Abstract

The influence of the structure of the polymer matrix on the main photoluminescence characteristics of composites based on core (CdSe) and core–shell type (CdSe/ZnS) quantum dots embedded in liquid-crystalline and amorphous polymers of similar chemical structure is studied. The photoluminescence spectra consist of two bands (2.15 and 1.70 eV), the first of which corresponds to the radiative recombination of excitons, and the second one corresponds to carriers captured by traps at the quantum dot boundary. The second band is absent in the case of CdSe/ZnS quantum dots embedded in the liquid-crystalline polymer matrix. The kinetics of photoluminescence is well described by the sum of two decaying exponentials for CdSe quantum dots in matrices of both types and CdSe/ZnS quantum dots in the amorphous matrix. To determine the photoluminescence kinetics in the case of CdSe/ZnS quantum dots in the liquid-crystalline matrix, one exponential is sufficient. These effects are explained by the appearance of regions with closely spaced quantum dots, in which, in particular, the resonance transmission of excitation is possible.

中文翻译：

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非晶态和液晶聚合物矩阵中CdSe和CdSe / ZnS量子点的光致发光

摘要

研究了聚合物基质的结构对嵌入具有相似化学结构的液晶和无定形聚合物中的基于核（CdSe）和核-壳型（CdSe / ZnS）量子点的复合材料的主要光致发光特性的影响。光致发光光谱由两个波段（2.15和1.70 eV）组成，其中第一个对应于激子的辐射复合，第二个对应于被量子点边界处的陷阱捕获的载流子。在嵌入液晶聚合物基质中的CdSe / ZnS量子点的情况下，第二条带不存在。两种类型的矩阵中的CdSe量子点和非晶态矩阵中的CdSe / ZnS量子点的两个衰减指数之和很好地描述了光致发光的动力学。为了确定液晶基质中CdSe / ZnS量子点的光致发光动力学，一个指数就足够了。这些效应通过具有紧密间隔的量子点的区域的出现来解释，其中，特别是可以实现激发的共振传输。