www.ijcrt.org © 2018 IJCRT | Volume 6, Issue 2 April 2018 | ISSN: 2320-2882
IJCRT1892138 International Journal of Creative Research Thoughts (IJCRT) www.ijcrt.org 898
GROWTH AND CHARACTERIZATION OF
UREA-THIOUREA DOPED TRIGLYCINE
SULPHATE SINGLE CRYSTALS
B.Leema Rose
1
,S.Narayana Kalkura
2
and C.Gnanasampantham
1*
1.Department of physics Research centre, S.T. Hindu college , Nagercoil, TamilNadu, India
2.Crystal Growth center,Anna University,Chennai
ABSTRACT
Ferroelectrics are an important class of electronic materials. Due to the demand of highly
sophisticated radiation and thermal detectors,electro-optical devices,imaging,recording and other
important applications in various sophisticated instrumentations, this field has gained significantly in its
scientific and technological values. Glycine derivative ,triglycine sulphate (TGS) , a well known
ferroelectric reflects a large pyroelectric coefficient and a high Volt/Watt sensitivity put in to thermoelectric
detector. In the present study 0.5mole % urea(NH2-CO-NH2) and 0.5 mole% thiourea(NH2-CS-NH2) was
put together and used as the double dopant.A single crystal with well defined crystal morphology was
obtained.The grown crystal was characterized for their morphological,structural,optical, SEM,EDAX and
non-linear optical properties.
Keywords
Amino acids,Urea,Thiourea, chiral carbon, non-centro symmetric, hydrophilic.
1.INTRODUCTION
In nature about 300 aminoacids occur. Most of the aminoacids are alpha aminoacids,which means
that the amino group is attached to the same carbon atom which the carboxyl groups is attached. Generally
aminoacids having an asymmetric carbon atom exhibit optical activity.Asymmetry arises when 4 different
groups are attached to the same carbon atom. Aminoacids posses second harmonic generation because of the
chiral carbon atom and crystallizes in non-centro symmetric space groups.
Among the twenty aminoacids , based on the structure, Glycine is the simplest aminoacid,
hydrophilic in nature and has no asymmetric carbon atom and therefore shows no optical activity.To get non
centro symmetric space groups selective acids such as sulphuric acid, phosphoric acids are used to convert
glycine into non centro symmetric space group.
Triglycine sulfate (TGS) (CH2NH2COOH)3·H2SO4, a ferroelectric discovered in 1956[1]. This noval
material may be considered a unique material for pyroelectric uses [2,3]. TGS undergoes second order phase
transition from paraelectric to ferroelectric state at Tc , 322 K which is followed by change of structural
space group of symmetry from P21/m to P21.Lattice parameters of TGS at room temperature are a = 9.392
Å, b = 12.734 Å, c = 5.784 Å and monoclinic angle β = 109.45 º [4].
2.EXPERIMENTAL
2.1. Materials
Analar grade glycine, Concentrated sulphuric acid , and triple distilled water were used for the synthesis of
TGS. Urea and Thiourea were used as the double dopants.