CHEM01200604009 Sreejith Kaniyankandy - Homi Bhabha ...

CHAPTER 1: GENERAL INTRODUCTION
This chapter gives a brief introduction to nanotechnology and basic semiconductor
physics and electronic structure of a bulk crystal with simple quantum mechanical models. A
brief description of theoretical framework based on effective mass approximation to describe
changes in electronic structure with size. Typical band structures in real systems like CdSe,
CdTe etc is also described. A brief account of processes involved in relaxation of carriers on
photoexcitation is described. Methods to improve the relaxation behavior are also discussed
with particular emphasis on core shell and metal semiconductor nanostructure. A concise
description of Marcus theory of electron transfer which gives the theoretical framework for
electron transfer is also outlined. Additionally brief discussion on types of electron transfer
processes, adiabatic and non adiabatic is included. Importance of synthesis conditions to
obtain monodisperse particles is delineated along with synthesis technique used in present
thesis for II-VI QDs.
CHAPTER 2: EXPERIMENTAL TECHNIQUE
A summary of experimental techniques used in this thesis for characterization of
materials to dynamics study is described in this chapter. A brief outline of transmission
electron microscope and additional information like electron diffraction and elemental
analysis is outlined. Additionally description of steady state UV-Vis absorption,
photoluminescence spectroscopy is also delineated. A brief description Time correlated
single photon counting technique and instrumentations involved is explained. Hot exciton
relaxation in QDs takes place in the femtosecond time scale, to study ultrafast phenomena we
have used Femtosecond Transient absorption spectroscopy. Basic techniques involved in
generation of a femtosecond pulse, amplification and characterization is described.
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