Photoluminescence studies of silver-exchanged cadmium selenide crystals: modification of a chemical sensor for aniline derivatives by heterojunction formation

Leung, Larry K.; Komplin, Norma J.; Ellis, Arthur B.; Tabatabaie, Ned

doi:10.1021/j100168a039

Cited by 38 publications

(30 citation statements)

References 5 publications

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“…Take suldes as an example, as shown in Table 1, the pK sp value of CdS is obviously lower than that of HgS, CuS, Ag 2 S and PbS, giving rise to a potential cation-exchange reaction on the surface of QDs. 32 As a result, surface defects are generated, leading to a nonradiative recombination of the excitons and uorescence quenching. Chemical exchange in bulk solids is limited due to the high activation energy required for the diffusion of atoms in the material.…”

Section: Qds As Metal Ion Probesmentioning

confidence: 99%

Semicondutor quantum dots-based metal ion probes

et al. 2014

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Semiconductor quantum dots (QDs) exhibit unique optical and photophysical properties that offer significant advantages over organic dyes as optical labels for chemo/bio-sensing. This review addresses the methods for metal ion detection with QDs, including photoluminescent, electrochemiluminescent, photoelectrochemical, and electrochemical approaches. The main mechanisms of direct interaction between QDs and metal ions which lead to photoluminescence being either off or on, are discussed in detail. These direct interactions provide great opportunities for developing simple yet effect metal ion probes. Different methods to design the chemically-modified QD hybrid structures through anchoring metal ion-specific groups onto the surface of QDs are summarized. Due to the spatial separation of the luminescence center and analyte recognition sites, these chemically-modified QDs offer greatly improved sensitivity and selectivity for metal ions. Several interesting applications of QD-based metal ion probes are presented, with specific emphasis on cellular probes, coding probes and sensing with logic gate operations.

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Section: Qds As Metal Ion Probesmentioning

confidence: 99%

Semicondutor quantum dots-based metal ion probes

et al. 2014

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“…The CdSe-Ag 2 Se interface in contrast is an abrupt n-n heterojunction which had a limited effect on the PL intensity as observed in previous studies. 39 The X-ray diffractograms of CdSe nanorods after reaction with AgNO 3 revealed the presence of Ag (111), ( 200) and ( 220) peaks (Fig. 3), confirming the presence of fcc Ag with a lattice parameter estimated to be 4.08…”

Section: Resultsmentioning

confidence: 57%

“…However, since the energy differences between the different chemical states of Ag were <0.5 eV, formation of Ag compounds could not be ruled out entirely solely depending on XPS. 39 However, in combination with HRTEM, UV-Vis, and XRD, the characterizations were indicative of metallic Ag tips on rods instead of Ag 2 X (X ¼ S, Se) 41 suggesting the phase transfer of Ag + ions and their reduction by DMP occurred faster than cation exchange processes. 42 FTIR analyses were also carried out on CdSe rods capped with ligands (Fig.…”

Section: Resultsmentioning

confidence: 99%

Silver tip formation on colloidal CdSe nanorods by a facile phase transfer protocol

Bala¹,

Sanyal²,

Singh³

et al. 2011

J. Mater. Chem.

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A facile phase transfer procedure is described for the formation of uniform silver metal tips on II -VI semiconductor nanorods. Judicious choice of a functional ligand, dimethyl phenol (DMP), which binds to the semiconductor rod in the organic phase enables the transfer of metal ions from the aqueous phase and their reduction onto the nanorod. The metal tips initially from as 10 random sub< 2nm particles surrounding the nanorod which ripen to dual tips at the nanorod ends. The nanorod hybrids can be assembled into perpendicularly aligned arrays by simple solvent evaporation. The hybrid nanostructu res are characterised by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), photoluminescence (PL), ultraviolet-visible spectroscopy (UV-vis) and X-ray photoelectron spectroscopy (XPS). A detailed FTIR analysis is also carried out to predict the role of the ligands in the tipping procedure.

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“…Hg 2+ ) since the K sp values of the resulting crystal (HgS) are higher than CdS. 114 Mild cation exchange method was also reported for Mn-doped ZnSe QDs in the detection of Cd 2+ and Hg 2+ ions. 115 …”

Section: Fluorescence Detection Mechanismsmentioning

confidence: 99%