Nak-Jung Kim

[reaction: see text] A new and novel Au-catalyzed cycloisomerization of ynals bearing a pendant unsaturated bond leading to synthetically valuable [6.7.n]-tricyclic compounds were developed. This study strongly supports the intermediacy of [3 + 2] cycloaddition proposed by DFT calculation and provides an easy access to key skeletons found in a variety of natural products.

We review herein the development of unipolar n-type polymer semiconductors in organic field-effect transistors, which would enable large-scale deployment of printed electronics in combination with a fast-growing area of p-type counterparts. After discussing general features of electron transport in organic semiconductors, various π-conjugated polymers that are capable of transporting electrons are selected and summarized to outline the design principles for enhancing electron mobility and stabil

A novel and highly efficient dye, Ru(H 2 dcbpy)(4-(4-( N, N -di( p -hexyloxyphenyl)amino)styryl)-4′-methyl-2,2′-bipyridine)(NCS) 2, HMP-2, with extinction coefficients of about 33 260 L·mol −1 ·cm −1 at 534 nm and about 20 000 L·mol −1 ·cm −1 at 490 nm, is designed and further applied onto ZnO nanocrystals for dye-sensitized solar cells application. ZnO nanocrystals of a few nanometers are spin coated onto an indium−tin oxide substrate for forming about 2.5 μm uniform film thickness. Change in t

ZnSe/ZnS:Mn core/(doped) shell and ZnSe/ZnS:Mn/ZnS core/(doped) shell/shell nanocrystals (NCs) that emit white light were synthesized in aqueous media. White light emission of as-prepared NCs is a result of combined emission of blue light (emission from band gap of ZnSe core) and yellow/orange light (4T1–6A1 emission from Mn2+ ions doped in ZnS of the first shell). Especially, the green emission generated from surface defects was found as a key factor that affects the photoluminescence quantum y

Abstract The photorefractivity of a non‐conjugated main‐chain polymeric composite, composed of electron‐rich N,N ‐di‐toly‐ N,N′ ‐diphenylbiphenyldiamine doped with 2‐{3‐[( E )‐2‐(piperidino)‐1‐ethenyl]‐5,5‐dimethyl‐2‐cyclohexenylidene}‐malononitrile (P‐IP‐DC) and [6,6]‐phenyl‐C 61 ‐butyric acid methyl ester (PCBM), is studied using two‐beam coupling and degenerate four‐wave mixing at 633 nm. The N,N′ ‐di‐toly‐ N,N′ ‐diphenylbiphenyldiamine‐based composite shows a gain coefficient of 215 cm −1 at

We investigated a dependence of the grating formation on the temperature in polymeric photorefractive (PR) composite, in terms of magnitude and buildup speed of the PR grating. For polymeric PR materials, the temperature is one of the most important factors together with the external electric field because it is closely related on photocharge generation efficiency, mobility of generated carrier, electro-optic coefficient tensor, and so on. Above the glass transition temperature, the diffraction

Abstract New heteroaromatic polymer containing quinoline unit in the main chain, poly[2,6‐( p ‐phenoxy)‐4‐phenyl quinoline] (PQ), was synthesized by the acid‐catalyzed self‐condensation reaction [Friedländer quinoline synthesis] of 4‐amino‐4′‐acetyl‐3‐benzoyldiphenyl ether, and its chemical structure was characterized by IR and NMR spectra and also by elemental analysis. The PQ was soluble in common organic solvents such as chloroform or tetrahydrofuran; thus a strong coherent film of this polym

New water-soluble and highly luminescent ZnSe/ZnS:Mn/ZnS core/shell/shell nanocrystals with color-tunable emission range between 580 and 600 nm were synthesized via a three-step in single flask method.

Abstract 7 H ‐Dibenzo[ a,g ]carbazole‐substituted polysiloxane (PSX‐[ a,g ]BCz) has been synthesized by hexachloroplatinate (IV) hydrate polymerization from poly(methylhydrosiloxane) and 7‐ally‐7 H ‐dibenzo[ a , g ]carbazole. PSX‐[ a,g ]BCz composite showed large orientational birefringences because of both large dipole moments and high‐polarizability anisotropies of P‐IP‐DC chromophore associated with the effective conjugation along the polyene. The 50‐μm thick photorefractive material containi