Gonzales Leandro Lemos, da Silva Hartwig Marlon, Fassbender Rafael Uarth, Moreira Eduardo Ceretta, Pereira Marcelo Barbalho, Jardim Pedro Lovato Gomes, Raubach Cristiane Wienke, Moreira Mário Lucio, da Silva Cava Sérgio
Instituto Federal de Educação, Ciência e Tecnologia Sul-rio-Grandense, Pelotas, RS, Brazil.
Universidade Federal de Pelotas, Pelotas RS, Brazil.
Heliyon. 2021 Mar 16;7(3):e06521. doi: 10.1016/j.heliyon.2021.e06521. eCollection 2021 Mar.
Zinc titanates are compounds that have shown great application versatility, including in the field of semiconductors. Solid state reactions, the polymeric precursor method and the hydrothermal method are the most mentioned synthesis of these compounds in the literature. In the present work, we use microwave assisted hydrothermal method (MAH) to synthesize zinc titanate and evaluate its potential for solar cell applications through structural and optical characterization techniques. The synthesized samples were also subjected to a variable temperature heat treatment in the range of 500 °C-800 °C. The analysis showed that the crystallization of the material starts at 500 °C and that samples submitted to temperatures of 600 °C-800 °C showed the formation of two phases of zinc titanates, being a cubic phase of ZnTiO, considered rare in the literature, predominant up to a temperature of 800 °C. The optical characterization, based on the techniques of photoluminescence spectroscopy and UV-Visible spectroscopy, showed that the photoluminescent activity and the energy of the band gap increased with the increase of the temperature of the heat treatment, having the highest response in 700 °C, facts that can be linked to the predominant formation of the cubic phase of ZnTiO and simultaneous of the cubic and rhombohedral phases of ZnTiO at 700 and 800 °C. Finally, we highlight as the most important results, the fact that it was possible to obtain these titanates at a temperature lower than that reported in the literature, and that the heat-treated sample at 500 °C is the one with the lowest energy expenditure to be synthesized and the one with the greatest potential for application in dye-sensitized solar cells (DSSC's).
钛酸锌是一类展现出广泛应用多样性的化合物，包括在半导体领域。固态反应、聚合物前驱体法和水热法是文献中最常提及的合成这些化合物的方法。在本工作中，我们采用微波辅助水热法（MAH）合成钛酸锌，并通过结构和光学表征技术评估其在太阳能电池应用方面的潜力。合成的样品还在500℃至800℃范围内进行了变温热处理。分析表明，材料的结晶在500℃开始，且在600℃至800℃温度下处理的样品显示出两种钛酸锌相的形成，其中ZnTiO的立方相在文献中较为罕见，在高达800℃的温度下占主导地位。基于光致发光光谱和紫外-可见光谱技术的光学表征表明，光致发光活性和带隙能量随热处理温度的升高而增加，在700℃时响应最高，这些事实可与ZnTiO立方相的主导形成以及在700℃和800℃时ZnTiO立方相和菱面体相的同时形成相关联。最后，我们强调最重要的结果是，有可能在低于文献报道的温度下获得这些钛酸盐，并且在500℃热处理的样品是合成时能量消耗最低且在染料敏化太阳能电池（DSSC）中应用潜力最大的样品。
