Abstract:
The urge for a renewable energy source to take over the conventional fossil energy sources
has always been a necessity. Thus a lot of work and effort has been spend on the photovoltaic
cell research which focuses on conversion of solar energy into electrical energy. The studies
in this field so far had classified the photovoltaic cells into first, second and third generation
cells with the common single crystalline silicon solar cells being the first generation, thin film
solar cells are the second generation and third generations consists of nanocrystalline
materials, polymer materials, perovskite materials or some hybrid materials which give hopes
on a cost effective as well as efficient production of a photovoltaic cell. Basically third
generation solar cells are not limited by the Schottky-Queisser limit of power efficiency and
can be efficient beyond even ~90%. This however, is yet a dream and not realized so far in
any practical solar cell fabricated. Attempts are therefore made to improve the photovoltaic
cells using different concepts.
In this project attempt is to investigate the effect of different shapes and sizes of the
gold/silver nanoparticles on trapping the light since efficient trapping of light is needed to
increase the cell efficiency. Gold and silver nanoparticles exhibit absorption of
electromagnetic radiation in the visible part of the electromagnetic spectrum known as
Localized Surface Plasmon Resonance (LSPR). The use of anisotropic nanoparticles like
rods, tetrapods, triangles, stars, cubes etc. have size and shape dependent much broader
absorption properties which can extend in the visible range to IR, the part of the solar
spectrum which in most of the cases is not possible to use. One can also make alloy
plasmonic structures which also can affect the absorption favourably to improve the
performance.
In this project, nanoparticles of spherical, rod, stars, cubes and cage shapes of gold and silver
were synthesized and their characterization was performed using UV-Visible
spectrophotometer and FESEM. Then they are introduced into the widely used conductive
polymer PEDOT:PSS (Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) and their
optical and electrical properties in solution and thin film are studied for measuring their light
trapping efficiency
