宽谱激发无机-有机杂化纳米材料的制备、发光性能调控及应用研究

In recent years, lanthanide-doped inorganic-organic hybrid nanomaterials have received intensive attention from researchers across the world. Their outstanding photoluminescence is a result of the efficient energy transfer (or the “antenna” effect) from the organic ligands to the lanthanide ions. Recent research indicated that the inorganic-organic hybrid nanomaterials can possess remarkable double-channel excitation characteristics after a controlled annealing process. These two excitation channels can have different intensity and spectral range, which can be used to tune their photoluminescence properties. Taking advantage of such double-channel excitation characteristics for the inorganic-organic hybrid nanomaterials, this project will optimize the two excitation channels by adjusting the preparation and post-processing conditions. Consequently, the excitation spectral bandwidth of the inorganic-organic hybrid nanomaterials is greatly widened, and their photoluminescence is optimized in a controlled manner. In order to investigate the dynamic effects of the two excitation channels when simultaneously initiated on the photoluminescence properties of the inorganic-organic hybrid nanomaterials, a novel experimental method was proposed. Two optical sources will be used in this method so that the two excitation channels can be simultaneously initiated. The dynamic interaction mechanism between the two excitation channels can therefore be systematically studied. The applications of the inorganic-organic hybrid nanomaterials in the spectral conversion for solar cells and the imaging of cells are to be explored. The research results of this project will be experimentally and theoretically beneficial to the development of inorganic-organic hybrid nanomaterials with wide excitation spectral bandwidth.

稀土掺杂无机–有机杂化纳米材料在近年来受到国内外研究人员的极大关注，其优异的发光性能来自于有机配体向稀土离子的高效率能量传递（或“天线”效应）。近期研究表明这种无机–有机杂化纳米材料经过特定热处理后能够显示出较显著的双重激发特性，这两种激发模式可以体现出不同的强度和谱段范围，是实现对其发光性能调控的技术基础。本项目将基于无机–有机杂化纳米材料的这种双重激发特性，通过可控制备和后处理工艺对这两种激发模式进行调控，达到宽谱激发的研究目标及其发光性能的全面调控。为了研究这两种激发模式在同时被启动状态下对发光性能的动态影响行为，我们创新性地提出了在双光源激发模式下研究其发光性能的实验方案，对这两种激发模式之间的动态相互作用机制进行系统性研究。本项目也将对这种宽谱激发杂化纳米材料在太阳电池光谱转换和细胞成像技术领域的应用进行深入探索。本项目研究结果将为研制宽谱激发纳米发光材料提供实验和理论基础。

稀土离子的窄谱吸收常导致稀土掺杂发光材料具有较窄的激发谱，这极大地限制了这些材料的应用范围。通过引入多种宽谱激发机制并进行调控，实现了稀土掺杂发光材料的宽谱激发特性，其激发谱可覆盖太阳光紫外光谱。采用溶剂热法合成了LaF3:Eu3+和YVO4:Eu3+@YVO4:Eu3+纳米发光材料。通过复合型无机-有机杂化技术将苯甲酸（BA）和噻吩甲酰三氟丙酮（TTA）两种有机配体与LaF3:Eu3+形成LaF3: Eu3+–BA–TTA无机-有机杂化纳米发光材料，BA和TTA两者宽激发谱的叠加使LaF3:Eu3+–BA–TTA的紫外激发谱宽从10 nm显著扩展到200 nm，实现其紫外宽谱激发（波长范围200 ~ 400 nm）的特性，覆盖太阳光紫外谱段，将紫外光高效地转变成可见光，使晶体硅太阳能电池的转换效率提高了0.7%的绝对值，有较强的应用前景。与TTA杂化得到的YVO4:Eu3+@YVO4:Eu3+–TTA无机-有机杂化纳米发光材料，通过VO43-→Eu3+激发和TTA敏化两种宽谱激发机制的调制使其激发谱显著宽化（波长范围230 ~ 415 nm），实现了其紫外宽谱激发特性。较系统地研究了Ce3+/Tb3+/Eu3+共掺β-NaYF4中Ce3+→(Tb3+)n→Eu3+的能量传递过程，通过Tb3+的桥梁作用实现了Ce3+到Eu3+的能量传递，宽化了其激发谱。对溶剂热法合成β-NaYF4:Eu3+过程中表面活性剂和溶剂比例对其微观形貌和发光性能的影响规律进行了研究，并对其内在机制进行了探索。对Ba2+掺杂的YVO4:Eu3+发光材料，Ba2+掺杂既提高了其发光性能又使其激发峰蓝移，通过对其荧光寿命分析和第一性原理计算系统地研究了Ba2+掺杂对其发光性能的影响机制。Ba2+掺杂延长了YVO4:Eu3+的荧光寿命，增大了YVO4:Eu3+的禁带宽度，这导致其激发峰蓝移，同时Ba2+掺杂导致Eu3+的Eu-d轨道分裂，使Eu3+的5D0→7F2发射峰宽化。Ba2+掺杂使Y-d和V-d轨道态移向了更高的能量位置，而Eu-d轨道态则几乎不变，这增大了VO43-→Eu3+能量传递效率，从而提高其发光性能。研究了抑癌基因p53下游调控因子PHLDA3在体细胞重编程过程中的功能以及环形RNA分子CircACC1调控细胞代谢的信号通路，获得了较有参考价值的结果，为后续研究提供了基础。