掺杂有不同量的Nd3+的TiO2纳米颗粒(0.5、1和3wt。%)通过溶胶-凝胶法合成,并使用Nd3的热敏辐射跃迁之间的荧光强度比评估为潜在的温度纳米探针。XRD表征确定了所有掺杂样品中的锐钛矿相。用SEM观察纳米粒子的形貌,TEM和HRTEM显微镜。通过EDXS获得TiO2中Nd3+的相对量,并通过XPS和NEXAFS研究了钛和钕的氧化态,分别。Nd3+存在于所有样品中,与钛不同,除了Ti4+,观察到显著量的Ti3+;Ti3+的相对浓度随着TiO2纳米颗粒中Nd3+的量增加而增加。研究了合成纳米粒子的光致发光,350,514和600nm的激发波长。当Nd3浓度增加时,与TiO2中缺陷的存在有关的宽带的发射强度增加。使用600nm激发,Nd3+离子的4F7/2→4I9/2、4F5/2→4I9/2和4F3/2→4I9/2跃迁,以760nm为中心,821nm,和880纳米,分别,被观察到。最后,研究了温度对合成纳米粒子光致发光强度的影响,具有600nm的激发波长。在288-348K范围内收集光谱。为了提高温度,4F7/2→4I9/2和4F5/2→4I9/2跃迁的发射强度显著增加,与4F3/2→4I9/2过渡相反,其中强度发射下降。跃迁I821I880=F5/24I49/2F43/2I49/2和I760I880=F47/2I49/2F43/2I49/2之间的荧光强度比用于计算传感器的相对灵敏度。I760I880的相对灵敏度接近3%K-1,I821I880的相对灵敏度接近1%K-1。
TiO2 nanoparticles doped with different amounts of Nd3+ (0.5, 1, and 3 wt.%) were synthetized by the sol-gel method, and evaluated as potential temperature nanoprobes using the fluorescence intensity ratio between thermal-sensitive radiative transitions of the Nd3+. XRD characterization identified the anatase phase in all the doped samples. The morphology of the nanoparticles was observed with SEM, TEM and HRTEM microscopies. The relative amount of Nd3+ in TiO2 was obtained by EDXS, and the oxidation state of titanium and neodymium was investigated via XPS and NEXAFS, respectively. Nd3+ was present in all the samples, unlike titanium, where besides Ti4+, a significantly amount of Ti3+ was observed; the relative concentration of Ti3+ increased as the amount of Nd3+ in the TiO2 nanoparticles increased. The photoluminescence of the synthetized nanoparticles was investigated, with excitation wavelengths of 350, 514 and 600 nm. The emission intensity of the broad band that was associated with the presence of defects in the TiO2, increased when the concentration of Nd3+ was increased. Using 600 nm for excitation, the 4F7/2→4I9/2, 4F5/2→4I9/2 and 4F3/2→4I9/2 transitions of Nd3+ ions, centered at 760 nm, 821 nm, and 880 nm, respectively, were observed. Finally, the effect of temperature in the photoluminescence intensity of the synthetized nanoparticles was investigated, with an excitation wavelength of 600 nm. The spectra were collected in the 288-348 K range. For increasing temperatures, the emission intensity of the 4F7/2→4I9/2 and 4F5/2→4I9/2 transitions increased significantly, in contrast to the 4F3/2→4I9/2 transition, in which the intensity emission decreased. The fluorescence intensity ratio between the transitions I821I880=F5/24I49/2F43/2I49/2 and I760I880=F47/2I49/2F43/2I49/2 were used to calculate the relative sensitivity of the sensors. The relative sensitivity was near 3% K-1 for I760I880 and near 1% K-1 for I821I880.