Jong-Tae Lee

Single-layer graphene (SLG) was incorporated into ZnO nanoparticles (NPs), and use of this material in photovoltaic devices generated significant changes. The Fermi level of ZnO NPs underwent a downshift, whereas the conduction and valence bands were maintained with increasing SLG concentrations. Furthermore, the effective defect densities were reduced and carrier mobility was enhanced. Colloidal quantum dot photovoltaics (CQDPVs) with the SLG-incorporated ZnO NP layer as an electron transportin

Adsorption behaviors of dodecanethiol (C 12 H 25 SH) molecules are investigated on the surface of single‐walled carbon nanotubes (SWCNTs) with vibrational and X‐ray photoelectron spectrometers. The active adsorption sites are proved as Stone‐Wales (SW) defects (5–7 ring defects). The SW defect‐removed SWCNTs formed by reacting nanotubes with allyl acrylate molecules are compared with pristine SWCNTs in dispersion and field emission. The former shows higher dispersion and field emission than the

The present study examined whether cultural differences in the better‐than‐average effect (the tendency to view oneself as better than average) would vary with trait desirability and used Koreans and Americans as representatives of East Asian and Western cultures, respectively. In Study 1, the author found that the magnitude of cultural difference in the better‐than‐average effect varied between Americans and Koreans. Specifically, Korean participants failed to exhibit the better‐than‐average ef

Improving charge collection is one of the key issues for high-performance PbS colloidal quantum dot photovoltaics (CQDPVs) due to the considerable charge loss resulting from the low mobility and large defect densities of the 1,2-ethanedithiol-treated PbS quantum dot hole-transporting layer (HTL). To overcome these limitations, single-walled carbon nanotubes (SWNTs) and C₆₀-encapsulated SWNTs (C₆₀@SWNTs) are incorporated into the HTL in CQDPVs. SWNT-incorporated CQDPV demons

We fabricated quantum dot-sensitized solar cells (QDSSCs) using cadmium sulfide (CdS) and cadmium telluride (CdTe) quantum dots (QDs) as sensitizers. A spin coated <TEX>$TiO_2$</TEX> nanoparticle (NP) film on tin-doped indium oxide glass and sputtered Au on fluorine-doped tin oxide glass were used as photo-anode and counter electrode, respectively. CdS QDs were deposited onto the mesoporous <TEX>$TiO_2$</TEX> layer by a successive ionic layer adsorption and reaction method. Pre-synthesized CdTe

N-type ZnO nanorods were grown on p-type porous silicon using a chemical bath deposition (CBD) method (p-n diode). The structure and geometry of the device were examined by field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) while the optoelectronic properties were investigated by UV/Vis absorption spectrometry as well as photoluminescence and electroluminescence measurements. The field emission (FE) properties of the device were also measured and its turn-on field a

Upper-directionally grown nanorods were synthesized on a large scale by a simple method of direct heating of Cu foil in air. Hybrid CuO/ZnO nanorods were fabricated by ZnO thin film coating using magnetron sputtering. Field emission (FE) measurements of CuO and hybrid CuO/ZnO nanorod films show that they have turn-on field of 3.81 and 3.24 V/microm and a current density of 0.39 and 1.1 microA/cm2 under an applied field of about 6.6 V/microm, respectively. By comparing X-ray photoelectron spectro

A film of shaped CdS nanoparticle deposited single walled carbon nanotubes (CdS-SCWNTs) on silicon wafer is successfully fabricated by the method of layer-by-layer deposition cycle. The field emission (FE) properties of CdS-SWCNTs film are investigated for the first time. The film of CdS-SWCNTs exhibits better FE properties, a lower turn-on field, and a higher field enhancement factor than that of the film of pristine SWCNTs, for which the physical and chemical properties of the CdS nanoparticle

Single-walled carbon nanotubes (SWNTs) are known to have a p-type charge transfer character in the atmosphere. The energy state of SWNTs can be modulated by doping with either an electron donor or an acceptor. In this study, iodine molecules are chosen for intercalation to SWNTs to predict the charge transfer tendency between them. Field-effect transistors (FETs) using iodine intercalated SWNTs (I-SWNTs) are fabricated and their electronic properties are investigated to better understand the cha