20601-83-6Relevant academic research and scientific papers
2-(N,N-Dimethylamino)ethylselenolates of cadmium(II): Syntheses, structure of [Cd3(OAc)2(SeCH2CH2NMe2 )4] and their use as single source precursors for the preparation of CdSe nanoparticles
Kedarnath,Dey, Sandip,Jain, Vimal K.,Dey, Gautam K.,Varghese, Babu
, p. 2383 - 2391 (2006)
The reaction of Cd(OAc)2 · 2H2O with NaSeCH2CH2NMe2 gave a homoleptic cadmium selenolate, [Cd(SeCH2CH2NMe2)2]. The latter complex, on treatment with Cd(OAc)2 · 2H2O, afforded [Cd3(OAc)2(SeCH2CH2NMe2 )4], which was structurally characterized by single-crystal X-ray diffraction analysis. Pyrolysis of [Cd(SeCH2CH2NMe2)2] either in a mixture of hot hexadecylamine (HDA) and tri-n-octylphosphine oxide (TOPO) or in a furnace (180 and 200 °C) gave CdSe nanoparticles with average sizes varying between 3 and 21 nm. Both cubic and hexagonal phases of CdSe nanoparticles have been isolated under different experimental conditions. The CdSe nanoparticles were characterized by UV-Vis, photoluminescence, X-ray diffraction and electron microscopy. Time resolved luminescence measurements showed three different decay times for both band edge and trap state emissions.
Molecular clusters of binary and ternary mercury chalcogenides: Colloidal synthesis, characterization, and optical spectra
Kuno, Masaru,Higginson, Keith A.,Qadri, Syed B.,Yousuf, Mohammad,Lee, Sang Ho,Davis, Benjamin L.,Mattoussi, Hedi
, p. 5758 - 5767 (2003)
A series of binary (HgSe) and ternary (HgSe1-xSx) mercury chalcogenide clusters are synthesized utilizing a colloidal technique involving the phase separation of metal and chalcogen precursors in the presence of strong Hg(II) coordinating ligands. The clusters vary in size between 2 and 3 nm and possess the cubic zinc blende structure of the bulk. Energy-dispersive X-ray measurements show that the composition of the ternary material can be varied throughout the entire composition range from HgS to HgSe. In all cases, the linear absorption of these binary and ternary species is narrow with well-resolved transitions at both the band edge and at higher energies. Complementary band edge emission is also observed with no apparent deep trap emission. Size- and composition (x)-dependent optical properties of these clusters are investigated using photoluminescence (PL) and photoluminescence excitation (PLE) spectra. In the case of HgSe clusters, the size-dependent behavior of up to four excited states is followed. For HgSe1-xSx clusters, where x varies from 0 to 1, a size/composition-dependent progression of up to five excited states is observed.
Optimization studies of HgSe thin film deposition by electrochemical atomic layer epitaxy (EC-ALE)
Venkatasamy, Venkatram,Mathe, Mkhulu K.,Cox, Stephen M.,Happek, Uwe,Stickney, John L.
, p. 4347 - 4351 (2006)
Studies of the optimization of HgSe thin film deposition using electrochemical atomic layer epitaxy (EC-ALE) are reported. Cyclic voltammetry was used to obtain approximate deposition potentials for each element. These potentials were then coupled with their respective solutions to deposit atomic layers of the elements, in a cycle. The cycle, used with an automated flow deposition system, was then repeated to form thin films, the number of cycles performed determining the thickness of the deposit. In the formation of HgSe, the effect of Hg and Se deposition potentials, and a Se stripping potential, were adjusted to optimize the deposition program. Electron probe microanalysis (EPMA) of 100 cycle deposits, grown using the optimized program, showed a Se/Hg ratio of 1.08. Ellipsometric measurements of the deposit indicated a thickness of 19 nm, where 35 nm was expected. X-ray diffraction displayed a pattern consistent with the formation of a zinc blende structure, with a strong (1 1 1) preferred orientation. Glancing angle fourier transform infrared spectroscopy (FTIR) absorption measurements of the deposit suggested a negative gap of 0.60 eV.
Pyrimidyl-2-selenolates of cadmium and mercury: Synthesis, characterization, structures and their conversion to metal selenide nano-particles
Sharma, Rakesh K.,Wadawale, Amey,Kedarnath,Vishwanadh,Jain, Vimal K.
, p. 90 - 96 (2014)
Reactions of [MCl2(tmeda)] (M = Cd or Hg; tmeda = N,N,N′,N′-tetramethylethylenediamine) with NaSeC4H(R-4,6) 2N2 (R = H or Me) gave selenolate complexes of the general formula [M{SeC4H(R-4,6)2N2} 2(tmeda)n] (M/R/n = Cd/H/1 (1); Cd/Me/1 (2); Hg/H/1 (3) and Hg/Me/0 (4)). The chloro complexes of general formula, [MCl{SeC 4H(Me-4,6)2N2}(tmeda)] (M = Cd (6) or Hg (7)) have been synthesized by redistribution reaction of [M{SeC4H(Me-4,6) 2N2}2] with MCl2 followed by treatment with tmeda. The complexes have been characterized by elemental analysis, UV-Vis and NMR (1H, 13C, 77Se, 113Cd and 199Hg) spectroscopy. The molecular structures of [Cd{SeC4H(Me-4,6)2N2}2(tmeda)] and [Hg{SeC4H(Me-4,6)2N2}2] were established by single crystal X-ray diffraction. The complex, [Cd{SeC 4H(Me-4,6)2N2}2(tmeda)] comprises of an octahedral cadmium atom containing chelating, two SeC4H(4,6-Me) N2 and one tmeda, ligands. The complex, [Hg{SeC4H(Me-4,6) 2N2}2] has a linear structure with monodentate selenolate ligand. Thermolysis of [Cd{SeC4H(Me-4,6)2N 2}2(tmeda)] and [Hg{SeC4H(Me-4,6) 2N2}2] in various coordinating solvents afforded CdSe and HgSe nanoparticles which were characterized by UV-Vis, XRD, SEM, EDX and TEM.
Mercury Chalcohalide Semiconductor Hg3Se2Br2 for Hard Radiation Detection
Li, Hao,Meng, Fang,Malliakas, Christos D.,Liu, Zhifu,Chung, Duck Young,Wessels, Bruce,Kanatzidis, Mercouri G.
, p. 6446 - 6453 (2016)
Hg3Se2Br2 is a wide band gap semiconductor (2.22 eV) with high density (7.598 g/cm3) and crystallizes in the monoclinic space group C2/m with cell parameters of a = 17.496 (4) ?, b = 9.3991 (19) ?, c = 9.776(2) ?, β = 90.46(3)°, V = 1607.6(6) ?3. It melts congruently at a low temperature, 566 °C, which allows for an easy single crystal growth directly from the stoichiometric melt. Single crystals of Hg3Se2Br2 up to 1 cm long have been grown using the Bridgman method. Hg3Se2Br2 single crystals exhibit a strong photocurrent response when exposed to Ag X-ray and blue diode laser. The resistivity of Hg3Se2Br2 measured by the two probe method is on the order of 1011 cm, and the mobility-lifetime product (μτ) of the electron and hole carriers estimated from the energy spectroscopy under Ag X-ray radiation are (μτ)e ≈ 1.4 × 10-4 cm2/V and (μτ)h ≈ 9.2 × 10-5 cm2/V. Electronic structure calculations at the density functional theory level indicate a direct band gap and a relatively small effective mass for carriers. On the basis of the photoconductivity and hard X-ray spectrum, Hg3Se2Br2 is a promising candidate for X-ray and γ-ray radiation detection at room temperature.
Thallium mercury chalcobromides, TlHg6Q4Br 5 (Q = S, Se)
Wibowo, Arief C.,Malliakas, Christos D.,Chung, Duck Young,Im, Jino,Freeman, Arthur J.,Kanatzidis, Mercouri G.
, p. 11875 - 11880 (2013)
The new compounds TlHg6Q4Br5 (Q = S, Se) are reported along with their syntheses, crystal structures, and thermal and optical properties, as well as electronic band structure calculations. Both compounds crystallize in the tetragonal I4/m space group with a = 14.145(1) ?, c = 8.803(1) ?, and dcalc = 7.299 g/cm3 for TlHg6S4Br5 (compound 1) and a = 14.518(2) ?, c = 8.782(1) ?, and dcalc = 7.619 g/cm3 for TlHg6Se4Br5 (compound 2). They consist of cuboid Hg12Q8 building units interconnected by trigonal pyramids of BrHg3, forming a three-dimensional structure. The interstitial spaces are filled with thallium and bromide ions. Compounds 1 and 2 melt incongruently and show band gaps of 3.03 and 2.80 eV, respectively, which agree well with the calculated ones. First-principles electronic structure calculations at the density functional theory level reveal that both compounds have indirect band gaps, but there also exist direct transitions at energies similar to the indirect gaps.
Bis(l-methyIimidazolyl)diselenide and l-methylimidazole-2-selenolate complexes of zinc, cadmium, and mercury: Synthesis, characterization, and their conversion to metal selenide quantum dots
Kedarnath, Gotluru,Kumbhare, Liladhar Baburao,Jain, Vimal Kumar,Wadawale, Amey,Dey, Gautam Kumar,Thinaharan, Chidamabaranathan,Naveen, Shivalingegowda,Sridhar, Mandayam Anandalwar,Prasad, Javaregowda Shashidhara
, p. 489 - 494 (2008)
Treatment of a methanolic solution of metal acetate with bis(l-methylimidazolyl)diselenide, [(MelmSe)2], yields complexes of composition [M(OAc)2{(MeImSe)2}] (M = Zn, Cd, or Hg) whereas reactions of [MX2(M2NCH2CH 2-NMe2)] (X = CI or OAc) with sodium 1 -methylimidazole-2-selenolate gave selenolate complexes of the general formula [M(MeImSe)2] (M = Zn or Cd). The complexes were characterized by elemental analysis, IR, UV-vis, NMR (1H, 13C, and 77Se) data. The crystal structure of [Cd(OAc)2{(MeImSe)2}] was established by single-crystal X-ray diffraction. The cadmium atom adopts a distorted octahedral configuration defined by asymmetrically chelated acetate groups and chelating diselenide ligand. Thermal behavior of adducts was studied by thermogravimetric analysis. Pyrolysis in hexadecylamine/tri-n-octylphosphine oxide gave MSe quantum dots, which were characterized by UV-vis, photolumi-nescence, XRD, EDAX, SAED, and TEM.
Formation of HgSe thin films using electrochemical atomic layer epitaxy
Mathe, Mkhulu K.,Cox, Steve M.,Venkatasamy, Venkatram,Happek, Uwe,Stickney, John L.
, p. C751-C755 (2005)
The growth of HgSe using electrochemical atomic-layer epitaxy (EC-ALE) is reported. EC-ALE is the electrochemical analog of ALE, where electrochemical surface-limited reactions referred to as underpotential deposits, generally result in the formation of an atomic layer of an element, under controlled potential. HgSe thin films were formed on gold substrates using two reactant solutions: a solution of Hg2+ complexed with ethylenediaminetetraacetic acid and a HSeO3- ion solution. X-ray diffraction analysis showed a zinc blende structure for the deposits, with a strong (111) preferred texture, and an average grain size of 425Δ. Electron probe microscope analysis showed near-stoichiometric deposits. Fourier transform infrared spectroscopy reflection absorption measurements suggest two bandgaps: 0.42 and 0.88 eV.
SURFACE DERIVATIZATION AND ISOLATION OF SEMICONDUCTOR CLUSTER MOLECULES.
Steigerwald,Alivisatos,Gibson,Harris,Kortan,Muller,Thayer,Duncan,Douglass,Brus
, p. 3046 - 3050 (1988)
The authors describe a synthesis of nanometer-sized clusters of CdSe using organometallic reagents in inverse micellar solution and chemical modification of the surface of these cluster compounds. In particular we show how the clusters grow in the presence of added reagents and how the surface may be terminated and passivated by the addition of organoselenides. Passivation of the surface allows for the removal of the cluster molecules from the reaction medium and the isolation of organometallic molecules which are zinc blende CdSe clusters terminated by covalently attached organic ligands. Preliminary cluster characterization via resonance Raman, infrared, and NMR spectroscopy, X-ray diffraction, transmission electron microscopy, and size-exclusion chromatography is reported.
Incorporation of A2Q into HgQ and dimensional reduction to A2Hg3Q4 and A2Hg6Q7 (A = K, Rb, Cs; Q = S, Se). Access of Li ions in A2Hg6Q7 through topotactic ion-exchange
Axtell III, Enos A.,Park, Younbong,Chondroudis, Konstantinos,Kanatzidis, Mercouri G.
, p. 124 - 136 (1998)
The synthesis of the one-dimensional K2Hg3Q4 (Q = S, Se) and Cs2Hg3Se4 and the three-dimensional A2Hg6S7 (A = K, Rb, Cs), and A2Hg6Se7 (A = Rb, Cs) in reactive A2Q(x) fluxes is reported. Pale yellow, hexagonal plates of K2Hg3S4 crystallize in space group Pbcn, with a = 10.561(5) ?, b = 6.534(3) ?, and c = 13.706(2) ?, V = 945.8(7) ?,3 d(calc) = 5.68 g/cm3, and final R = 5.7%, R(w) = 6.3%. Red, hexagonal plates of K2Hg3Se4 crystallize in space group Pbcn, with a = 10.820(2) ?, b = 6.783(1) ?, and c 14.042(2) ?, v = 1030.6(5) ?,3 d(calc) = 6.42 g/cm3, and final R = 7.7%, R(w) = 8.4%. Orange yellow, hexagonal plates of Cs2Hg3Se4 crystallize in space group Pbcn, with a = 12.047(4) ?, b = 6.465(2) ?, and c = 14.771(6) ?, V = 1150.4(7) ?, 3 d(calc) = 6.83 g/cm3, and final R = 5.5%, R(w) = 6.2%. Black needles of K2Hg6S7 crystallize in space group P421m, with a = 13.805(8) ? and c = 4.080(3) ?, V = 778(1) ?, 3 d(calc) = 6.43 g/cm3, and final R = 3.1%, R(w) 3.6%. Black needles of Rb2Hg6S7 crystallize in space group P42nm, with a = 13.9221(8) ? and c = 4.1204(2) ?, V = 798.6(1) ?, 3 d(calc) = 6.65 g/cm3, and final R = 4.3%, R(w) = 5.0%. Black needles of Cs2Hg6S7 crystallize in space group P42nm, with a = 13.958(4) ? and c = 4.159(2) ?, V = 810.2(8) ?, 3 d(calc) = 6.94 g/cm3, and final R = 4.3%, R(w) = 4.4%. Black needles of Cs2Hg6Se7 crystallize in space group P42nm, with a = 14.505(7) ? and c = 4.308(2) ?, V = 906(1) ?, 3 d(calc) = 7.41 g/cm3, and final R = 3.6%, R(w) = 4.0%. The A2Hg3Q4 compounds Contain linear chains. The A2Hg6Q7 compounds display noncentrosymmetric frameworks with A+ cations residing in tunnels formed by both tetrahedral and linear Hg atoms. K2Hg6S7, Rb2Hg6S7, Cs2Hg6S7, Rb2Hg6Se7, and Cs2Hg6Se7 display room-temperature bandgaps of 1.51, 1.55, 1.61, 1.13, and 1.17 eV, respectively. Bandgap engineering through S/Se solid solutions of the type Rb2Hg6Se(7-x)S(x) and Cs2Hg6Se(7-x)S(x) is possible in-these materials. All A2Hg6Q7 melt congruently, with melting points of 556 ± 10 °C, except for Rb2Hg6Se7 which degrades. Rb2Hg6S7 can undergo ion exchange reactions with LiI to give Li1.8Rb0.2Hg6S7.
