Ilseung Yang

Highly Luminescent InP/GaP/ZnS Nanocrystals and Their Application to White Light-Emitting Diodes

Highly stable and luminescent InP/GaP/ZnS QDs with a maximum quantum yield of 85% were synthesized by in situ method. The GaP shell rendered passivation of the surface and removed the traps. TCSPC data showed an evidence for the GaP shell. InP/GaP/ZnS QDs show better stability than InP/ZnS. We studied the optical properties of white QD-LEDs corresponding to various QD concentrations. Among various concentrations, the white QD-LEDs with 0.5 mL of QDs exhibited a luminous efficiency of 54.71 lm/W, Ra of 80.56, and CCT of 7864 K.

Europium-doped gadolinium sulfide nanoparticles as a dual-mode imaging agent for T1-weighted MR and photoluminescence imaging.

We present a facile synthesis of europium-doped gadolinium sulfide (GdS:Eu(3+)) opto-magnetic nanoparticles (NPs) via sonochemistry. Their photoluminescence and strong paramagnetic properties enable these NPs to be utilized as an in vitro cell imaging and in vivo T(1)-weighted MR imaging probe. The GdS:Eu(3+) NPs have a prominent longitudinal (r(1)) relaxivity value, which is a critical parameter for T(1)-weighted MR imaging. Here, we showed not only their strong positive contrast effect to blood vessels and organs of mice, but also blood half-life and biodistribution including clearance from organs, in order to assess the GdS:Eu(3+) NPs as a competent nanocrystal-based T(1) contrast agent. We further showed confocal images of breast cancer cells containing GdS:Eu(3+) NPs to evaluate as a photoluminescence probe. Dual-mode imaging capability obtained from the GdS:Eu(3+) NPs will allow target-oriented cellular imaging as well as the resulting disease-specific MR imaging.

Photodissociation Dynamics of Acetone in the Gas Phase and in Solution Studied by Transient Absorption and Femtosecond Stimulated Raman Spectroscopy

Photodissociation dynamics of acetone was investigated for the first time in the gas phase and also in solution by transient absorption and femtosecond stimulated Raman spectrscopy. In the gas phase, a Rydberg state with a decay time of 350 fs, which in solution decays at ∼100 fs. In solution. we also found evidence for solvated electron generation. Vibrational information about the photodissociation dynamics was investigated in the gas phase by femtosecond stimulated Raman spectroscopy. Vibrational peaks for the nR state were observed at 1835 cm−1 C = O stretching and at 3100 cm−1 for C−H stretching.