Hyo Jae Yoon

Abstract Self‐assembled monolayers (SAMs), owing to their unique and versatile abilities to manipulate chemical and physical interfacial properties, have emerged as powerful nanomaterials for improving the performance of perovskite solar cells (PSCs). Indeed, in the last six years, a collection of studies has shown that the application of SAMs to PSCs boosts the performance of devices compared to the pristine PSCs. This review describes recent studies that demonstrate the direct advantages of SA

Allosteric regulation of organometallic catalysts could allow for greater control over reactions. We report an allosteric supramolecular structure in which a monometallic catalytic site has been buried in the middle layer of a triple-layer complex. Small molecules and elemental anions can open and close this complex and reversibly expose and conceal the catalytic center. The ring-opening polymerization of ε-caprolactone can be turned on by the in situ opening of the triple-layer complex and then

Liquid metals are emerging as fluidic inorganic materials in various research fields. Micro- and nanoparticles of Ga and its alloys have received particular attention in the last decade due to their non toxicity and accessibility in ambient conditions as well as their interesting chemical, physical, mechanical, and electrical properties. Unique features such as a fluidic nature and self-passivating oxide skin make Ga-based liquid metal particles (LMPs) distinguishable from conventional inorganic

A supramolecular allosteric catalyst that exhibits a PCR-like cascade reaction is reported. The complex is triggered by a reaction with an acetate ion, which turns on a catalytic cascade that exponentially increases acetate ion concentration through an acyl transfer reaction.

Molecular rectification is a particularly attractive phenomenon to examine in studying structure-property relationships in charge transport across molecular junctions, since the tunneling currents across the same molecular junction are measured, with only a change in the sign of the bias, with the same electrodes, molecule(s), and contacts. This type of experiment minimizes the complexities arising from measurements of current densities at one polarity using replicate junctions. This paper descr

Insensitivity: A series of molecules containing a common head group and body as well as structurally varied tail groups (-R) has been used in junctions with the structure Ag/S(CH2)4CONH(CH2)2R//Ga2O3/EGaIn to study the rates of charge transport by tunneling. Changing the structure of R over a range of common aliphatic, aromatic, and heteroaromatic organic groups was found to not significantly influence the rate of tunneling (see plots; the dashed lines represent calibration standards).

A challenge in organic thermoelectrics is to relate thermoelectric performance of devices to the chemical and electronic structures of organic components inside them on a molecular scale. To this end, a reliable and reproducible platform relevant to molecular-level thermoelectric measurements is essentially needed. This paper shows a new, efficient approach for thermoelectric characterization of a large area of molecular monolayers using liquid eutectic gallium-indium (EGaIn). A cone-shaped EGaI

This paper describes a physical-organic study of the effect of uncharged, polar, functional groups on the rate of charge transport by tunneling across self-assembled monolayer (SAM)-based large-area junctions of the form AgTSS(CH2)nM(CH2)mT//Ga2O3/EGaIn. Here AgTS is a template-stripped silver substrate, -M- and -T are “middle” and “terminal” functional groups, and EGaIn is eutectic gallium–indium alloy. Twelve uncharged polar groups (-T = CN, CO2CH3, CF3, OCH3, N(CH3)2, CON(CH3)2, SCH3, SO2CH3,

Single-atom catalysts (SACs) hold the promise of utilizing 100% of the participating atoms in a reaction as active catalytic sites, achieving a remarkable boost in catalytic efficiency. Thus, they present great potential for noble metal-based electrochemical application systems, such as water electrolyzers and fuel cells. However, their practical applications are severely hindered by intrinsic complications, namely atom agglomeration and relocation, originating from the uncontrollably high surfa

Abstract Thermoelectric materials convert waste heat into electricity, making sustainable power generation possible when a temperature gradient is applied. Solar radiation is one potential abundant and eco‐friendly heat source for this application, where one side of the thermoelectric device is heated by incident sunlight, while the other side is kept at a cooler temperature. This is known as solar thermoelectric generation. Various thermoelectric materials are used for different solar thermoele

This review provides a comprehensive overview of advances in the last two decades in the physical-organic studies of molecular thermoelectrics.

Molecular electronics has received significant attention in the last decades. To hone performance of devices, eliminating structural defects in molecular components inside devices is usually needed. We herein demonstrate this problem can be turned into a strength for modulating the performance of devices. We show the systematic dilution of a monolayer of an organic rectifier (2,2'-bipyridine-terminated n-undecanethiolate) with electronically inactive diluents (n-alkanethiolates of different leng

The design and synthesis of a novel supramolecular allosteric catalyst, assembled via the weak-link approach, is presented. The catalyst shows completely reversible allosteric regulation for the catalytic cleavage of 2-(hydroxypropyl)-p-nitrophenyl phosphate (HPNP), which is an RNA model substrate. The system works under pseudo-aqueous conditions and can be turned completely off due to a bridging acetate ligand in the deactivated state, which inhibits the analogous intermolecular catalytic proce

Abstract Molecular electronics promise electronic devices that are miniaturized to molecular and atomic levels. Despite significant efforts made towards understanding and improving the electronic functions of devices based on homogeneous molecular systems, the roles, effects, and importance of molecular‐level dilution and mixing in active components for device performance have only recently begun to be understood. Recent advances in molecular electronics based on heterogeneous active components,