PHOTOELECTROCHEMISTRY IN SEMICONDUCTOR PARTICULATE SYSTEMS .13. SURFACE MODIFICATION OF CDS SEMICONDUCTOR COLLOIDS WITH DIETHYLDITHIOCARBAMATE
PHOTOELECTROCHEMISTRY IN SEMICONDUCTOR PARTICULATE SYSTEMS .13. SURFACE MODIFICATION OF CDS SEMICONDUCTOR COLLOIDS WITH DIETHYLDITHIOCARBAMATE
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DOI：
10.1021/j100347a069
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发表时间：
1989-05-18
影响因子：
--
通讯作者：
DIMITRIJEVIC, NM
中科院分区：
文献类型：
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作者：
KAMAT, PV;DIMITRIJEVIC, NM
CdS胶体与二乙基二硫代氨基甲酸根阴离子（Et 2NCS 2-）的络合分两个阶段进行。Et 2NCS 2-与CdS表面的相互作用最初导致CdS胶体的部分溶解，但是在高浓度（> ImM）的Et 2NCS 2-下在可见光（λ max ~ 610 nm）中产生新的吸收带。这两个过程的缔合常数分别为1900和170 M-1。用Et 2NCS 2-进行表面改性降低了胶体CdS的发射产率以及发射衰减寿命。激光脉冲激发（355 nm）的CdS胶体在Et_2NCS_2 ~* 存在下，导致Et_2NCS_2 ~* 自由基的形成，它在620 nm处有最大吸收。已经发现该氧化过程的量子产率为0.2。光电化学产生的Et 2NCS 2 * 自由基在乙腈溶液中以4.6 × 109 M-1 s-1的速率常数经历二聚化。
CdS colloids undergo complexation with diethyldithiocarbamate anions (Et2NCS2~) in two stages. Interactionof Et2NCS2" with CdS surface initially results in partial dissolution of CdS colloids, but a new absorption band in the visible (Xmax~ 610 nm) develops at high concentrations (> 1 mM) of Et2NCS2~. The association constants for these two processes have been determined to be 1900 and 170 M" 1, respectively. Surface modification with Et2NCS2" decreases the emission yield as well as the emission decay lifetime of colloidal CdS. Laser pulse excitation (355 nm) of CdS colloids in the presence of Et2NCS2" leads to the formationof Et2NCS2* radical, which has an absorption maximum at 620 nm. The quantum yield for this oxidation process has been found to be 0.2. Photoelectrochemically produced Et2NCS2* radical undergoes dimerization with a rate constant of 4.6 X 109 M" 1 s" 1 in acetonitrile solution.