Abstract Conducted research presents a rapid and cost-effective approach to technological processing of screen-printed films with anatase TiO 2 nanoparticles, by utilizing the high fluence laser radiation. The influence of laser sintering on the screen-printed films was characterized with optical and scanning electron microscopy, energy-dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, nanoindenter measurements and current vs voltage measurements. Investigation of surface morphology of screen-printed films revealed that higher laser fluences caused significant decrease in film thickness, trough evaporation of organic additives used in the paste matrix. EDX mapping of carbon content in untreated and laser sintered surface confirmed removal of organic additives. Laser sintering stimulated breaking of large agglomerates into much finer nano-sized particles and promoted formation of necking between individual grains. Crystal structure and vibrational properties of anatase TiO 2 nanoparticles was monitored with Raman spectroscopy before and after laser sintering. Obtained results point out that anatase polymorph was preserved during the sintering process, without appearance of other phases. From observation of the behavior of the most intense E g Raman active mode it was deduced that laser sintering provoked a formation of structural defects i.e. oxygen vacancies in TiO 2 nanoparticles, whose concentration increased in the samples treated with higher laser fluences. Mechanical properties of untreated and laser sintered samples were investigated with nanoindenter measurements using several load forces, in order to carefully probe the Young modulus and mechanical hardness. From the analysis of collected data, we established that overall improvement of the mechanical properties with laser sintering originates from formation of very dense ceramic layer with enhanced interconnectivity between individual TiO 2 nanoparticles. Measurements of current vs voltage characteristics clearly demonstrated that increase in laser fluence leads to drastic increase in current values and improvement of electric conductivity.

中文翻译：

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丝网印刷 TiO 2 纳米粒子的激光烧结以改善机械和电学性能

摘要 所进行的研究提出了一种利用高能量密度激光辐射技术处理具有锐钛矿 TiO 2 纳米颗粒的丝网印刷薄膜的快速且具有成本效益的方法。激光烧结对丝网印刷薄膜的影响通过光学和扫描电子显微镜、能量色散 X 射线 (EDX) 光谱、拉曼光谱、纳米压痕测量和电流与电压测量进行表征。丝网印刷薄膜的表面形态研究表明，较高的激光能量密度会导致薄膜厚度显着降低，这是通过浆料基质中使用的有机添加剂的蒸发。未处理和激光烧结表面碳含量的 EDX 映射证实去除了有机添加剂。激光烧结刺激大团块破碎成更细的纳米级颗粒，并促进单个颗粒之间颈缩的形成。在激光烧结前后用拉曼光谱监测锐钛矿TiO 2 纳米颗粒的晶体结构和振动特性。得到的结果表明，在烧结过程中保留了锐钛矿多晶型物，没有出现其他相。根据对最强E g 拉曼活性模式的行为的观察，推断激光烧结引起结构缺陷的形成，即TiO 2 纳米颗粒中的氧空位，其浓度在用较高激光能量密度处理的样品中增加。未处理和激光烧结样品的机械性能通过使用几种载荷力的纳米压痕测量进行研究，以便仔细探测杨氏模量和机械硬度。根据对收集到的数据的分析，我们确定激光烧结机械性能的整体改进源于形成非常致密的陶瓷层，并增强了单个 TiO 2 纳米颗粒之间的互连性。电流与电压特性的测量清楚地表明，激光能量密度的增加导致电流值的急剧增加和电导率的改善。