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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Structural properties and self-activated photoluminescence emissions in hydroxyapatite with distinct particle shapes

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Author(s):
Machado, Thales R. [1] ; Sczancoski, Julio C. [1] ; Beltran-Mir, Hector [2] ; Li, Maximo S. [3] ; Andres, Juan [4] ; Cordoncillo, Eloisa [2] ; Leite, Edson [1] ; Longo, Elson [1]
Total Authors: 8
Affiliation:
[1] Univ Fed Sao Carlos, CDMF UFSCar, POB 676, BR-13565905 Sao Carlos, SP - Brazil
[2] Univ Jaume 1, QIO UJI, Castellon de La Plana 12071 - Spain
[3] Univ Sao Paulo, IFSC USP, POB 369, BR-13560970 Sao Carlos, SP - Brazil
[4] Univ Jaume 1, QFA UJI, Castellon de La Plana 12071 - Spain
Total Affiliations: 4
Document type: Journal article
Source: CERAMICS INTERNATIONAL; v. 44, n. 1, p. 236-245, JAN 2018.
Web of Science Citations: 5
Abstract

The understanding on defect-related photoluminescence (PL) properties of hydroxyapatite (HA) particles has a fundamental importance in the technological field for the development of new non-toxic biomedical and optical devices. However, the mechanisms responsible for this intrinsic PL in HA are not completely elucidated in the literature yet. In the present paper, stoichiometric and calcium-deficient HA nano- and micro-particles were synthesized by chemical precipitation. The influence of structural and morphological features on the intrinsic PL and electronic structure of this material were investigated by varying the addition rate of the phosphate precursor (0.15, 7.00 or 600.00 mL/min) and pH (4.5-5.0 or 9.5-10.0) value adopted in the precipitation. The results indicated that the structural order at long- and short-range varied with the synthesis conditions and particle shapes (rods, needles, plates, and rices). The blue and green PL emissions were attributed to defects (bulk, surface and interface) in the samples. These defects promoted the formation of additional energy levels within the band gap, as revealed by using two distinct excitation wavelengths for photoemission measurements. The energies of these wavelengths (3.54 and 2.98 eV at 350 and 415 nm, respectively) were lower than the band gap energies of HA samples (from 5.59 to 5.72 eV). A general model was proposed to explain the occurrence of self-activated PL in HA structure. (AU)

FAPESP's process: 13/11144-3 - Study, Characterization and Properties of Multifunctional Orthophosphates
Grantee:Thales Rafael Machado
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
Grantee:Elson Longo da Silva
Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC