• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.457-465
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• 2014

Size-controlled lead sulfide (PbS) quantum dots were synthesized by the typical hot injection method using oleic acid (OA) as the stabilizing agent. Subsequently, the ligand exchange reaction between OA and thioacetic acid (TAA) was employed to obtain TAA-capped PbS quantum dots (PbS-TAA QDs). The condensation reaction of the TAA ligands on the surfaces of the QDs enhanced the conductivity of the PbS-TAA QDs thin films by about 2-4 orders of magnitude, as compared with that of the PbS-OA QDs thin films. The electron transport mechanism of the PbS-TAA QDs thin films was investigated by current-voltage (I-V) measurements at different temperatures in the range of 293 K-473 K. We found that the charge transport was due to sequential tunneling of charge carriers via the QDs, resulting in the thermally activated hopping process of Arrhenius behavior.

• 대한화학회지
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• 제17권5호
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• pp.385-386
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• 1973

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.242.1-242.1
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• 2003

The nucleoside analogue, L-FMUS was synthesized from L-FMAU which has been shown to have significant antiviral activity against hepatitis B virus (HBV). It was prepared by two steps. First, 5'hydroxyl of L-FMAU was substituted by thioacetyl group using diisopropylazodicarboxylate(DIAD), Triphenyl phosphine(PPh3) and thioacetic acid in anhydrous THF. (omitted)

• Applied Science and Convergence Technology
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• 제23권6호
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• pp.376-386
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• 2014

Zinc oxysulfide nanocrystals (ZnOS NCs) were synthesized by forming ZnS phase on a ZnO matrix. ZnO nanocrystals (NCs) with a diameter of 10 nm were synthesized by forced hydrolysis in an organic solvent. As-synthesized ZnO NCs aggregated with each other due to the high surface energy. As acetic acid (AA) was added into the milky suspension of the aggregated ZnO NCs, transparent solution of well dispersed ZnO NCs formed. Finally ZnOS NCs were formed by adding thioacetic acid (TAA) to the transparent solution. The effect of recrystallization on the structural, optical and electrical properties of the ZnOS NCs were studied. The results of UV-vis absorption confirmed the band gap tunability caused by increasing the curing temperature of ZnOS thin films. This may have originated from the larger effective size due to the recrystallization of zinc sulfide (ZnS). From XRD result we identified that ZnOS thin films have a zinc blende crystal structure of ZnS without wurtzite ZnO structure. This is probably due to the small amount of ZnO phases. These assertions were verified through EDS of FE-SEM, XPS and EDS mapping of HR-TEM results; we clearly proved that ZnOS were comprised of ZnS and ZnO phases.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.541-541
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• 2012

InP quantum dots capped by myristic acid (InP-MA QDs) were synthesized by a typical hot injection method using MA as stablizing agent. The current density across the InP-MA QDs thin film which was fabricated by spin-coating method is about $10^{-4}A/cm^2$ at the electric field of 0.1 MV/cm from I-V measurement on a metal-insulator-metal (MIM) device. The low conductivity of the InP-MA QDs thin film is interpreted as due to the long interdistances among the dots governed by the MA molecules. Therefore, replacing the MA with thioacetic acid (TAA) by biphasic ligand exchange was conducted in order to obtain TAA capped InP QDs (InP-TAA). InP-TAA QDs were designed due to: 1) the TAA is very short molecule; 2) the thiolate groups on the surface of the InP-TAA QDs are expected to undergo condensation reaction upon thermal annealing which connects the QDs within the QD thin film through a very short linker -S-; and 3) TAA provides better passivation to the QDs both in the solution and thin film states which minimizing the effect of surface trapping states.