5TH International Congress on Technology - Engineering & Science - Kuala Lumpur - Malaysia (2018-02-01)

Structural, Optical And Electrical Properties Of Al-mn Co-doped Sno2 Nanoparticles Synthesised By Sol-gel Process

Many research works have been carried out on studying the effect of metal co-doping[1-6] on the structural, optical and magnetic properties of SnO2 nanoparticles. In the present work, Aluminium (Al) and Manganese (Mn) co-doped SnO2 nanoparticles were synthesised by Sol-gel process and their structural, optical and electrical properties were investigated extensively and reported for the first time.Sn1-x-yAlxMnyO2 nanoparticles were synthesised with Al and Mn varying in the wt% ratio( i.e. Al:Mn) as 0.0:1.0,0.5:0.5, 1.0:1.0 and 2.0:2.0. On increasing the concentration of dopants, crystallite size is found to be reduced which reveals that Al and Mn ions replace the Sn ion. Also, to meet the charge balance, formation of oxygen vacancies increases which further decreases the crystallite size. This is confirmed from the surface area analysis where the surface area of 1.0:1.0wt% ratio of Al:Mn doped sample is larger than that of 0.0:1.0 wt% Al:Mn doped sample which indicates that the dopant ions inhibit the growth of SnO2 nanoparticles. FTIR analysis confirmed the incorporation of Al and Mn atoms in the SnO2 lattice. From the impedance spectroscopic analysis, it was found that,among the co-doped samples, the 2.0:2.0wt% ratio of Al:Mn doped sample is found to have the highest room temperature dc electrical conductivity which may be due to more number of surface active sites resulting from the reduced crystallite size. The non-linear behavior observed in the thermal dependence of the conductivity of Al-Mn co-doped SnO2 nanoparticles was explained by means of the defect states which modify the band structure on increasing the concentrations of Al and Mn. The frequency exponent (“s” value) obtained by fitting Jonscher’s power law gives an understanding of the ac conducting mechanism.WhenSnO2 is doped with Al and Mn, it has an effect of reducing the permittivity (dielectric constant) to a greater extent than undoped SnO2 sample. In the frequency range from 150Hz to 7MHz,the loss factor (ɛ") is drastically reduced.The significant decrease in dielectric loss isascribed to acceptor dopants that induce oxygen vacancieswhich neutralizes the free electrons.Since the dielectric loss factor is low, significantly, tanδis less than 1 which indicates that less energy is dissipated in the Al-Mn co-doped samples. Thus the Al-Mn co-doped SnO2 nanoparticles may find application in devices where the optimum frequency range is 150Hz to 30KHz. But based on the conductivity, the undoped sample is seen to have the highest value. So a balancing condition is needed to obtain optimum dielectric loss and conductivity. Keywords: Al-Mn co-doped SnO2; BET surface area; Impedance spectroscopy; Sol-gel process; Structural study. References: [1] Ntimane N J, Rammutla K E, Mosuang T E. Effects of combinational Al and Y doping on the structural and optical properties of nanocrystalline SnO2. Indian. J. Phys. (2015); 89(7):671. [2] Venkateswara Reddy P, Venkatramana Reddy S, Sankara Reddy B. Structural and optical properties of co-doped (Fe, Al) SnO2 nanoparticles.Int. J.Chemtech. Res. (2014); 7(3):1474. [3] Venkateswara Reddy P, Venkatramana Reddy S, Sankara Reddy B, Vijayalakshmi R P. Investigation on structural and photoluminescence properties of (Co, Al) Codoped SnO2 nanoparticles.Nanosystems: Phys. Chem. Math. (2016); 7 (3):494. [4] Nilavazhagan S, Muthukumaran S. Investigation of optical and structural properties of Fe, Cu co-doped SnO2 nanoparticles. SuperlatticesMicrostruct.(2015); 83:507. [5] Aditya Sharma, MayoraVarshney, ShalendraKumar,Verma K D, Ravi Kumar. Magnetic Properties of Fe and Ni doped SnO2 Nanoparticles. Nanomater.nanotechnol. (2011); 1(1): 24. [6] Ghosh S, Mandal M, Mandal K. Effects of Fe doping and Fe-N codoping on magnetic properties of SnO2 prepared by chemical co-precipitation. J. Magn. Magn.Mater. (2011); 323:1083.
Prithivikumaran Natarajan, Sudha Periathai Ramamurthi, Pon Vengatesh Ramamurthi, Jeyakumaran Natarajan