Heejae Kim

ADVERTISEMENT RETURN TO ISSUEPREVReviewNEXTInfrared Probes for Studying the Structure and Dynamics of BiomoleculesHeejae Kim† and Minhaeng Cho*†‡View Author Information† Department of Chemistry, Korea University, Seoul 136-713, Korea‡ Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136-713, Korea*E-mail: [email protected]. Tel.: +82-2-3290-3133. Fax: +82-2-3290-3121.Cite this: Chem. Rev. 2013, 113, 8, 5817–5847Publication Date (Web):May 16, 2013Publication History

Methylammonium lead iodide perovskite is an outstanding semiconductor for photovoltaics. One of its intriguing peculiarities is that the band gap of this perovskite increases with increasing lattice temperature. Despite the presence of various thermally accessible phonon modes in this soft material, the understanding of how precisely these phonons affect macroscopic material properties and lead to the peculiar temperature dependence of the band gap has remained elusive. Here, we report a strong

We report that UV–ozone treatment of TiO2 anatase thin films is an efficient method to increase the conductance through the film by more than 2 orders of magnitude. The increase in conductance is quantified via conductive scanning force microscopy on freshly annealed and UV–ozone-treated TiO2 anatase thin films on fluorine-doped tin oxide substrates. The increased conductance of TiO2 anatase thin films results in a 2% increase of the average power conversion efficiency (PCE) of methylammonium le

The critical aggregation phenomena are ubiquitous in many self-assembling systems. Ions in high salt solutions could also spontaneously form larger ion aggregates, but their effects on hydrogen-bond structures in water have long been controversial. Here, carrying out molecular dynamics (MD) simulation studies of high salt solutions and comparing the MD simulation results with infrared absorption and pump-probe spectroscopy of O-D stretch mode of HDO in highly concentrated salt solutions and (13)

Whereas there is increasing evidence for ion-induced protein destabilization through direct ion-protein interactions, the strength of the binding of anions to proteins relative to cation-protein binding has remained elusive. In this work, the rotational mobility of a model amide in aqueous solution was used as a reporter for the interactions of different anions with the amide group. Protein-stabilizing salts such as KCl and KNO3 do not affect the rotational mobility of the amide. Conversely, pro

Regular arrays of nonadherent B cells over large areas were produced with the use of micropatterned molecular templates consisting of a newly designed poly(allylamine)-g-poly(ethylene glycol) polycation graft copolymer. Polymer-on-polymer stamping (POPS) techniques were applied successfully to create micron scale patterns of the graft copolymer on negatively charged multilayer surfaces without losing resistance to the nonspecific adsorption of proteins. To generate templates for B cell arrays, t

Quantum dot color conversion layers have the potential to greatly improve the efficiency and color performance of displays including and beyond liquid crystal displays. To fully realize these improvements, the quantum dots must be deposited and patterned at high resolution. One promising method for achieving this is through inkjet printing. In this paper we report on the fabrication and characterization of quantum dot inks, as well as films made from inkjet deposition of these materials.

Specific ion effects on water dynamics and local solvation structure around a peptide are important in understanding the Hofmeister series of ions and their effects on protein stability in aqueous solution. Water dynamics is essentially governed by local hydrogen-bonding interactions with surrounding water molecules producing hydration electric field on each water molecule. Here, we show that the hydration electric field on the OD bond of HOD molecule in water can be directly estimated by measur

The interplay of electronic and nuclear degrees of freedom in semiconductor hybrid organic-inorganic perovskites determines many of their fundamental photophysical properties. For instance, charge carriers are dressed with phonons, that is, form polarons, and combination modes composed of strongly mixed localized vibrations and delocalized phonons can provide pathways for electronic energy relaxation and dissipation. Mixing of the different types of nuclear motion in vibrational combination mode

The thiocyanate (SCN(-)) anion is known as one of the best denaturants, which is also capable of breaking the hydrogen-bond network of water and destabilizing native structures of proteins. Despite prolonged efforts to understand the underlying mechanism of such Hofmeister effects, detailed dynamics of the ions in a highly concentrated solution have not been fully elucidated yet. Here, we used a dispersive IR pump-probe spectroscopic method to study the dependence of vibrational lifetimes and ro

Phosphoric acids have emerged as efficient organo-catalysts for various reactions. Despite widespread use, details of the reaction intermediates giving rise to stereocontrol have remained elusive. To clarify the nature of the catalyst–substrate interaction, we characterize and quantify catalyst–substrate complex formation by combining dielectric spectroscopy, quantum chemistry, and 1 H NMR spectroscopy. For a series of different solvents, the interaction between substrate and catalyst is dominat

Abstract A new concept for analysis of operational characteristic of ac‐PDP is proposed in this paper. The physical state of ac‐PDP cell is defined in terms of wall voltages, which can be traced through the various stages of PDP driving sequence. The voltage domain analysis in combination with firing voltage measurement identifies the cell state and allows the estimation of wall voltage difference between two different cell states. Firing voltage measurement also presented invaluable information

For many applications, increasing synergy between distinct proteins through organization is important for the specificity, regulation, and overall reaction efficiency. Although there are many examples of protein complexes in nature, a generalized method to create these complexes remains elusive. Many conventional techniques such as random chemical conjugation, physical adsorption onto surfaces, and encapsulation within matrices are imprecise approaches and can lead to deactivation of protein nat