The aim of this work is the analysis of the evolution of titania nanoparticles based on their light emission spectra. Measurements are performed during the synthesis of the nanoparticles in a flame spray, which is irradiated by a pulsed IR laser. Due to the relatively high energy band gap of titania of about 3 eV, the observed substantial light absorption at the laser wavelength of 1.064 μm, i.e. within the region of titania transparency, makes our study novel and interesting.

Laser-induced light emission at different laser fluences is compared with spontaneous light emission from titania nanoparticles in flame. For signal processing, Wien plot is introduced to obtain the particle temperature. A peculiar feature of the temperature difference of the irradiated and nonirradiated particles versus laser fluence is obtained. Three well-defined regions of this fluence curve are observed and discussed with a particular attention on the plateau-like behavior at very low laser fluence, followed by a linear increase. An anomalously high titania absorption is inferred in the linear region.

The increase of the Urbach energy is speculated to account for the change in the optical properties of titania nanoparticles. It is related to structural defects, and, therefore, the presence of energy levels in the forbidden band due to the particular synthesis condition and/or induced by laser irradiation.

这项工作的目的是基于二氧化钛纳米粒子的发光光谱分析其演化。在以脉冲IR激光照射的火焰喷雾中，在纳米颗粒的合成过程中进行测量。由于二氧化钛的能量带隙相对较高，约为3 eV，因此在1.064μm的激光波长处（即在二氧化钛透明性区域内）观察到的大量光吸收使我们的研究新颖而有趣。

将不同激光注量下的激光诱导发光与火焰中二氧化钛纳米粒子的自发发光进行了比较。为了进行信号处理，引入维恩图以获得粒子温度。获得了被辐照和未辐照颗粒的温度差与激光通量的独特特征。观察和讨论了该通量曲线的三个明确区域，并特别注意在非常低的激光通量下的平台状行为，然后线性增加。在线性区域推断出异常高的二氧化钛吸收。

推测Urbach能量的增加可解释二氧化钛纳米粒子光学性质的变化。它与结构缺陷有关，因此与禁带中由于特定的合成条件和/或由激光辐照引起的能级的存在有关。