Controlling conductivity via doping in semiconductor quantum dots is an important part of nanoparticle research. In this report, doping of CdSe quantum dots with indium and tin is explored. High-resolution nanoprobing confirms the presence of indium and tin in the particles and the inclusion of indium into the particles without forming a separate phase. The tin doped CdSe samples show preferential adsorption of tin in quantum dots from the solution during synthesis while incorporation of indium is somewhat statistical. In agreement with the expected n-type behavior, the photoluminescence (PL) of both indium and tin doped samples exhibits a significantly steeper temperature dependence, compared to undoped CdSe quantum dots. Comparison of theory and experimental data suggests that the approximate locations of the dopants levels are at 280 and 100 meV below the conduction band edge of the indium and tin doped quantum dots, respectively. The relative temperature dependent Stokes shifts of the doped samples are larger than those of the undoped sample, suggesting that the electron is backfilling the lowest unoccupied quantum dots levels. The oxidized doped samples exhibit increased polarized band-edge emission. The likely explanation of the polarized emission is that trapping times are fast in the oxidized doped samples compared to the undoped samples.

Developing electronic doping of colloidal quantum dots is important for basic science and technology. In this article, the doping of colloidal CdSe quantum dots with gallium atoms is reported. Gallium doping of CdSe quantum dots produces important changes in electronic and optical properties of the material. The gallium doping shows a significant impact on the growth kinetics of quantum dots, which reveals important clues about the mechanism of the gallium dopant incorporation into the CdSe. The results show that the gallium doping significantly impacts the conductivity of CdSe thin film made of the quantum dots as well as the photoluminescence and chemical reactivity of the quantum dots, in agreement with the expected ntype character.

CdSe nanorods and dilute poly(3-hexylthiophene) (P3HT) dispersed in poly(methyl methacrylate) (PMMA) films are investigated by wide field fluorescence microscopy and by analysis of single-point time transients. The data depict enhanced band-edge luminescence from nanorod/P3HT films, consistent with filling of CdSe surface traps by static charge transfer from P3HT. Band-edge luminescence from the nanorods is also shown to be enhanced by photoactivated (e.g., dynamic) charge transfer from P3HT to surface trap states on the CdSe nanorods. The role played by charge transfer in enhanced CdSe luminescence is further demonstrated by differences observed in the CdSe nanorod blinking behavior in P3HT and PMMA films.

Selenolato-bridged manganese­(I)-based dinuclear metallacycles [{(CO)3Mn­(μ-SeC6H5)2Mn­(CO)3}­(μ-L)] (1–4) were achieved in a single-step process by the self-assembly of dimanganese decacarbonyl, diphenyl diselenide, and flexible ditopic ester-functionalized pyridyl ligands [1, L = o-phenylene diisonicotinate (pdi); 2, L = 1,6-hexanediyl di-4-pyridine carboxylate (hdp); 3, L = 4-pyridine carboxylic acid diethylene glycol diester (pcadgd); 4, L = 4-pyridine carboxylic acid triethylene glycol diester (pcatgd)]. Synthesis of a series of selenolato-bridged dinuclear Mn­(I)-based metallacycles was facilitated via oxidative addition of C6H5Se–SeC6H5 to (CO)5Mn–Mn­(CO)5 with simultaneous coordination of flexible ditopic pyridyl linkers in an orthogonal fashion. The metallacycles were characterized by IR, UV–vis, NMR, and electrospray ionization-mass spectroscopic techniques and elemental analysis. Solid-state structural elucidation of 3 was carried out using single-crystal X-ray diffraction methods. In addition, anticancer activity studies were carried out for compounds 2–4 with various cancer cell lines. Furthermore, compound 3 was probed to evaluate its potential CO-releasing property using myoglobin assay.

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