Insights into Structural and Optical Properties of ZnO Nanoparticles

Abstract

ZnO nanoparticles have been synthesized from zinc nitrate as precursor and potassium hydroxide as precipitating agent using precipitation method. The prepared nanoparticles were characterized by using X-ray diffraction, Fourier Transform Infrared Spectroscopy (FTIR) and UV-Visible Spectroscopy analysis confirmed the formation of ZnO nanoparticles having hexagonal unit cell and wurtzite structure. The FTIR analysis provided information about the presence of functional groups in prepared nanoparticles. The UV-Vis absorption spectrum showed prominent peaks near to 360nm range whereas small peaks were also seen near to that region. The energy band gap and Urbach energies were also calculated as 3.16ev and 0.11364ev using Tauc plot and Urbach energy plots respectively. The synthesis method demonstrated simplicity and scalability, suggesting its potential for large-scale production in various applications.

Introduction

I. INTRODUCTION

Recent researches in the area of nanotechnology are to prepare properly and highly ordered small nanoparticles[1]. This nanoparticle employs application in various fields of science and technology. Nanoparticles due to their high surface to volume ratio differs in their electronic, optical, morphological, structural and many more properties from their bulk states. The variation of this properties has led to formation of nanoparticles for various applications. ZnO being one such material has gained significant interest due to its distinct nature of being n-type semiconductor with wide and direct energy band gap of nearly 3.37ev and high excitations energy of nearly 60meV at room temperature[2]. Basically, ZnO is white odorless solid having molecular weight of 81.36gm/mole with wurtzite crystal structure. Refractive index of nearly 2.0041 is seen whereas density is found to be 5.606gm/cm3  with melting point of 1975oc . ZnO have two crystal structures hexagonal wurtzite and cubic zinc blende. Wurtzite being more stable is prepared mostly in environmental conditions[3]. ZnO possess excellent chemical stability and due to different chemical and physical properties arising due to dependency on morphology of structure various techniques such as solgel method, microemulsion, spray pyrolysis, ultrasonic, microwave, chemical vapor deposition, hydrothermal and precipitation methods have been employed for preparation ZnO nanoparticles[4][5][6][7]. ZnO have found remarkable applications in semiconductor devices, piezoelectric sensors, gas sensors, luminescent materials, magnetic materials, catalyst and so on. As ZnO has high thermal conductivity, high binding energy, high refractive index it is used in medicine, solar cells, rubbers and as antibacterial in foods as well

II. SYNTHESIS

 In this work ZnO nanoparticle have been prepared using co-precipitation method. (0.4) M of 1.122gm Potassium hydroxide was added to a beaker containing 50 ml of distilled water. In another beaker 0.2 M of 2.97gm of zinc nitrate was added to 50 ml of distilled water. Both the solution was mixed and stirred for 2 hours continuously. This continuous stirring resulted in the formation of white suspension which represented formation of ZnO Nano particles in precipitate form. The obtained precipitate was washed s firstly with 100% alcohol once and followed by distilled water three times. The product was then filtered using filter paper and were dried for 3 hours at 200o.C This dried sample were then finely crushed in mortal pester to obtain ZnO Nanoparticles.

Conclusion

In the present work, zinc nitrate and KOH precursors were used to synthesize ZnO nanoparticle by co- precipitation method. The particles were then analyzed using XRD, FTIR, and-UV-VIS optical absorption spectroscopy XRD verified the development of ZnO’s wurtzite structure which has crystalline size of 48.14 nm corresponding to maximum peak at ?36.22?^o. The FTIR spectra provided additional confirmation of the structural characteristics of nanoparticles and confirmation of ZnO Nanoparticles. FTIR spectra were also used to predict different functional groups showing prominent peak at 519.84 ?cm?^(-1). From UV-Visible spectra absorption peak was obtained around 360nm whereas energy band gap and Urbach energies were also calculated as 3.16ev and 0.11364ev respectively. According to the result, the manufacturing procedure used in this work was straightforward and inexpensive.

References

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Copyright

Copyright © 2024 Gunjan E. Yenorkar, Lukesh D. Giradkar, Arpit D. Wagh, S. T. Bahade. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.