Induced structural defects in Ti-doped ZnO and its two-photon-excitation Conference Paper


Authors: Julca, M. A. M.; Rivera, I.; Mercado, J. S.; Sierra, H.; Perales-Pérez, O.
Editors: Parak, W. J.; Osinski, M.; Liang, X. J.
Title: Induced structural defects in Ti-doped ZnO and its two-photon-excitation
Conference Title: Colloidal Nanoparticles for Biomedical Applications XI
Abstract: ZnO is a well-known luminescent material that reacts with light to generate free radicals enabling its use in cancer treatment by Photodynamic Therapy (PDT). Unfortunately, up to know, the photo-excitation of ZnO-based materials' requires excitation with ultraviolet light, which limits their biomedical applications. In this regard, this work investigates the effect of Ti species incorporation into the lattice of ZnO nanoparticles (NPs) with the aim of improving the corresponding optical properties and enabling the two-photoexcitation with 690nm-light (near infrared light). A modified polyol-based route was used to synthesize pure and Ti-doped (9% at.) ZnO NPs. X-ray diffraction confirmed the formation of ZnO-wurtzite whereas Scanning Electron Microscopy confirmed the formation of monodispersed 100-nm NPs. Raman Spectroscopy measurements evidenced the presence of zinc interstitials (Zni) and oxygen vacancies (VO) in the host oxide strcuture. Asynthesized NPs were excited using the technique of two-photon fluorescence microscopy (TPFM). The photoluminescence (PL) spectra generated from the analysis of TPFM images revealed a high emission peak presence in the green region (555 nm) that was assigned to VO. Also, a weak but noticeable band at 420 nm was detected, which is attributed to electron transition from the shallow donor level of Zni to the valence band. These PL transitions will favor triplet states formation necessary to yield cytotoxic reactive oxygen species. Furthermore, the presence of the PL peaks confirmed the Ti-ZnO NPs capacity to be excited by 690-nm light, thus, opening new possibilities for this NPs to be used in lightinduced bio-medical applications. © 2016 SPIE.
Keywords: fluorescence; reactive oxygen species; nanoparticles; fluorescence microscopy; photons; zinc; photodynamic therapy; optical properties; x ray diffraction; defects; medical applications; zinc oxide; infrared devices; scanning electron microscopy; biomedical applications; free radicals; fluorescent microscopy; photoluminescence; colloids; pdt; ti-doped zno; two-photon fluorescent microscopy; electron transitions; optical lattices; oxygen vacancies; zinc sulfide; photodynamic therapy (pdt); photoluminescence spectrum; raman spectroscopy measurements; two-photon fluorescence microscopy
Journal Title Proceedings of SPIE
Volume: 9722
Conference Dates: 2016 Feb 13-15
Conference Location: San Francisco, CA
ISBN: 0277-786X
Publisher: SPIE  
Date Published: 2016-02-13
Start Page: 9722 1E
Language: English
DOI: 10.1117/12.2213750
PROVIDER: scopus
DOI/URL:
Notes: Conference Paper -- Conference code: 122962 -- Export Date: 1 September 2016 -- The Society of Photo-Optical Instrumentation Engineers (SPIE) -- 13 February 2016 through 15 February 2016 -- Source: Scopus
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