尚蒙蒙，孙艺昕

山东大学 材料科学与工程学院，山东 济南 250061

引用格式：

尚蒙蒙，孙艺昕. Cr离子掺杂超宽带近红外发光材料的设计方法［J］.中国粉体技术，2024，30（5）：91-101.

DOI：10.13732/j.issn.1008-5548.2024.05.009

收稿日期：2024-05-17，修回日期：2024-06-27，上线日期：2024-08-12。

基金项目：国家自然科学基金项目，编号：12374376。

第一作者简介：尚蒙蒙（1987—），女，教授，博士，中国科协青年人才托举工程，山东省优青，博士生导师，研究方向为无机固体发光材料。E-mail：mmshang@sdu. edu. cn。

摘要：【目的】 近年来，由于Cr离子掺杂近红外（near-infrared， NIR）荧光材料在食品安全、医疗诊断、现代农业与环境保护等各领域的广泛应用，获得了研究人员的大量关注。NIR荧光材料的发射带宽对近红外光谱技术检测分析的灵敏度和检测范围至关重要，为获得Cr离子激活的超宽带NIR荧光材料，分析Cr离子的价态和晶格格位占据，理解发光构效关系，对实现新型Cr离子激活的超宽带NIR荧光材料具有重要意义。【研究现状】综述NIR荧光材料中Cr离子的常见价态，总结Cr离子掺杂超宽带NIR荧光材料的设计方法，概括了不同方法制备材料的发光机制，对比不同近红外荧光材料设计方法的优缺点。【结论与展望】认为选取弱晶体场环境基质材料，进行晶格位点调控是获得高效Cr离子掺杂超宽带近红外发光材料的有效方法。

关键词：Cr离子掺杂；近红外发光；发光机制

Abstract

Significance In recent years， near-infrared （NIR） fluorescent materials have gained significant attention due to their wide applications in food safety， medical diagnosis， modern agriculture， and environmental protection. The emission bandwidth of NIR fluorescent materials is crucial for the sensitivity and detection range of NIR spectroscopy. Novel NIR fluorescent materials activated by rare earth ions （Nd³⁺ 、 Dy³⁺ 、 Er³⁺ 、 Yb³⁺ ） or transition metal ions （Cr³⁺ 、 Ni²⁺ 、 Mn^2+/4+ ， and Fe³⁺ ） have been widely reported. However，trivalent rare earth ions have narrow emission bandwidths and low absorption efficiency. Although transition metal ions with d-d transitions exhibit a wider emission range， their emission half-peak width and excitation-emission wave⁃length mismatch in the NIR range are suboptimal. Cr ions are ideal NIR luminescence centers with broad absorption in the UV-visible spectrum. Understanding the valence states and lattice sites of Cr ions is essential for developing high-performance Cr ion-activated ultra-broadband NIR fluorescent materials， which are significant for NIR spectroscopy applications.

Progress This review discusses the two common valence states （+3 and +4）and three luminescent centers of Cr ions in NIR fluorescent materials： hexacoordinated Cr³⁺，tetracoordinated Cr³⁺， and tetracoordinated Cr⁴⁺. Hexacoordinated Cr³⁺ occupies octahedral lattice sites， and its luminescence varies with crystal field strength， displaying either sharp peaks or broad emissions.In spinel compounds， elements such as Mg and Al influence site occupancy， causing Cr³⁺ ions to occupy tetrahedral lattice sites， resulting in emission peaks that tend to appear at relatively longer wavelengths. Cr⁴⁺ typically emits in the 1 000~1 400 nm range， with peak wavelengths exceeding 1 200 nm. The review summarizes two design methods for Cr ion-doped ultra-broadband NIR fluorescent materials： co-doping Cr³⁺ with other ions such as rare earth （RE³⁺ ） and transition （Ni²⁺ ） ions，and selecting matrix materials with different cation lattice sites to achieve varying Cr ion valence states or having Cr ³⁺ occupy multiple lattice sites. The emission mechanisms of these methods are compared， highlighting their advantages and disadvantages. When co-doping Cr ions with RE³⁺ ions， Cr ions can act as sensitizers to broaden the infrared emission range， although this may reduce Cr ion emission intensity.

Conclusions and Prospects Selecting matrix materials with weak crystal field environments and regulating lattice sites are effective strategies for obtaining efficient Cr-doped ultra-broadband NIR fluorescent materials. By occupying different lattice sites，Cr ions can achieve a wider NIR emission range and higher concentration quenching values due to the increased total Cr ion content. These regulatory methods are also flexible， providing various ways to optimize material performance.

Keywords：Cr ion doping； near-infrared emission； luminescence mechanism

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