ZnO nanoparticles (NPs) synthesized by pulsed laser ablation (PLAL) of a zinc plate in deionized water were investigated by time-resolved photoluminescence (PL) and complementary techniques (TEM, AFM, μRaman). HRTEM images show that PLAL produces crystalline ZnO NPs in wurtzite structure with a slightly distorted lattice parameter a. Consistently, optical spectra show the typical absorption edge of wurtzite ZnO (Eg = 3.38 eV) and the related excitonic PL peaked at 3.32 eV with a subnanosecond lifetime. ZnO NPs display a further PL peaking at 2.2 eV related to defects, which shows a power law decay kinetics. Thermal annealing in O2 and in a He atmosphere produces a reduction of the A1(LO) Raman mode at 565 cm-1 associated with oxygen vacancies, accompanied by a decrease of defect-related emission at 2.2 eV. Based on our experimental results the emission at 2.2 eV is proposed to originate from a photo-generated hole in the valence band recombining with an electron deeply trapped in a singly ionized oxygen vacancy. This investigation clarifies important aspects of the photophysics of ZnO NPs and indicates that ZnO emission can be controlled by thermal annealing, which is important in view of optoelectronic applications.

Camarda, P., Messina, F., Vaccaro, L., Agnello, S., Buscarino, G., Schneider, R., et al. (2016). Luminescence mechanisms of defective ZnO nanoparticles. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 18(24), 16237-16244 [10.1039/c6cp01513a].

Luminescence mechanisms of defective ZnO nanoparticles

LORENZI, ROBERTO;
2016

Abstract

ZnO nanoparticles (NPs) synthesized by pulsed laser ablation (PLAL) of a zinc plate in deionized water were investigated by time-resolved photoluminescence (PL) and complementary techniques (TEM, AFM, μRaman). HRTEM images show that PLAL produces crystalline ZnO NPs in wurtzite structure with a slightly distorted lattice parameter a. Consistently, optical spectra show the typical absorption edge of wurtzite ZnO (Eg = 3.38 eV) and the related excitonic PL peaked at 3.32 eV with a subnanosecond lifetime. ZnO NPs display a further PL peaking at 2.2 eV related to defects, which shows a power law decay kinetics. Thermal annealing in O2 and in a He atmosphere produces a reduction of the A1(LO) Raman mode at 565 cm-1 associated with oxygen vacancies, accompanied by a decrease of defect-related emission at 2.2 eV. Based on our experimental results the emission at 2.2 eV is proposed to originate from a photo-generated hole in the valence band recombining with an electron deeply trapped in a singly ionized oxygen vacancy. This investigation clarifies important aspects of the photophysics of ZnO NPs and indicates that ZnO emission can be controlled by thermal annealing, which is important in view of optoelectronic applications.
Articolo in rivista - Articolo scientifico
oxide nanoparticle; TEM; time resolved photoluminescence; Raman; ZnO;
English
2016
18
24
16237
16244
partially_open
Camarda, P., Messina, F., Vaccaro, L., Agnello, S., Buscarino, G., Schneider, R., et al. (2016). Luminescence mechanisms of defective ZnO nanoparticles. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 18(24), 16237-16244 [10.1039/c6cp01513a].
File in questo prodotto:
File Dimensione Formato  
Camarda-2016-Phys Chem Chem Phys-VoR.pdf

Solo gestori archivio

Descrizione: Article
Tipologia di allegato: Publisher’s Version (Version of Record, VoR)
Dimensione 2.76 MB
Formato Adobe PDF
2.76 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Camarda-2016-Phys Chem Chem Phys-AAM.pdf

accesso aperto

Descrizione: Article
Tipologia di allegato: Author’s Accepted Manuscript, AAM (Post-print)
Dimensione 495.69 kB
Formato Adobe PDF
495.69 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/119049
Citazioni
  • Scopus 87
  • ???jsp.display-item.citation.isi??? 78
Social impact