Mg掺杂TiO_2纳米晶光氧化还原染料的可逆颜色转变研究

Enhanced Photoreversible Color Switching of Methylene Blue Catalyzed by Magnesium-doped TiO_2 Nanocrystals

由于非直接接触、远程控制、高效及快捷的优点,光可逆颜色转换材料在信息存储、显示器件、传感器等领域有着重要应用。复合无机材料和有机材料,实现协同增效,是新型光驱动可逆颜色转换材料的研究热点之一。本研究采用一步液相合成法制备粒径约为5 nm的锐钛矿型Mg^(2+)掺杂TiO_2纳米晶,通过X射线衍射、透射电子显微镜、X射线光电子能谱、红外光谱和拉曼光谱等表征手段确认材料的组成结构,并对比研究了Mg^(2+)掺杂TiO_2对亚甲基蓝(MB)光可逆颜色转换性能的增强效应。结果表明,掺杂Mg^(2+)在TiO_2晶格中能产生杂质能级,有效抑制了光生载流子的复合,提高了TiO_2光氧化还原MB的活性;另一方面,掺杂Mg^(2+)降低了TiO_2纳米晶的吸收波长,在可见光照射下能够有效地抑制MB向还原态LMB的转变,提高系统着色速率。这种基于碱金属掺杂TiO_2纳米晶的光可逆颜色转换材料在许多光电子器件领域具有潜在的应用价值。

Because the advantages of non-direct contact, remote control, high efficiency and fastness, light-driven reversible color switching materials （LDRCSMs） have important applications in information storage, display devices, sensors, and other fields. The combination of inorganic materials and organic materials to achieve synergies is one of the research hotspots of new LDRCSMs. A one＇step liquid-phase synthesis method was used to prepare Mg-doped TiO2 nanocrystals （Mg-TiO2 NCs） with a particle size of-5 nm. The reversible light-responsive color switching of methylene blue （MB） by using Mg-TiO2 NCs was investigated. The results show that Mg2＋ doping generates impurity levels in the TiO- lattice, effectively inhibiting the recombination of photogenerated carriers and increasing the activity of TiO2 photooxidation-reduced MB. On the other hand, Mg2＋ doping can decrease the absorption wavelength of TiO2 NCs, which effectively represses the partial reduction of MB to reduced LMB under visible light irradiation, leading to a higher recoloration rate. Such LDRCSMs based on alkali metal-doped TiO2 NCs may have potential application in many optoelectronic device fields.