Fluorescence quantum efficiency of CdSe/ZnS quantum dots functionalized with amine or carboxyl groups

Rapid detection of vegetable cooking oils adulterated with inedible used oil using fluorescence quenching method with aqueous CTAB-coated quantum dots

“…2A displays the fluorescence intensity of the modified CTAB-coated CdSe/ZnS QDs in water phase only decreased a little (less than 10%) in comparison with the original QDs in hexane. This was due to the fact that both the fluorescence quantum efficiency and the absolute non-radiative quantum efficiency were dependent on the core size of the CdSe/ZnS QDs, so that the functionalization with amine groups would not significantly change the high quantum efficiency values [41,42]. As shown in Fig.…”

Optical characterization of core–shell quantum dots embedded in synthetic saliva: Temporal dynamics

“…Ideally, this process should reduce defects present on the surface of the QDs, favoring the excitonic transition, and consequently increase the fluorescence. However, our previous work [6] shows that nonfunctionalized CdSe/ZnS QDs in aqueous solutions present slightly higher  value than the same functionalized QDs with amine or carboxyl groups. The addition of functional groups can increase the possibility of damaging the surface due to imperfect grafting of ligands and/or incomplete coverage [50,51].…”

“…As the QD size decreases, the energy spacing of its atomic-like states increases beyond the available thermal energy, which inhibits the thermally induced depopulation of the lowest electronic states [11]. The  value obtained for the synthesized ultrasmall CdSe/CdS QDs functionalized with hydroxyl groups is higher than the values obtained for CdSe/ZnS QDs functionalized with amine or carboxyl groups [6] and for magic-sized CdSe/CdS QDs [49]. The increased value of  for functionalized ultrasmall CdSe/CdS can be understood by decrease of QD size and quantum confinement effects [47,48].…”

“…These materials present properties of the semiconductor family, but unlike most semiconductors, they have characteristic absorption and emission spectra [2]. The optical properties of the QDs can be modified simply by varying the particle size [1], and QDs synthesized in aqueous solutions [3,4] with appropriate functionalizations [5,6] are required for biomedical applications. Nanoparticles are very chemically flexible in aqueous phases; this flexibility makes it possible to incorporate a wide variety of biomolecules, such as proteins, peptides and DNA [7].…”

Caracterização termo-óptica de resinas dopadas com nanocristais semicondutores: efeitos de incidência de radiação ionizante

“…Neste item, serão analisados o parâmetro θ normalizado pela potência absorvida, Pabs, para os dois conjuntos de resinas preparadas (em função da concentração e do tamanho dos PQs). Para as amostras líquidas de PQs com diferentes tamanhos realizadas já pelo nosso grupo de pesquisa não foram observados variação dos valores de difusividade térmica [8,51]. Isso pode ser entendido, possivelmente pela baixa concentração das soluções avaliadas ou estudadas nas referências.…”