Exploring Electronic and Structural Properties of Titanium-Doped Chlorapatite: A Theoretical and Experimental Investigation

Abstract

The apatite family stands as a pivotal class of inorganic compounds with diverse elemental components, playing a crucial role in biological, environmental, and geological contexts. Among these, chlorapatite (ClAp) emerges as a significant member, featuring a hexagonal structure with the space group P63/m. In this theoretical study, we delve into the unexplored realm of Ti-doped ClAp structures, investigating their electronic and structural characteristics for the first time. Motivated by the potential impact of titanium (Ti) doping on electronic and optical properties, we employ density functional theory (DFT) principles to perform band structure calculations. The electronic band structure is explored comprehensively, shedding light on the energy distribution for electrons as a function of momentum. Our calculations reveal that un-doped ClAp exhibits an insulating nature, as indicated by a calculated band gap of approximately 4.947 eV. The theoretical volume parameter closely matches experimental observations, validating the reliability of our computational model. Introducing Ti as a dopant in 1.2TiClAp results in a discernible increase in the band gap to approximately 5.339 eV. The theoretical volume parameter exhibits excellent agreement with experimental data, emphasizing the precision of our calculations. For 2.4TiClAp, the band gap remains stable at around 5.344 eV, while the theoretical volume parameter stands at 0.5260 nm3. Our systematic exploration of Ti-doped ClAp underscores the tunability of electronic properties, signifying potential applications across diverse fields. The reliability of theoretical calculations is further affirmed by the consistent alignment with experimental parameters. These findings contribute significantly to our fundamental understanding of Ti-doped ClAp, providing crucial insights for material design and optimization. Ongoing collaborative efforts between theoretical and experimental approaches are essential for a comprehensive assessment of these complex materials.

Keywords

• Chlorapatite
• Ti-doping
• Density functional theory (DFT)
• Bandgap

References

1. A. Durugkar, S. Tamboli, N.S. Dhoble, S.J. Dhoble, “Novel photoluminescence properties of Eu3+ doped chlorapatite phosphor synthesized via sol-gel method” Materials Research Bulletin, 97, 466-472, 2018. https://doi.org/10.1016/j.materresbull.2017.09.043.
2. H. Jena, B.K. Maji, R. Asuvathraman, K.V.G. Kutty, “Synthesis and thermal characterization of glass bonded Ca-chlorapatite matrices for pyrochemical chloride waste immobilization” Journal of Non-Crystalline Solids, 358, 1681-1686, 2012. https://doi.org/10.1016/j.jnoncrysol.2012.05.002.
3. H. Jena, B.K. Maji, R. Asuvathraman, K.V.G. Kutty, “Effect of pyrochemical chloride waste loading on thermo-physical properties of borosilicate glass bonded Sr-chlorapatite composites” Materials Chemistry and Physics, 162, 188-196, 2015. http://dx.doi.org/10.1016/j.matchemphys.2015.05.057.
4. N.J. Flora, K.W. Hamilton, R.W. Schaeffer, C.H. Yoder, “A Comparative Study of the Synthesis of Calcium, Strontium, Barium, Cadmium, and Lead Apatites in Aqueous Solution” Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, 34(3), 503-521, 2004. https://doi.org/10.1081/SIM-120030437.
5. B.K. Maji, H. Jena, R.V. Krishnan, R. Asuvathraman, K. Ananthasivan, K.V.G. Kutty, “Comparison of thermal expansion and heat capacity properties of various borosilicate glass-bonded strontium chlorapatite composites loaded with simulated pyrochemical waste” Journal of Thermal Analysis and Calorimetry, 119, 1825-1831, 2015. https://doi.org/10.1007/s10973-014-4322-1.
6. H. Jena, R.V. Krishnan, R. Asuvathraman, K. Nagarajan, K.V.G. Kutty, “Thermal expansion and heat capacity measurements on Ba10−x Cs x (PO4)6Cl2−δ, (x=0, 0.5) chlorapatites synthesized by sonochemical process” Journal of Thermal Analysis and Calorimetry, 106, 875-879, 2011. https://doi.org/10.1007/s10973-011-1715-2.
7. M.H. Hwang, Y.J. Kim, S.H. Jung, S.H. Han, “Preparation and Luminescent Characterization of M5(PO4)3Cl (M: Sr, Ca) Chlorapatites by a Solid-state Reaction Method” Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry, 38(3), 307-311, 2008. https://www.tandfonline.com/doi/full/10.1080/15533170802023528.
8. M. Ganjali, S. Pourhashem, M. Mozafari, “The effect of heat-treatment on the structural characteristics of nanocrystalline chlorapatite particles synthesized via an in situ wet-chemical route” Ceramics International, 41(10), 13100-13104, 2015, https://doi.org/10.1016/j.ceramint.2015.07.020.

9. X. Xu, X. Yu, L. Mao, S.P. Yang, Z. Peng, “Preparation and photoluminescence of Bi3+-doped strontium chlorapatite nano-phosphor” Materials Letters, 58(29), 3665-3668, 2004, https://doi.org/10.1016/j.matlet.2004.04.037.
10. M. Nabiyouni, H. Zhou, S.B. Bhaduri, “Microwave assisted solution combustion synthesis (MASCS) of europium (Eu) doped chlorapatite nanowhiskers” Materials Letters, 108, 54-57, 2013, https://doi.org/10.1016/j.matlet.2013.06.089.
11. R. Pazik, J.M. Nedelec, R.J. Wiglusz, “Preferential site substitution of Eu3+ ions in Ca10(PO4)6Cl2 nanoparticles obtained using a microwave stimulated wet chemistry technique” CrystEngComm, 16, 5308-5318, 2014, https://doi.org/10.1039/C4CE00197D.
12. C.H. Wang, D.Y. Gui, R. Qin, F.L. Yang, X.P. Jing, G.S. Tian, W. Zhu, “Site and local structure of activator Eu2+ in phosphor Ca10−x(PO4)6Cl2:xEu2+” Journal of Solid State Chemistry, 206, 69-74, 2013, https://doi.org/10.1016/j.jssc.2013.07.035.
13. B. Nasiri-Tabrizi, W.J. Basirun, B. Pingguan-Murphy, “Mechanochemical preparation and structural characterization of Ta-doped chlorapatite nanopowders” Progress in Natural Science, 26(6), 546-554, 2016, https://doi.org/10.1016/j.pnsc.2016.11.010.
14. B. Nasiri-Tabrizi, E. Zalnezhad, B. Pingguan-Murphy, W.J. Basirun, A.M.S. Hamouda, S. Baradaran, “Structural and morphological study of mechanochemically synthesized crystalline nanoneedles of Zr-doped carbonated chlorapatite” Materials Letters, 149, 100-104, 2015, https://doi.org/10.1016/j.matlet.2015.02.125.
15. L. Wang, K. Liu, J. Wang, L. Zhao, Y. Xu, R. Zhou, L. Chen, B. Qu, “Defects levels and VUV/UV luminescence of Ce3+ and Eu3+ doped chlorapatite phosphors M5(PO4)3Cl (M = Ca, Sr, Ba)” Optical Materials, 107, 110014, 2020, https://doi.org/10.1016/j.optmat.2020.110014.
16. Z. Zhang, J. Wang, M. Zhang, Q. Zhang, Q. Su, “The energy transfer from Eu2+ to Tb3+ in calcium chlorapatite phosphor and its potential application in LEDs” Applied Physics B, 91, 529-537, 2008, https://doi.org/10.1007/s00340-008-3035-1.
17. Y.K. Kim, M. Lee, H.S. Yang, M.G. Ha, K.S. Hong, “Optical characteristics of the rare-earth-ions-doped calcium chlorapatite phosphors prepared by using the solid–state reaction method” Current Applied Physics, 16(3), 357-360, 2016, https://doi.org/10.1016/j.cap.2015.12.016.
18. A. Fahami, G.W. Beall, “Mechanosynthesis of carbonate doped chlorapatite–ZnO nanocomposite with negative zeta potential” Ceramics International, 41(9), 12323-12330, 2015, https://doi.org/10.1016/j.ceramint.2015.06.061.
19. S.J. Clark, M.D. Segall, C.J. Pickard, P.J. Hasnip, M.I.J. Probert, K. Refson, M.C. Payne, “First Principles Methods Using CASTEP” Zeitschrift für Kristallographie-Crystalline Materials, 220, 567-570, 2005, https://doi.org/10.1524/zkri.220.5.567.65075.
20. K. Momma, F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data” Journal of Applied Crystallography, 44, 1272-1276, 2011, http://dx.doi.org/10.1107/S0021889811038970.
21. C.C. Ribeiro, I. Gibson, M.A. Barbosa, “The uptake of titanium ions by hydroxyapatite particles-structural changes and possible mechanisms” Biomaterials, 27(9), 1749-1761, 2006, https://doi.org/10.1016/j.biomaterials.2005.09.043.
22. B.D. Cullity, “Elements of X-ray diffraction” Addison-Wesley Publishing Company, Massachusetts, 1978
23. M.E. Fleet, X. Liu, “Type A–B carbonate chlorapatite synthesized at high pressure” Journal of Solid State Chemistry, 181(9), 2494-2500, 2008, https://doi.org/10.1016/j.jssc.2008.06.016.
24. L.D.A. Cavalcante, L.S. Ribeiro, M.L. Takeno, P.T.P. Aum, Y.K.P.G. Aum, J.C.S. Andrade, “Chlorapatite derived from fish scales” Materials, 13(5), 1129, 2020, https://doi.org/10.3390/ma13051129.
25. A. Fahami, G.W. Beall, T. Betancourt, “Synthesis, bioactivity and zeta potential investigations of chlorine and fluorine substituted hydroxyapatite” Materials Science and Engineering: C, 59, 78-85, 2016, https://doi.org/10.1016/j.msec.2015.10.002.