中文摘要：

采用成核掺杂法制备了高效发光的ZnSeS：Mn量子点,并通过稳态光致发光光谱以及时间分辨光谱研究了量子点的发光热稳定性。厚壳层的ZnSeS：Mn量子点的发光量子效率可以达到50%。温度从80K升高到500K,量子点的发光峰位逐渐蓝移,发光线宽逐渐展宽,发光强度逐渐减弱。通过对比具有不同壳层厚度的ZnSeS：Mn量子点的发光强度与荧光寿命,对ZnSeS：MnQDs的发光热猝灭机理进行了研究。对于厚壳层样品,其发光强度与荧光寿命的变化趋势相一致,表明从ZnSeS基质到Mn^2＋的能量传递效率不受温度的影响。对于薄壳层样品,发光强度的衰减明显快于荧光寿命的衰减,这意味着温度升高导致了从ZnSeS基质到Mn^2＋的能量传递效率降低。上述实验结果表明,增加壳层厚度是减少无辐射复合过程及增加量子点热稳定性的有效方法。

英文摘要：

The photoluminescence （PL） thermal stability of ZnSeS：Mn quantum dots （QDs） synthesized by a nucleation -doping strategy was studied via steady - state and time - resolved PL spectroscopy. Through coating a thick ZnSeS shell on the MnSe core, the quantum yield of the resulting ZnSeS：Mn （MnSe/ZnSeS） QDs could reach up to 50%. With the temperature increasing from 80 to 500 K, it was found that the PL peak energy of ZnSeS： Mn QDs shifted to blue, the bandwidth broadened, and the PL intensity decreased. The PL thermal quenching mechanism for ZnSeS ： Mn QDs were studied by comparing the PL intensity and lifetime of QDs with different shell thickness. Surprisingly, for thick shell QDs, the PL intensity and lifetime exhibited the same changing trend, which indicated that the energy transfer efficiency from ZnSeS host to Mn^2 ＋ ions showed nearly no dependence on the temperature. While, for the thin shell ones, the PL intensity reduced faster than the PL lifetime, which meant that the energy transfer efficiency from ZnSeS host to Mn^2＋ ions dropped as the temperature increased. The experimental results suggested that passivating the QDs surface states with a thick shell was an effective way to decrease the nonradiative relaxation of QDs and improve the thermal stability of ZnSeS： Mn QDs.