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The Effect of the Temperature-Time Mode of Crystallization on the Photoluminescence and Dielectric Properties of PVC/TiO2 Nanocomposites
Integrated Ferroelectrics ( IF 0.7 ) Pub Date : 2020-11-11 , DOI: 10.1080/10584587.2020.1819035
Mahammadali A. Ramazanov 1 , Almara M. Rahimli 1
Affiliation  

Abstract This study investigates the effect of different cooling rates on the dielectric constant and loss tangent of a system of TiO2 nanoparticles dispersed in a PVC matrix. Experimental results show that at high frequencies, the dielectric loss tangent of nanocomposites increases sharply due to the increased energy dispersions at high frequencies and a sharp increase in alternating electrical conductivity. On the other hand, the sharp decrease in dielectric constant is explained by the decrease in the polarizing ability of nanocomposites at high frequencies. It was found that for PVC/3%TiO2 based nanocomposites photoluminescence intensity strongly changes depending on the temperature-time mode of crystallization. PL intensity at all wavelengths increases sharply at the cooling rate of film β1 = 2°/min, as compared with the samples obtained at the cooling rate of β2= 200°/min and in the case of cooling rate β3 = 2000°/min. The increase of PL intensity depending on the β is explained by the fact that the supramolecular structure of the polymer changes forming large crystallites in the polymer, resulting in stronger interfacial interaction between the nanoparticles and the matrix which in turn increases the luminescence intensity. SEM images indicated that for the samples obtained at different cooling rates, the size of TiO2 nanoparticles are practically unchanged, but the supramolecular structure of the matrix changes.

中文翻译:

结晶温度-时间模式对PVC/TiO2纳米复合材料光致发光和介电性能的影响

摘要 本研究研究了不同冷却速率对分散在 PVC 基体中的 TiO2 纳米粒子系统的介电常数和损耗角正切的影响。实验结果表明,在高频下,由于高频下能量色散的增加和交变电导率的急剧增加,纳米复合材料的介电损耗角正切急剧增加。另一方面,介电常数的急剧下降可以用纳米复合材料在高频下极化能力的下降来解释。发现对于基于 PVC/3%TiO2 的纳米复合材料,光致发光强度根据结晶的温度-时间模式发生强烈变化。在薄膜冷却速度 β1 = 2°/min 时,所有波长的 PL 强度急剧增加,与冷却速度为 β2=200°/min 和冷却速度为 β3=2000°/min 时获得的样品相比。取决于 β 的 PL 强度增加的原因是聚合物的超分子结构发生变化,在聚合物中形成大的微晶,导致纳米颗粒与基质之间更强的界面相互作用,从而增加了发光强度。SEM 图像表明,对于不同冷却速率下获得的样品,TiO2 纳米颗粒的尺寸几乎没有变化,但基体的超分子结构发生了变化。取决于 β 的 PL 强度增加的原因是聚合物的超分子结构发生变化,在聚合物中形成大的微晶,导致纳米颗粒和基质之间更强的界面相互作用,从而增加了发光强度。SEM图像表明,对于不同冷却速率下获得的样品,TiO2纳米颗粒的尺寸几乎没有变化,但基体的超分子结构发生了变化。取决于 β 的 PL 强度增加的原因是聚合物的超分子结构发生变化,在聚合物中形成大的微晶,导致纳米颗粒与基质之间更强的界面相互作用,从而增加了发光强度。SEM图像表明,对于不同冷却速率下获得的样品,TiO2纳米颗粒的尺寸几乎没有变化,但基体的超分子结构发生了变化。
更新日期:2020-11-11
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