Tesema Tefera Entele
Department of Chemistry, Prairie View A&M University, Prairie View, TX 77446, USA.
Nanomaterials (Basel). 2025 Jul 18;15(14):1113. doi: 10.3390/nano15141113.
This study explores the optical properties of a close-packed monolayer composed of core/shell-alloyed CdSeS/ZnS quantum dots (QDs) of two different sizes and compositions. The monolayers were self-assembled in a stacked configuration at the water/air interface using Langmuir-Blodgett (LB) techniques. Under continuous 532 nm laser illumination on the red absorption edge of the blue-emitting smaller QDs (QD450), the red-emitting larger QDs (QD645) exhibited oscillatory temporal dynamics in their photoluminescence (PL), characterized by a pronounced blueshift in the emission peak wavelength and an abrupt decrease in peak intensity. Conversely, excitation by a 405 nm laser on the blue absorption edge induced a drastic redshift in the emission wavelength over time. These significant shifts in emission spectra are attributed to photon- and anisotropic-strain-assisted interlayer atom transfer. The findings provide new insights into strain-driven atomic rearrangements and their impact on the photophysical behavior of QD systems.
本研究探索了由两种不同尺寸和组成的核/壳合金CdSeS/ZnS量子点（QD）构成的密排单层的光学性质。使用朗缪尔-布洛杰特（LB）技术，这些单层在水/空气界面以堆叠构型自组装。在连续532 nm激光照射发射蓝光的较小量子点（QD450）的红吸收边缘时，发射红光的较大量子点（QD645）在其光致发光（PL）中表现出振荡的时间动态，其特征是发射峰波长出现明显蓝移且峰强度突然下降。相反，用405 nm激光在蓝吸收边缘激发会随时间导致发射波长发生剧烈红移。发射光谱中的这些显著变化归因于光子和各向异性应变辅助的层间原子转移。这些发现为应变驱动的原子重排及其对量子点系统光物理行为的影响提供了新的见解。
