中国光学, 2015, 8 (5): 806, 网络出版: 2015-11-30
Mn 掺杂ZnSe 量子点变温发光性质研究
Temperature-dependent photoluminescence properties of Mn-doped ZnSe quantum dots
量子点 纳米晶 Mn掺杂量子点 发光性质 热猝灭 quantum dots nanocrystal Mn-doped quantum dots luminescence property thermal quenching
摘要
量子点(QD)照明器件中电流导致的焦耳热会使其工作温度高于室温?因此研究量子点的发光热稳定性十分重要。本文利用稳态光谱和时间分辨光谱研究了具有不同壳层厚度的Mn掺杂ZnSe(Mn:ZnSe)量子点的变温发光性质, 温度范围是80~500 K。实验结果表明, 厚壳层(65单层(MLs))Mn∶ZnSe量子点的发光热稳定性要优于薄壳层(26 MLs)的量子点。从80 K升温到400 K的过程中, 厚壳层Mn∶ZnSe量子点的发光几乎没有发生热猝灭, 发光量子效率在400 K高温下依然可以达到60%。通过对比Mn∶ZnSe量子点的变温发光强度与荧光寿命, 对Mn∶ZnSe量子点发光热猝灭机制进行了讨论。最后, 为了研究Mn∶ZnSe量子点的发光热猝灭是否为本征猝灭, 对具有不同壳层厚度的Mn∶ZnSe量子点进行了加热-冷却循环(300-500-300 K)测试, 发现厚壳层的Mn∶ZnSe量子点的发光在循环中基本可逆。因此, Mn∶ZnSe量子点可以适用于照明器件, 即使器件中会出现不可避免的较强热效应。
Abstract
Thermal stability of quantum dot(QD) luminescence is considered as an important factor for their applications in luminescent devices because of the Joule heat caused by inevitable current. The temperature-dependent photoluminescence(PL) properties of Mn-doped ZnSe(Mn∶ZnSe) QDs with different shell thickness in the temperature range from 80 to 500 K were studied by steady-state and time-resolved PL spectra. It was found that the Mn∶ZnSe QDs with thick shell(65 monolayers(MLs)) exhibited better PL thermal stability than the thin shell coated ones(26 MLs). Because almost no PL quenching occurred for thick shell-coated Mn-doped QDs from 80 to 400 K, their PL quantum yield(QY) could keep 60% even at 400 K. Moreover, based on the change in temperature-dependent PL intensities and lifetimes of Mn∶ZnSe QDs, the thermal quenching mechanism was proposed. Finally, the stability of Mn∶ZnSe QDs with different shell thickness are discussed on the basis of heating-cooling cycling examination(300-500-300 K). For Mn∶ZnSe QDs with thick shell, the PL was nearly totally recovered after the cycling examination. Thus, Mn∶ZnSe QDs are promising for applications in luminescent devices, where strong thermal effect is inevitable.
袁曦, 郑金桔, 李海波, 赵家龙. Mn 掺杂ZnSe 量子点变温发光性质研究[J]. 中国光学, 2015, 8(5): 806. YUAN Xi, ZHENG Jin-ju, LI Hai-bo, ZHAO Jia-long. Temperature-dependent photoluminescence properties of Mn-doped ZnSe quantum dots[J]. Chinese Optics, 2015, 8(5): 806.