Augmented band gap tunability in indium-doped zinc sulfide nanocrystals

Abstract

Indium doping in ZnS nanocrystals heavily affects the band gap beyond quantum confinement effect with unprecedented tunability in the UVA/UVB range.

Significant Enhancement of Antimicrobial Activity in Oxygen-Deficient Zinc Oxide Nanowires

“…In fact, both doping and off-stoichiometric compositions in inorganic nanomaterials have been widely adopted in order to tune their properties and improve device performances. 26,27,28,29 In particular, oxygen vacancies in metal oxides have been extensively studied and recently exploited to harness enhanced optical, electrical, electrochemical and catalytic properties in the oxygen-deficient materials compared to the stoichiometric oxide counterparts. 21,30 ,31, 32 ,33 In this work, we show the combined effect of surface morphology and oxygen deficiency in the antimicrobial activity of zinc oxide (ZnO) nanostructures against both bacterial and fungal species.…”

Continuous Growth Synthesis of Zinc Oxide Nanocrystals with Tunable Size and Doping

“…6,7,8,9,10 Among these, doped metal oxides have attracted increasing interest, due to the thermal and chemical stability of metal oxides, as well as the enhanced optical, electrical and magnetic properties that may be imparted to the NCs when appropriately doped. 11,12,13,14,15 One of the main area of research for doped metal oxides is the synthesis of degenerately (aliovalently) doped wide band gap oxides, for use as transparent electrodes in optoelectronic devices including photovoltaics, light emitting diodes (LEDs) and electrochromics, but also as IR active materials for catalysis and sensing. 16,17,18,19 The colloidal synthesis of doped metal oxide NCs has been traditionally achieved using hot injection methods, which rely on the swift injection of one or more precursors into a solution containing hot solvents and/or surface ligands to trigger the nucleation of NCs.…”

Fluorine-Doped Tin Oxide Colloidal Nanocrystals

“…This peak is due to defect-related emission, including defects such as oxygen vacancies, tin interstitials and partially reduced tin (Sn 2+ at Sn 4+ sites), which create additional levels within the SnO 2 band gap [28,32,33]. This phenomenon is also commonly observed in other un-passivated quantum dots such as ZnO, ZnS and CdS [34][35][36]. Interestingly, the presence of fluorine dopants drastically decreases the intensity of this defect band, as shown in the inset of Figure 3b, where the areal (integrated) ratio between the excitonic peak and the defect peak is plotted as a function of fluorine doping.…”

“…This ratio increases almost three-fold from~0.18 for the undoped sample to~0.49 for the FTO20 sample, showing the inverse relationship between the two peaks with the addition of fluorine. It is important to note that, while dopants can act as defects and cause an increase in defect-related emissions, they can also act as luminescence quenchers through non-radiative mechanisms, which is assumed to be the case of fluorine within SnO 2 [36,37]. Notably, our FTO NCs can also be excited below the band gap, as shown in Figure 3c; following excitation at 330 nm (3.75 eV), all samples are seen to emit in the blue spectral region, again with the undoped SnO2 NCs being much brighter than the FTO NCs.…”