Huang Lu, Li Zhichun, Zhang Congyang, Kong Long, Wang Bo, Huang Shouqiang, Sharma Vaishali, Ma Houyu, Yuan Qingchen, Liu Yue, Shen Guoqing, Wu Kaifeng, Li Liang
School of Environmental Science and Engineering , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China . Email:
School of Agriculture and Biology , Shanghai Jiao Tong University , 800 Dongchuan Road , Shanghai 200240 , China.
Chem Sci. 2019 May 30;10(27):6683-6688. doi: 10.1039/c9sc01233h. eCollection 2019 Jul 21.
Growth of metal oxide layers on quantum dots (QDs) has been regarded as a good way to improve the photostability of QDs. However, direct growth of metal oxides on individual QD remains a great challenge. Here we report a novel approach to rapidly anchor metal oxides on QD surfaces through a sacrificial oxidation of a self-metal source strategy. As typical core/shell QDs, CdSe/CdS or aluminum doped CdSe/CdS (CdSe/CdS:Al) QDs were chosen and treated with peroxide (benzoyl peroxide). Self-metal sources (cadmium or/and aluminum) can be easily sacrificially oxidized, leading to the quick growth of cadmium oxide (CdO) or aluminum/cadmium hybrid oxides (AlO/CdO) on the surface of individual QD for improved photostability. Compared with CdO, AlO possesses excellent barrier properties against moisture and oxygen. Therefore, CdSe/CdS QDs with the protection of an AlO/CdO hybrid layer show much superior photostability. Under strong illumination with blue light, the QDs coated with the AlO/CdO hybrid layer retained 100% of the original photoluminescence intensity after 70 h, while that of the untreated CdSe/CdS:Al, the treated CdSe/CdS and the CdSe/CdS QDs dropped to 65%, 45%, and 5%, respectively. Furthermore, we demonstrate that this method can be extended to other metal-doped QD systems, even including some inactive metals difficult to be oxidized spontaneously in an ambient atmosphere, which provides a new way to stabilize QDs for diverse optoelectronic applications.
在量子点（QD）上生长金属氧化物层被认为是提高量子点光稳定性的一种好方法。然而，在单个量子点上直接生长金属氧化物仍然是一个巨大的挑战。在此，我们报告了一种新颖的方法，即通过自金属源牺牲氧化策略在量子点表面快速锚定金属氧化物。作为典型的核壳量子点，选择了CdSe/CdS或铝掺杂的CdSe/CdS（CdSe/CdS:Al）量子点并用过氧化物（过氧化苯甲酰）进行处理。自金属源（镉或/和铝）可以很容易地被牺牲氧化，导致在单个量子点表面快速生长氧化镉（CdO）或铝/镉混合氧化物（AlO/CdO），从而提高光稳定性。与CdO相比，AlO对水分和氧气具有优异的阻隔性能。因此，具有AlO/CdO混合层保护的CdSe/CdS量子点表现出优越得多的光稳定性。在蓝光强照射下，涂覆有AlO/CdO混合层的量子点在70小时后保留了100%的原始光致发光强度，而未处理的CdSe/CdS:Al、处理过的CdSe/CdS和CdSe/CdS量子点的光致发光强度分别降至65%、45%和5%。此外，我们证明这种方法可以扩展到其他金属掺杂的量子点系统，甚至包括一些在环境气氛中难以自发氧化的惰性金属，这为稳定量子点用于各种光电子应用提供了一种新方法。
