Enhancement of photoluminescence of ZnS:Mn nanocrystals modified by surfactants with phosphate or carboxyl groups via a reverse micelle method
Enhancement of photoluminescence of ZnS:Mn nanocrystals modified by surfactants with phosphate or carboxyl groups via a reverse micelle method
复制标题
DOI：
10.1016/s0022-2313(02)00296-x
复制
发表时间：
2002-08-01
影响因子：
3.6
通讯作者：
Senna, M
中科院分区：
文献类型：
--
作者：
Kubo, T;Isobe, T;Senna, M
在硫代琥珀酸双(2-乙基己基)钠反胶束中制备了硫化锌：锰纳米晶的胶体悬浮液，然后用含磷酸或羧基的表面活性剂对其进行修饰。由Mn2+离子的d-d跃迁引起的580 nm处的光致发光强度提高了6.3倍，量子效率从1.7%提高到8.1%。根据P-31核磁共振谱，含磷酸基团的表面活性剂吸附在纳米晶表面，与Mn2+的5个不成对的3d电子相互作用，P-31核自旋迅速松弛，表明磷酸基团位于Mn2+附近。磷酸盐或羧基发射的激发光谱与580 nm处的发射的激发光谱相似，对应于硫化锌的激发。两种激发光谱均随着表面活性剂用量的增加而平行移动，表现出线性关系。因此，我们将580 nm处量子效率的提高归因于ZnS官能团-->；Mn2+的额外能量转移，以及通过表面修饰减少了非辐射跃迁的能量损失。(C)2002 Elsevier Science B.V.保留所有权利。
A colloidal suspension of ZnS:Mn nanocrystals was prepared in sodium bis(2-ethylhexyl)suflosuccinate reverse micelles, and then modified by surfactants with phosphate or carboxyl groups. The photoluminescent intensity at 580 nm due to d-d transition of Mn2+ ions increases up to a factor of 6.3 and its quantum efficiency increases from 1.7% to 8.1% after modification. According to P-31 nuclear magnetic resonance spectra, surfactants with phosphate groups adsorb on the surface of ZnS nanocrystal and P-31 nucleus spins are relaxed rapidly by interaction with five unpaired 3d electrons of Mn2+, showing that phosphate groups are located in the vicinity of Mn2+. The excitation spectra for the emission due to phosphate or carboxyl groups are similar to those for the emission at 580nm corresponding to the excitation of ZnS. Both excitation spectra shift in parallel with increasing the amount of surfactant to show the linear relationship. We, therefore, attribute the increase in quantum efficiency at 580nm to additional energy transfer of ZnS functional groups-->Mn2+ as well as to the reduction of energy loss clue to non-radiative transition by surface modification. (C) 2002 Elsevier Science B.V. All rights reserved.