Francesca Caldara
Defect-assisted photoluminescence in hexagonal boron nitride nanosheets
Carlo Maria Carbonaro;Luca Malfatti;Maria Francesca Casula;Pier Carlo Ricci;
2020-01-01
Abstract
The development of functional optoelectronic applications based on hexagonal boron nitride nanosheets (h-BNNs) relies on controlling the structural defects. The fluorescent emission, in particular, has been observed to depend on vacancies and substitutional defects. In the present work, few-layerh-BNNs have been obtained by sonication-assisted liquid-phase exfoliation of their bulk counterpart. The as-prepared samples exhibit a weak fluorescent emission in the visible range, centred around 400 nm. Tailored defects have been introduced by oxidation in air at different temperatures. A significant increase in the fluorescent emission of the oxidatedh-BNNs has been observed with maximum emissive intensity for the samples treated at 300 degrees C. A further increase in temperatures (>300 degrees C) determines a quenching of the fluorescence. We investigated, by means of detailed microscopic and spectroscopic analysis, the relationship between the optical properties and defects ofh-BNNs. The investigation of the optical properties as a function of treatment temperature highlights the critical role of hydroxyl groups created by the oxidation process. Onlyh-BN exfoliated in water allows introducing OH groups with consequent enhancement of fluorescence emission. Quantum chemical calculations support the experimental findings.File | Dimensione | Formato | |
---|---|---|---|
128_20_Ren_2DMater 7 045023.pdf Solo gestori archivio
Tipologia: versione editoriale
Dimensione 3.34 MB
Formato Adobe PDF
|
3.34 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
2DM_Innocenzi_revised version_2020.pdf accesso aperto
Tipologia: versione post-print
Dimensione 2 MB
Formato Adobe PDF
|
2 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.