Dielectric Properties of Cr³⁺ Doped Al₂O₃ of a Hierarchical Nanostructure Synthesized Using a Highly Porous Precursor of Tubular AlO(OH)⋅αH₂O Fibers

Abstract:

Herein, we have developed a Cr³⁺ doped Al₂O₃ of a hierarchical nanostructure by a simple two-step synthesis. A pure AlO(OH)⋅αH₂O, as synthesized in forms of small tubular fibers by hydrolysis of Al-metal sheets, is easily doped with selective Cr³⁺ dosages up to 2.0 mol% using an aqueous CrO₃. As-synthesized samples exhibit XRD of a single phase Cr³⁺: Al₂O₃ of a rhombohedral crystal structure. Average pore-volume is decreased as 98.1, 89.8, and 61.5 cm³-g^-1 in the 0.5, 1.0 and 2.0 % Cr% doped samples, with average pore radius of 1.70, 2.17 and 1.90 nm, respectively, as measure from BET specific surface area. Local Al-O vibrations exhibit IR bands of 400 to 1200 cm^-1 intrinsic of oxygen polygons. At room temperature, a duly tailored dielectric permittivity of 480 is obtained in a 2.0 mol% Cr³⁺:Al₂O₃ and that is enhanced progressively on heating it over 25 to 300 °C, showing a value 6700 at 300 °C in phonon induced dynamics of charge carriers, useful for solid-state electronics.

• Periodical: Materials Science Forum (Volume 1019)
• Pages: 135-141
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.1019.135
• Online since: January 2021
• Authors: Surendra Jangu*, Sanjeev Kumar Sharma, Amit Kumar Sudhansu, Shanker Ram
• Keywords: Dielectric Permittivity, Nanostructure, Solid-State Electronics, Tubular Fibers

References

[1] R.K. Koninti, A. Sengupta, K. Gavvala, N. Ballav and P. Hazra, Loading of an anti-cancer drug onto graphene oxide and subsequent release to DNA/RNA: a direct optical detection, Nanoscale. 6 (5) (2014) 2937-2944.

DOI: 10.1039/c3nr06081k

[2] L. Wang, C. Hu and L. Shao, The antimicrobial activity of nanoparticles: present situation and prospects for the future, Int. J. Nanomed. 12 (2017) 1227-1249.

DOI: 10.2147/ijn.s121956

[3] L.R. Khot, S. Sankaran, J. M. Maja, R. Ehsani and E.W. Schuster, Applications of nanomaterials in agricultural production and crop protection: a review, Crop Prot. 35 (2012) 64-70.

DOI: 10.1016/j.cropro.2012.01.007

[4] W. Yang, P. Wan, H. Meng, J. Hu and L. Feng, Supersaturation-controlled synthesis of diverse In2O3 morphologies and their shape-dependent sensing performance, CrystEngComm.17 (2015) 2989-2995.

DOI: 10.1039/c4ce02535k

[5] M.H. Braga, N.S. Grundish, A.J. Murchison and J.B. Goodenough, Alternative strategy for a safe rechargeable battery, Energy Environ. Sci. 10 (1) (2017) 331-336.

DOI: 10.1039/c6ee02888h

[6] S. Jangu, B. K. Satpathy, C. Jacob and D. Pradhan, Microwave-hydrothermally synthesized MnO2nano-rods/flakes for high-performance electrochemical supercapacitors, AIP Conf. Proc. 2220(1) (2020) 020128.

DOI: 10.1063/5.0001619

[7] V.S. Benitha, K. Jeyasubramanian, R. Mala, G.S. Hikku and R.R. Kumar, New sol–gel synthesis of NiO antibacterial nano-pigment and its application as healthcare coating, J. Coat. Technol. Res. 16(1) (2019) 59-70.

DOI: 10.1007/s11998-018-0100-5

[8] Z. Liu, J. Xu, D. Chen and G. Shen, Flexible electronics based on inorganic nanowires, Chem. Soc. Rev. 44 (1) (2015) 161-192.

DOI: 10.1039/c4cs00116h

[9] T.S. Rodrigues, A.G.M.da Silva and P.H.C. Camargo, Nanocatalysis by noble metal nanoparticles: controlled synthesis for the optimization and understanding of activities, J. Mater. Chem. A 7 (2019) 5857-5874.

DOI: 10.1039/c9ta00074g

[10] B. Tiwari, S. Sharma, S. Ram and P. Banerji, Synthesis of broad band violet–blue light-emitting core–shell Cr3+: C–CaIn, J. Nanosci. Nanotechnol. 19 (2019) 1-5.

DOI: 10.1166/jnn.2019.16596

[11] J. Chang, Y. Choi and J.D. Lee, Electronic structure of chromium aluminum oxide, Adv. Quantum Chem. 42 (2003) 163-173.

[12] S.K. Sharma, P.V. Rajeswari, B. Tiwari and S. Ram, Hydrothermal synthesis of LiMnPO4-C(sp2) hybrids, conductive channels, and enhanced dielectric permittivity: a modulated ionic conductor, Ionics.23 (2017) 43-53.

DOI: 10.1007/s11581-016-1800-4

[13] S. Ram and S. Rana, Synthesis of porous Al2O3 ceramic clusters by surface hydrolysis of a thin Al-metal plate in water, Mater. Sci. Eng. A. 304 (2001) 790–795.

DOI: 10.1016/s0921-5093(00)01570-7

[14] K.S.W. Sing, D.H. Everett, R.A.W. Haul, L. Moscou, R.A. Pierotti, J. Rouquérol and T. Siemieniewska, International union of pure commission on colloid and surface chemistry including catalysis* reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity, Pure Appl. Chem. 57 (1985) 603-619.

DOI: 10.1515/iupac.57.0013

[15] S. Rana and S. Ram, X-ray diffraction and IR spectrum for activated surface hydrolysis of Al metal into AlO(OH)·αH2O nanocrystals in a new monoclinic crystal structure, J. Solid State Chem. 157 (2001) 40-49.

DOI: 10.1006/jssc.2000.9034

[16] D.S. Saini, A. Ghosh, S. Tripathy, S.K. Sharma, A. Kumar and D. Bhattacharya, Improved conductivity of spark plasma sintered Ho-substituted BaZrO3 electrolyte ceramics for IT-SOFCs, ACS Appl. Energy Mater. 1 (2018) 3469-3478.

DOI: 10.1021/acsaem.8b00655

[17] T. Ghosh, S.K. Sharma and D. Pradhan, Giant dielectric constant and superior photovoltaic property of the mechanochemically synthesized stable CH3NH3PbBr3 in a hole transporter-free solar cell, ACS Sustainable Chem. Eng. 8(3) (2020) 1445-1454.

DOI: 10.1021/acssuschemeng.9b05678.s001