TiO2纳米胶囊包覆的三重态湮灭上转换发光材料的研究

Triplet-triplet annihilation photon upconversion materials coated with TiO nanocapsules

三重态-三重态湮灭(triplet-triplet-annihilation, TTA)上转换,是一种能够实现低能量光波向高能量光波转换的技术,该体系主要由三重态敏化剂和能量受体两部分组成,此类机制的上转换主要在溶液中发生,很难作为一个分子整体使用,这将大大限制其应用领域.本文通过使用胶束软模板法将敏化剂和能量受体包覆到二氧化钛(TiO2)壳内,成功制备了基于TTA上转换的高效上转换纳米胶囊(TTA-UCNP).本研究选用双碘代氟硼二吡咯(BODIPY)作为三重态敏化剂,苝作为能量受体,大豆油作为溶剂.这些新合成的纳米胶囊不仅可以保持上转换体系处于溶液环境,并且可以有效阻隔氧气对三重态的猝灭,在水相中成功实现了高效的上转换发光.在该上转换纳米胶囊的制备过程中,我们研究了表面活性剂的种类、乙酸用量和钛酸丁酯用量对纳米胶囊上转换发光强度的影响,并通过透射电子显微镜(TEM)、扫描电子显微镜(SEM)和X射线光电子能谱(XPS)等对纳米胶囊结构进行表征和分析,成功制备了高效的TiO2纳米胶囊包覆的TTA上转换发光材料.

Triplet-triplet annihilation(TTA) upconversion is a technology that can convert low-energy light waves to high-energy light waves. The system is mainly composed of triplet sensitizers and energy receptors. The conversion mainly takes place in solution and is difficult to use as a whole molecule, which will greatly limit its application field. In this paper, by using the micelle soft template method to encapsulate the sensitizer and annihilant into the titanium dioxide shell, a highly efficient upconversion nanocapsule(TTA-UCNP) based on triplet-triplet annihilation upconversion was successfully prepared. In this study, BDP-I2 was used as the triplet sensitizer, perylene as the energy receptor, and soybean oil as the solvent. These newly synthesized nanocapsules can not only keep the upconversion system in a solution environment, but also effectively block the quenching of triplet states by oxygen, and successfully achieve efficient upconversion luminescence in the aqueous phase. In the preparation process of the upconversion nanocapsules, we studied the effects of the type of surfactant, the amount of acid and the amount of butyl titanate on the upconversion luminescence intensity of the nanocapsules. The structure of nanocapsules was characterized by transmission electron microscope(TEM), scanning electron microscope(SEM) and X-ray photoelectron spectroscopy(XPS), and a highly efficient TTA upconversion luminescent material coated with titanium dioxide nanocapsules was successfully prepared.