Record Details

Enhanced photoluminescence of CdS nanocrystallites in LB multilayers on aqueous treatment

DSpace at IIT Bombay

View Archive Info
 
 
Field Value
 
Title Enhanced photoluminescence of CdS nanocrystallites in LB multilayers on aqueous treatment
 
Creator NARAYANAM, PK
SRINIVASA, RS
TALWAR, SS
MAJOR, SS
 
Subject LANGMUIR-BLODGETT-FILMS
QUANTIZED CADMIUM-SULFIDE
QUANTUM DOTS
SEMICONDUCTOR CLUSTERS
ARACHIDATE MONOLAYERS
OPTICAL-PROPERTIES
ELECTRONIC-STATE
PARTICLES
TEMPERATURE
DEPENDENCE
Cadmium sulphide
Nanocrystallites
LB multilayers
Photoluminescence
 
Description CdS nanocrystallites were formed within the LB matrix of cadmium arachidate-arachidic acid composite multilayer by post deposition H(2)S exposure of precursor cadmium arachidate multilayer. The CdS containing multilayers were subjected to post deposition heat treatment in air in the temperature range of 100-300 degrees C. either directly after the sulphidation process or after being introduced into an aqueous bath. FT-IR spectroscopy was used to study the chemical changes in composite multilayers at different stages of processing. Optical properties of the CdS nanocrystallites were studied by UV-VIS absorption and photoluminescence measurements. A strong enhancement of excitonic emission and suppression of surface states emission from CdS nanocrystallites was observed after heat treatment at 100-150 degrees C in the case of aqueous treated composite multilayer. X ray reflection and atomic force microscopy show that the aqueous treatment results in expulsion of arachidic acid to the surface of the multilayer resulting in its facile removal during heat treatment. These results suggest that the response to heat treatment of the composite multilayer containing CdS nanocrystallites depends critically on the proximity and access of the unreacted cadmium arachidate to CdS nanocrystallites. This in turn, provides Cd ions for the passivation of Cd vacancies on the surface of nanocrystallites resulting in a strong enhancement of excitonic emission. Heat treatment at higher temperatures results in drastic reduction of photoluminescence, due to particle growth as well as removal of organic moieties. (C) 2011 Elsevier B.V. All rights reserved.
 
Publisher ELSEVIER SCIENCE BV
 
Date 2012-06-26T06:28:19Z
2012-06-26T06:28:19Z
2011
 
Type Article
 
Identifier COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS,380(1-3)292-299
0927-7757
http://dx.doi.org/10.1016/j.colsurfa.2011.02.054
http://dspace.library.iitb.ac.in/jspui/handle/100/14037
 
Language English