Impact of Dopants on the Electrical and Optical Properties of Hydroxyapatite

Abstract

This chapter deals with the effect of alternating electrical current on hydroxyapatite [HAp, Ca10(PO4)6(OH)2] and doped HAp along with their optical response and the processes involved. The dielectric constant, permittivity and ac conductivity were analyzed to have an insight into the surface charge polarization phenomenon. Further, the magnitude and the polarity of the surface charges, microstructure, and phases also play significant role in the cell proliferation and growth on the implants. Besides, the mechanism behind the electrical properties and the healing of bone fracture are discussed. The influence of various dopants on the optical properties of HAp viz., absorbance, transmission, band gaps and defects energy levels are analyzed along with the photoluminescence and excitation independent emission. In the future outlook, the analysis of effect of doping is summarized and its impact on the next generation biomaterials are elucidated.

Synthesis of different types of nano-hydroxyapatites for efficient photocatalytic degradation of textile dye (Congo red): a crystallographic characterization

“…Direct band gap materials are preferred due to their prolonged lifetime of charge carriers, while indirect band gap materials may have advantages, but their direct band gap is inherent to HAp. 61–64…”

“…Direct band gap materials are preferred due to their prolonged lifetime of charge carriers, while indirect band gap materials may have advantages, but their direct band gap is inherent to HAp. [61][62][63][64] Photocatalytic agents, such as free radicals and electrons, play a crucial part in the photocatalytic deterioration of Congo red dye. These agents, coupled with holes, act as effective oxidizing agents, helping in the formation of more reactive species owing to the delayed reproduction of e − as well as h + .…”

The Effect of Doping on the Electrical and Dielectric Properties of Hydroxyapatite for Medical Applications: From Powders to Thin Films

“…This decline could be connected to the alignment o dipoles within the fabricated structures that have a tendency to position themselves in th direction of the applied electric field. Conversely, at low applied frequencies, the inferre ε1 values were relatively high, most probably due to the slow relaxation of highly oriente dipoles [2]. Additionally, the increase in CuO and HT contents also led to a rise in dipoles content, further influencing ε1 values [115].…”

“…When using high frequencies, Younes et al [115] showed that σ ac values had a continuous increase due to ions' segregation along the c-axis of the HA crystal structure [2]. When increasing the HT and CuO contents, the σ ac values increased continuously due to the increase in the number of charge carriers.…”

“…They provide essential information about the local environment, such as stability and porosity [1]. A prime example of such a biomaterial is hydroxyapatite (HA), a remarkable bioceramic belonging to the calcium phosphate family, known for its high dielectric constant [2]. Scientists have harnessed the potential of HA for medical use (including bone tissue engineering) due to its osteogenic properties, ability to form strong bonds with bone tissues, resemblance to the native apatite found in the human body, and natural occurrence in bones, teeth, cartilage, eggshells, corals, and exoskeletal tissues [3,4].…”