货币、身份证件、有价证券及商品的伪造和仿制严重威胁国家政治安全、金融稳定，侵害社会团体及个人利益。防伪技术是防范和抑制造假和克隆行为的有效手段，基于发光材料的防伪标签是当前防伪领域的研究热点。本文主要介绍近年来用于防伪标签的发光材料的研究进展，包括用于防伪标签发光材料的种类、防伪材料的发光机理、实现防伪鉴别所使用的激励源、发光防伪标签的设计方法及制作技术和防伪标签的鉴别方法等。此外，本文还对当前发光防伪材料存在的问题，以及未来发展趋势作了系统分析。
1 宁波大学 光电子功能材料重点实验室, 宁波 315211
2 大连海事大学 物理系, 大连 116026
采用改进的坩埚下降法成功生长了Ce 3+/Yb 3+离子双掺杂LiLuF4单晶, Ce 3+的初始离子掺杂浓度为0.1mol%, Yb 3+离子浓度从0变化到2.0mol%。在波长291 nm激发时观察到Yb 3+在1020 nm( 2F5/2→ 2F7/2)附近的强近红外发射以及Ce 3+在300~350 nm(5d→4f)的紫外发射。通过吸收光谱、荧光光谱研究了Yb 3+离子掺杂浓度对Ce 3+/Yb 3+共掺杂LiLuF4单晶光谱性质的影响及Ce 3+到Yb 3+离子的能量转移机理。通过变温光谱的研究发现, 当环境温度从298 K增加到443 K时, 其荧光发射强度不断降低。Ce 3+/Yb 3+共掺杂LiLuF4单晶发光波长主要位于紫外和近红外, 这种独特的发光属性可望用于防伪技术和公共安全事务中。
Ce
3+/Yb
3+ 紫外和近红外发射 LiLuF4单晶 能量转移 Ce
3+ and Yb
3+ ultraviolet and infrared emissions LiLuF4 single crystal energy transfer
Author Affiliations
Abstract
1 Key Laboratory of Photo-Electronic Materials, Ningbo University, Ningbo 315211, China
2 State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering and College of Physics, Jilin University, Changchun 130012, China
3 Department of Physics, Dalian Maritime University, Dalian 116026, China
Yb3+/Er3+ co-doped Na5Lu9F32 single crystals used as a spectral up-converter to improve the power conversion efficiency of perovskite solar cells are prepared via an improved Bridgman approach. Green and red up-conversion (UC) emissions under the excitation of near-infrared (NIR) bands of 900–1000 nm and 1400–1600 nm can be observed. The effectiveness of the prepared materials as a spectral converter is verified by the enhancement of power conversion efficiency of perovskite solar cells. The sample with a UC layer is 15.5% more efficient in converting sunlight to electricity compared to the UC layer-free sample due to the absorption of sunlight in the NIR range. The results suggest the synthesized Yb3+/Er3+ co-doped Na5Lu9F32 single crystals are suitable for enhancing the performance of perovskite solar cells.
160.4670 Optical materials 260.1180 Crystal optics 260.2510 Fluorescence 350.6050 Solar energy Chinese Optics Letters
2019, 17(9): 091601
Author Affiliations
Abstract
1 Key Laboratory of Photo-Electronic Materials, Ningbo University, Ningbo 315211, China
2 College of Physics and Electronic Engineering, College of Chemistry and Pharmaceutical Engineering, Nanyang Normal University, Nanyang 473061, China
3 Department of Physics, Dalian Maritime University, Dalian 116026, China
A 0.1 mol.% CoF2-doped Na5Lu9F32 single crystal with high quality in the size of ～ 10 mm×100 mm was grown by the Bridgman method. Three peaks located at 504, 544, and 688 nm and a broad band in the range of 1200–1600 nm centered at 1472 nm were observed in the absorption spectra. The absorption peak position suggests cobalt ions in the divalent state in the grown crystal. Moreover, the cobalt ions are confirmed to locate in the distorted cubic crystal structure. Upon excitation of 500 nm light, a sharp emission peak at 747 nm ascribed to the T22(H1)→4A2(F) transition was observed for the crystal. The Co2+-doped Na5Lu9F32 crystal shows a potentially promising material for the application of a passively Q-switched laser operating in the near-infrared range.
160.4670 Optical materials 140.3380 Laser materials Chinese Optics Letters
2018, 16(6): 061601
Author Affiliations
Abstract
1 Key Laboratory of Photoelectronic Materials, Ningbo University, Ningbo 315211, China
2 Ningbo Institute of Materials Technology and Engineering, the Chinese Academy of Sciences, Ningbo 315211, China
3 Department of Physics, Dalian Maritime University, Dalian 116026, China
A Ce3+ ion-doped α-NaYF4 single crystal of high quality is grown successfully by an improved flux Bridgman method under the conditions of taking the chemical raw composition of NaF:KF:YF3:CeF3 in the molar ratio of 30∶18∶48∶4, where the KF is shown to be an effective assistant flux. The x ray diffraction, absorption spectra, excitation spectra, and emission spectra of the Ce3+-doped α-NaYF4 single crystal are measured to investigate the phase and optical properties of the single crystals. The absorption spectrum of the Ce3+:α-NaYF4 shows a strong band that peaks at the wavelength of 300 nm. The emission spectrum of the Ce3+:α-NaYF4 emits an intense ultraviolet (UV) band at the wavelength of 332 nm under the excitation of 300 nm light. Two separated luminous bands of 330 and 350 nm, which correspond to the transitions 5d→F5/22 and 5<
160.0160 Materials 230.0230 Optical devices 260.1180 Crystal optics 300.0300 Spectroscopy Chinese Optics Letters
2016, 14(6): 061601
Author Affiliations
Abstract
1 Key Laboratory of Photo-Electronic Materials, Ningbo University, Ningbo 315211, China
2 Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315211, China
3 Department of Physics, Dalian Maritime University, Dalian 116026, China
The absorption spectra, excitation spectra, and emission spectra of
Tb3+/Eu3+ ions in
LiYF4 single crystals synthesized by an improved Bridgman method are measured. The emission spectra of several bands, mainly located at blue
～487 nm (
Tb:D45→F76), yellowish green
～542 nm (
Tb:D45→F75), and red
～611 nm (
Eu:D05→F72) wavelengths, are observed under excitation by UV light. An ideal white light emission as a result of simultaneous combination of these emissions can be obtained from 1.11 mol%
160.0160 Materials 230.0230 Optical devices 300.0300 Spectroscopy Chinese Optics Letters
2015, 13(7): 071601
