Photoluminescence of CdSe/ZnS/TOPO nanocrystals expanded on silica glass substrates: Adsorption and desorption effects of polar molecules on nanocrystal surfaces
Photoluminescence of CdSe/ZnS/TOPO nanocrystals expanded on silica glass substrates: Adsorption and desorption effects of polar molecules on nanocrystal surfaces
复制标题
DOI：
10.1016/j.jlumin.2006.01.052
复制
发表时间：
2006-07
影响因子：
3.6
通讯作者：
M. Oda;J. Tsukamoto;A. Hasegawa;Noriya Iwami;Kengou Nishiura;I. Hagiwara;N. Ando;H. Horiuchi;T. Tani
中科院分区：
文献类型：
--
作者：
M. Oda;J. Tsukamoto;A. Hasegawa;Noriya Iwami;Kengou Nishiura;I. Hagiwara;N. Ando;H. Horiuchi;T. Tani
研究了CdSe/ZnS/TOPO纳米晶在一个大气压下不同气体中的光致发光特性。在488 nm连续光照射下，所有情况下的PL强度随光谱移动而增加。特别是，PL强度增加超过2倍后，1200 s的照射在氮气饱和的极性分子，如水和NH3的蒸汽。当样品在连续光照射下抽真空时，随着光谱位移而增加的PL强度大部分恢复到其先前的值。这些结果表明，极性分子在NC表面上的光吸附提供了一些可逆的恢复功能的PL淬灭缺陷或陷阱的表面或附近的网站。NC曲面上陷阱位置的存在已经被广泛地引入用于描述例如，闪烁现象假设这些陷阱的一部分被充电，我们建议的光致效应可以被理解为电荷补偿失活的陷阱网站由于极性分子的吸附一致。
We have investigated photoluminescence (PL) properties of CdSe/ZnS/TOPO nanocrystals (NCs) in various kinds of gases at one atmospheric pressure. Increase of PL intensity with spectral shift is observed under 488nm cw light irradiation in all cases. Especially, the PL intensity increases more than twice after 1200s irradiation in nitrogen gases saturated with vapor of polar molecules, such as H2O and NH3. The increased PL intensity with the spectral shift mostly recovers to its previous values when the sample is evacuated under continuous light irradiation. These results indicate that photo-adsorption of the polar molecules onto NC surfaces provides some reversible restoring functions to the PL quenching defects or trap sites on or near the surfaces. The existence of the trap sites on NC surfaces is already widely introduced for describing e.g., blinking phenomena. Assuming part of these traps being charged, we propose the photo-induced effects can be understood as charge-compensated inactivation of the trap sites due to the adsorption of the polar molecules consistently.