Sr2P2O7:Gd3+ persistent phosphor is expected to offer new directional solutions for the development and application of ultraviolet luminescence technology.
研究领域:
材料科学
·
发光材料
·
光学工程
·
光子学
·
生物医学应用
✓ 已验证
DOI
高影响因子
POLYMER
·
2020
·
IF 4.231
Tiantian Guo,Yi Wang,Yaping Qiao,Xiaoyan Yuan,Yunhui Zhao,Lixia Ren
One-dimensional photonic crystals (1D PCs) prepared by solvent annealing self-assembly of bottlebrush block copolymers have attracted much attention due to their low cost and convenient preparation. However, such 1D PCs are usually unstable as the reflectance will red shift at high temperature. Herein, we study the thermal stability of 1D PCs by post-thermal self-assembly. In general, the 1D PCs with lamellar structures are prepared by solvent annealing self-assembly of bottlebrush block copolymers with hard main chain, polystyrene- block -poly( tert -butyl acrylate) (H(PS- b -P t BA)). At temperatures higher than the glass transition temperature of side chains and main chain, the 1D PCs start to post self-assembly, which reaches equilibrium state when treated at high temperature for 8 h. Correspondingly, the reflectance of the 1D PCs red shifts from purple to blue gradually with temperature increase. Scanning electron microscope characterization shows that after thermal treatment, the domain spacing of the lamellar phases is increased from 108 nm to 160 nm, which results in the red shift of the reflectance wavelength. The red shift of the 1D PCs is related to the metastable self-assembly of bottlebrush block copolymers, which will further self-assemble at high temperatures to increase the domain spacing. After reaching equilibrium, the 1D PCs are thermal stable, which shows potential in high temperature resistance.
研究领域:
材料科学
·
聚合物化学
·
光子学
·
纳米技术
·
热性能
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Zheqin Liu,Yongqiang Zhang,Yi Fan,Zhenqiang Chen,Zhaobing Tang,Jialong Zhao,Ying lv,Jie Lin,Xiaoyang Guo,Jiahua Zhang,Xingyuan Liu
Methylammonium (MA) lead halide (MAPbX3, X = Cl, Br, I) perovskite quantum dots (PQDs) are very sensitive to environment (moisture, oxygen, and temperature), suffering from poor stability. To improve the stability, we synthesized silica-coated PQDs (SPQDs) by an improved ligand-assisted reprecipitation method through simply mixing and stirring under room temperature in air without adding water and catalyst, the whole process took only a few seconds. The photoluminescence (PL) spectra of the SPQDs can be tuned continuously from 460 to 662 nm via adjusting the composition proportion of precursors. The highest PL quantum yields (PLQYs) of blue-, green-, and red-emissive SPQDs are 56, 95, and 70%, respectively. The SPQDs show remarkably improved environmental and thermal stability compared to the naked PQDs because of effective barrier created by the coated silica between the core materials and the ambience. Furthermore, it is found that different light-emitting SPQDs can maintain their original PL properties after mixing of them and anion-exchange reactions have not happened. These attributes were then used to mix green- and yellow-emissive SPQDs with polystyrene (PS) to form color-converting layers for the fabrication of white light-emitting devices (WLEDs). The WLEDs exhibit excellent white light characteristics with CIE 1931 color coordinates of (0.31, 0.34) and color rendering index (CRI) of 85, demonstrating promising applications of SPQDs in lighting and displays.
研究领域:
材料科学
·
纳米技术
·
光电子学
·
光子学
·
照明与显示
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Donghui Kou,Wei Ma,Shufen Zhang,Jodie L. Lutkenhaus,Bingtao Tang
Colorimetric sensors, as a key branch of the application of photonic crystals (PCs), brings enthusiasm to scientists to do research. Here, simple mesoporous and structurally colored one-dimensional photonic crystals (1DPCs) constructed by alternating assembly of poly(acrylamide-N,N′-methylene bis(acrylamide)) (P(AM-MBA)) nanogels and TiO2 nanoparticles are reported as high-performance colorimetric humidity sensors. The sensors with bright colors display rapid response to relative humidity (RH) change and reach sensing balance in 0.5 s. By varying RH from 47.0% to 89.3%, stopband of a sensor changes from 426 to 668 nm, almost spanning the whole visible range. Meanwhile, visual sensing of RH possesses good reversibility and repeatability. Moreover, the sensors with delicate patterns are facilely fabricated by partial UV photodegradation of the polymer layers with nano TiO2 as catalyst. The delicate patterns and backgrounds show different colors and change color simultaneously and quickly by varying the ambient humidity. Accurate QR code pattern is also realized on the PC sensor; it is found successful reading of the data is only achieved by increasing RH to realize high color contrast between the code and background. Given their excellent properties, the porous hybrid PCs are promising as high-performance humidity sensors with potential display, decoration, information-storage, and encryption functions.
研究领域:
材料科学
·
传感器与检测技术
·
光子学
·
纳米技术
·
智能材料
·
环境监测
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2018
·
IF 4.7
Hao Lin,Dekang Xu,Yongjin Li,Lu Yao,Liqin Xu,Ying Ma,Shenghong Yang,Yueli Zhang
Luminescence efficiency of trivalent lanthanide-doped upconversion (UC) materials is significantly limited by luminescence concentration quenching. In this work, red UC emission is dramatically enhanced in Er3+-sensitized NaLuF4 UC crystals through energy trapping under multiple excitation wavelengths. Cross-relaxation quenching and the energy migration to internal lattice defects are simultaneously suppressed by confining the excitation energy in the Er3+ activator after introducing the Tm3+ or Ho3+ energy trapping center. The enhanced red UC emission (Er3+: 660 nm) mainly comes from the effective excitation energy confinement by Tm3+ and Ho3+ trapping centers through an easy energy transfer between Er3+ and Tm3+/Ho3+: 4I11/2 (Er3+) → 3H5 (Tm3+) → 4I13/2 (Er3+) and 4I11/2 (Er3+) → 5I6 (Ho3+) → 4I13/2 (Er3+). It is found that the confining efficiency of excitation energy in Er3+-sensitized NaLuF4 crystals is higher than that in Yb3+/Er3+ cosensitized NaLuF4 crystals, and the luminescence efficiency of Er3+-sensitized NaLuF4 crystals is much higher than that of Er3+-based host sensitization UC crystals (NaErF4). Moreover, Er3+-sensitized UC particles can be efficiently excited by three different wavelengths (808, 980, and 1532 nm), indicating huge advantages for applications in bioimaging, anticounterfeiting, and solar cells.
研究领域:
材料科学
·
光子学
·
发光材料
·
光学工程
·
纳米技术
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2016
·
IF 4.509
Changgui Lin,Legang Li,Shixun Dai,Chao Liu,Zhiyong Zhao,Christian Bocker,Christian Rüssel
Nickel ion doped transparent bulk glass-ceramics containing K2SiF6, ZnF2, and KZnF3 nanocrystals were elaborated to show the prospect that this novel group of oxyfluoride glass-ceramics is promising for transition metal ion based photonics. These new oxyfluoride glass-ceramics exhibit a new broadband luminescence of Ni2+ ions in the intriguing near-IR spectral region ranging from 1200 to 2400 nm. Ni2+ ions are incorporated into the precipitated K2SiF6, ZnF2, and KZnF3 crystals, which provide octahedral sites for Ni2+ and make it optically active. Taking into account the microstructure of phase separation observed by replica TEM, a detailed mechanism of phase-separation-assisted nanocrystallization was described for these oxyfluoride glasses. These results allow one to establish a full physical model of the nanocrystallization mechanism. For the precipitation of fluoride crystallites, not only can the nanometric size be explained but also the formation of different crystal phases can be controlled by the initial amorphous phase separation of droplet or interpenetrating structure with a sufficiently elaborated glass design.
研究领域:
材料科学
·
光子学
·
固态化学
·
纳米材料
·
光学材料
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Zhenyao Bian,Zi Wang,Hongbo Lu,Miao Xu
Nonmechanical fast response optical beam steering technology is increasingly essential for telecommunications, imaging systems, optical sensing, displays, and military applications. Polymer network liquid crystal (PNLC) beam steering can achieve submillisecond response times but faces limitations due to scattering issues arising from the refractive index mismatch between the polymer network and the liquid crystals (LCs). In this article, we demonstrate a scattering-free, fast-response LC beam steering by using polymer brushes to stabilize the gradient refractive index. First, the initiator is incorporated into the alignment layer and the monomer is mixed into the LC layer. Surface-initiated polymerization (SIP) is then employed to grow the polymer brushes exclusively on the substrate’s surface, thus confining the polymer network’s growth to the LC bulk and reducing interfacial scattering. For polymer brush stabilized liquid crystal (PBSLC) beam steering device with a period size of 225 μm and a cell gap of 7.2 μm, the average transmission rate reaches 88% in the visible light spectrum with a haze value of only 6.91. The steering angle is 0.16, and the diffraction efficiency is 80.3%. When a voltage of 35 Vrms is applied, the primary energy can be tuned to the zeroth order, with a response time close to 1 ms. By cascading two PBSLC beam steering devices with opposite steering directions, the primary energy of the beam can be adjusted between zeroth, +1, and −1 order. This method requires only a UV light source, a precision displacement stage, a power supply, and a mask, avoiding the need for expensive equipment and complex electrode fabrication. By adjustment of the phase change period, step width, and number of steps during fabrication, the steering angles and diffraction efficiency of the PBSLC beam steering device can be easily controlled, highlighting its significant potential for industrial production.
研究领域:
光学
·
光子学
·
材料科学
·
液晶技术
·
非机械式光束偏转
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2021
·
IF 5.165
Yufeng Zhou,Yanxia Yu,Yaqian Zhang,Xiaodong Liu,Haisheng Yang,Xiaojuan Liang,Wei Xia,Weidong Xiang
All-inorganic halide perovskite (CsPb2Br5) nanocrystals (NCs) have received widespread attention owing to their unique photoelectric properties. This work reports a novel strategy to control the phase transition from CsPbBr3 to CsPb2Br5 and investigates the effects of different treatment times and treatment temperatures on perovskite NCs formation. By controlling the volume of tetraethoxysilane (TEOS) added, the formation of different phases of perovskite powder can be well controlled. In addition, a white light-emitting diode (WLED) device is designed by coupling the CsPbBr3/CsPbBr3–CsPb2Br5 NCs@TEOS nanocomposite and CaAlSiN3:Eu2+ commercial phosphor with a 460 nm InGaN blue chip, exhibiting a high luminous efficiency of 57.65 lm/W, color rendering index (CRI) of 91, and a low CCT of 5334 K. The CIE chromaticity coordinates are (0.3363, 0.3419). This work provides a new strategy for the synthesis of CsPbBr3/CsPbBr3–CsPb2Br5 NCs@TEOS nanocomposite, which can be applied to the field of WLEDs and display devices.
研究领域:
材料科学
·
光电子学
·
纳米技术
·
发光二极管（LED）
·
光子学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）