IMF 2023

Electric field induced and ferroelectric photovoltaic effects on the modified BaTiO3

Murugavel Pattukkannu 1 Shanmuka Priya K 1 Subhajit Pal 1 Jatin Kumar Bidika 1 Murali D 2 Birabar Ranjit Kumar Nanda 1
1Functional Oxides Research Group, Department of Physics, Indian Institute of Technology-Madras, Chennai, Tamil Nadu, India
2Department of Science, Indian Institute of Technology, Design and Manufacturing, Kurnool, Kurnool, Andhra Pradesh, India

Understanding the structure – property relations plays a crucial role in engineering the novel materials towards their enhanced application potentials. In recent times, the ferroelectric photovoltaic effect is gaining importance in the field of energy harvesting.1,2 This bulk photovoltaic phenomenon has strong correlation with structural preference and the related delocalized orbital states at the band edges.3 In this work, we have probed the role of electric field induced structural phase transformation along with the delocalized electronic orbital states on the photovoltaic performance of Bi and Li co-doped BaTiO3 system. The X-ray diffraction studies on the Ba0.875(Bi0.5Li0.5)0.125TiO3 oxide performed before and after poling revealed a 23% increase in orthorhombic phase fraction at the cost of a tetragonal phase. Rayleigh analysis performed on the polarization data recorded under sub-coercive fields demonstrated the strong correlation between the poling-induced structural phase transformation and the field induced lattice deformation. The Raman studies displayed the suppression of the Bi-O bond length (A2g mode) upon electric poling. The field-induced orientational defect resulted in an asymmetry in the polarisation hysteresis loop with an internal bias electric field of 8 V/cm. Importantly, the poling induced large internal bias field of the sample facilitates the large photovoltaic response with an open-circuit voltage of 12 V. The partial density of states based on the density functional theory on the respective tetragonal and orthorhombic phases before and after poling ascertained the role of orbital delocalization at the band edges on the enhanced photovoltaic performance parameters of the ferroelectric system.

References:

1. A.Polman, M.Knight, E.C.Garnett, B.Ehrler, and W.C.Sinke, Science 352, 307 (2016).

2. S.Pal, N.V.Sarath, K.Shanmuga Priya, and P.Murugavel, J. Phys. D. Appl. Phys. 55 283001 (2022).

3. S. Pal, A.B.Swain, P. P.Biswas, D.Murali, A. Pal, B.R.K.Nanda, and P.Murugavel, Sci. Rep. 8, 8005 (2018).





IMF 2023




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