碳量子点及Eu3+共掺钼酸镧红色荧光粉的合成、性能及能量转移机制研究

It is a great potential solutions for white LED via using near-UV to excite red, green, and blue trichromatic phosphors to obtain white light emission. Due to the lack of the red phosphor, so it is difficult for practical application. Eu3+-doped phosphors emission spectrum are characterized by a linear emission spectrum, pure color and high luminous efficiency，while the disadvantage of them is that their excitation spectrum is also a linear spectrum in the ultraviolet area without broad excitation spectrum, so their luminescent efficiency is not high enough. Carbon dots (CDs) have a strong and broad excitation spectrum in the range of near-UV, and sensors which are composed of Eu3+ compounds observably enhanced luminescence with CDs have been applied in study for highly sensitive detection of biological molecules. Technology which emission of Eu3+ is enhanced with CDs is transferred horizontally to do studies in this project. First, different kinds of CDs will be synthesized with hydrothermal method. Then, through detailed planning of tests, CDs are tried to be codoped into Eu3+-doped lanthanum molybdates, and results to broaden and enhance the excitation spectrum of Eu3+, then the key problem problem of low light emission efficiency for Eu3+-doped red phosphors will be solved. Finally, based on understanding the best energy match between CDs and Eu3+-doped lanthanum molybdates, red phosphors of CDs,Eu3+-codoped lanthanum molybdate with significantly enhanced emission will be obtained, and energy transfer mechanism between excitation spectrum of CDs and emission spectrum of Eu3+ will be determined.

采用近紫外光激发红、绿、蓝三基色荧光粉而获得白光是一种具有发展潜力的白光LED方案，但相应的红色荧光粉比较欠缺，因而难以实际应用。Eu3+掺杂红色荧光粉的特点是具有线状发射光谱、色度较纯、流明效率较高；缺点是在紫外光区的激发光谱也是线状的，激发光谱不宽，因此发光效率不高。碳点（CDs）在近紫外段有一个强且宽大的激发光谱，用CDs显著增强发光的Eu3+化合物作为传感器已在对生物分子作高灵敏检测的研究中得到应用。本项目把该CDs增强Eu3+发光的技术横向转移过来，先用水热法合成得到不同种类的CDs，然后通过详细规划的试验，设法把CDs共掺到Eu3+掺杂钼酸镧中，拓宽并增强荧光的激发光谱，进而解决发光效率不高的关键问题。最后，弄清CDs与Eu3+掺杂钼酸镧之间的最佳能量匹配后，成得到发光明显增强的CDs,Eu3+共掺杂钼酸镧红色荧光粉，同时探明CDs激发光谱与Eu3+发射光谱之间的能量转移机理。

采用近紫外光激发红、绿、蓝三基色荧光粉而获得白光是一种具有发展潜力的白光LED方案，但相应的红色荧光粉比较欠缺，因而难以实际应用。Eu3+掺杂红色荧光粉的特点是具有线状发射光谱、色度较纯、流明效率较高；缺点是在紫外光区的激发光谱也是线状的，谱峰不宽，因此发光效率不高。碳点（CDs）在近紫外段有一个强且宽大的激发光谱，用CDs显著增强发光的Eu3+化合物作为传感器已在对生物分子作高灵敏检测的研究中得到应用。本项目把该CDs增强Eu3+发光的技术横向转移过来，设法用CDs共掺或者包覆Eu3+掺杂的荧光粉，拓宽并增强该荧光粉的激发光谱，进而解决发光效率不高的关键问题。项目已按照申请书中的研究内容和研究目标的要求顺利地完成了相应的研究工作，已成功地合成出一系列的、发光强度及热稳定性均得到明显提高的石墨烯量子点(GQDs，碳量子点中的一种)包覆的Eu3+掺杂氟化物以及GQDs包覆的Mn4+掺杂氟化物红光荧光粉。应用上，建立了获得发光强度大和发光热稳定性高之样品的合成方法。因所合成得到的红光荧光粉之发光强度及热稳定性都得到了明显的提高，所以具有很强的应用前景，为进一步的产业化转化提供了支撑。理论上，揭示了发光强度及热稳定性提高所对应的机理，而且为热稳定性的提高，创新地提出了热光能量转换的机理。相关的实验成果已经整理，相应的稿件已投到国内外的学术刊物上，共发表文章20篇。其中在SCI源的英文刊物上发表或者接收的文章17篇，含在SCI二区收录的刊物上发表文章5篇；在中文核心刊物上发表文章3篇。有多篇稿件正在投稿中。获授权及公开的发明专利各1件。本项目小组培养人才的档次得到了提高，由只能培养硕士生提升到了硕士生和博士生都能培养的档次。有9名硕士生（已毕业4人），1名博士生及2个本科生大创团队参与了项目的研究工作，并得到了相应的训练。参加国内的学术会议2次。项目总体上超额完成了考核指标的任务。