정덕영 교수

Abstract Large‐scale (as much as 200 g in a batch) and surfactant‐free syntheses of the CuIn x Ga 1– x Se 2 and the CuIn x Ga 1– x S 2 nanoparticles were investigated by employing a sonochemical process under ambient conditions. This synthetic approach eliminates the need for organic stabilizers, which may act as an insulator in the final device, and reduces the number of reaction steps for synthesis of high‐quality CISe nanocrystals. We also demonstrate the solution‐based fabrication of the thi

We synthesized binder-free Co(OH)2 nanocrystals on nickel electrodes by the ammonia transfer method in an aqueous solution and kinetically-controlled their thickness and height to enhance the capacitance through the facile diffusion of electrolytes in the nanocrystals. As thinner Co(OH)2 films were developed, the specific capacitance increased up to 1260 F g(-1) at a current density of 10 A g(-1). A thin layer of graphene oxide (GO) was used to wrap the Co(OH)2 nanocrystals to create a pseudocap

Abstract Silicon oxide‐coated lithium aluminum layered double hydroxide (Li x Al 2 ‐LDH@SiO 2 ) nanocrystals (NCs) are investigated to selectively separate lithium cations in aqueous lithium resources. We directly synthesized Li x Al 2 ‐LDH NC arrays by oxidation of aluminum foil substrate under a urea and lithium solution. Various lithium salts, including Cl − , CO 3 2− , NO 3 − , and SO 4 2− , were applied in aqueous solution to confirm the anion effect on the captured and released lithium qua

A nanoink solution-based process was developed as a low-costing method for the fabrication of Cu(In,Ga)Se2 (CIGSe) thin-film photovoltaic cells. The sonochemical synthesis of CIGSe nanocrystals of the nanoink through step-by-step mixing of the reactants was investigated. To achieve the ideal stoichiometry of Cu(In0.7 Ga0.3 )Se2 to tune the bandgap and to fabricate high-efficiency photovoltaic cells, the synthetic parameters, the concentration of hydrazine, and the amount used of the gallium prec

Abstract The direct synthesis of nanostructured electrode materials on three‐dimensional substrates is important for their practical application in electrochemical cells without requiring the use of organic additives or binders. In this study, we present a simple two‐step process to synthesize a stable core–shell structured cobalt sulfide/cobalt aluminum hydroxide nanosheet (LDH‐S) for pseudocapacitor electrode application. The cobalt aluminum layered double hydroxide (CoAl‐LDH) nanoplates were

Abstract Monolayer assemblies of zeolite microcrystals, polymer nanobeads and caged proteins were successfully applied to a highly ordered MgAl‐LDH monolayer by using the electrostatic attractions between the negatively charged particles and positively charged MgAl‐LDH without chemical modifications. Ultrasonication leads to the monolayer assembly of ZSM‐5 microcrystals with a maximum preferred contact over the MgAl‐LDH monolayer, where the ZSM‐5 microcrystals are oriented in the (0 k 0) crystal

Mixture effects were studied on horizontal convective heat transfer for both nonazeotropic, R22/R114, and azeotropic, R12/R152a, mixtures. A test facility was designed, constructed, and operated to simulate evaporators in heat pump and refrigeration systems. More than 3000 local two-phase heat transfer coefficients were obtained under steady state condition for annular flow at a reduced pressure of 0.08. The results indicated that there were two distant heat transfer regions; partial boiling and