Tae‐Hyuk Kwon

Various iridium complexes consisting of phenylpyrazole (ppz) ligands and isoquinolinecarboxylic acids (iq) as ancillary ligands were designed by energy band-gap calculations via ab initio calculations and synthesized to give rise to various emission wavelengths as expected. Fine color tuning was achieved through varying the position of the methyl substituent on the phenylpyrazole moiety with HOMO electron densities. Additional color tuning was made possible by altering the LUMO through the use o

A series of efficient light-harvesting systems (FIr3mGx, x = 1−3) based on dendrimer donor (mCP: N,N‘-dicarbazolyl-3,5-benzene) derivatives coupled with a sky blue phosphorescent acceptor (FIrpic: iridium(III) bis[(4,6-difluorophenyl)pyridinato-N,C2‘]-3-hydroxypicolinate derivative) were prepared, and their photophysical properties were investigated. The light-harvesting ability of FIr3mGx (x = 1−3) increases with the number of energy donor mCP units. The acceptor PL intensity of the donor−accep

Dye-sensitized photo-rechargeable battery (DSPB) harvests and stores dim light efficiently, realizing indoor-light-harvesting battery to operate IoT devices successfully without sun light.

A one-pot synthesis of 2,6-dibromodithieno[3,2-b;2',3'-d]thiophene (dibromo-DTT, 4) was developed. A key step was bromodecarboxylation of DTT-2,6-dicarboxylic acid, obtained by saponification of the diester 1. The donor-acceptor dye DAHTDTT (13), based on a central 2,6-bis[2'-(3'-hexylthienyl)]dithieno[3,2-b;2',3'-d]thiophene core (9), was prepared and incorporated in a dye-sensitized solar cell (DSC), which exhibited an energy conversion efficiency of 7.3% with V(oc) of 697 mV, J(sc) of 14.4 mA

Abstract Here, a new method is presented to increase the turn‐on time and stability of light‐emitting electrochemical cells (LECs). To this end, a neutral iridium complex ( 5 ) containing a pendant Na + ion that is generally known to have a faster mobility in the solid film than bulky anions is introduced, instead of the classic ionic transition metal complex (iTMC) with counter anion ( 7 ). Synthesis, photophysical and electrochemical studies of these complexes are reported. In the device confi

Abstract A vacancy‐ordered double perovskite, Cs 2 SnI 6 , has emerged as a promising lead‐free perovskite in the optoelectronic field. However, the charge transfer kinetics mediated by its surface state remains unclear. Here, the charge transfer mechanism of Cs 2 SnI 6 is reported and the role of its surface state in the presence of a redox mediator is clarified. Specifically, charge transfer through the surface state of Cs 2 SnI 6 and its subsequent surface state charging are demonstrated by c

An ensemble sensor system that exhibited selective luminescence enhancement upon binding to thymidine 5'-triphosphate (TTP) in HEPES buffer over other nucleotides was developed. The ensemble system consisted of an energy acceptor (FIrpic-bis(Zn2+-dipicolylamine conjugate, FIrpic=bis[(4,6-difluorophenyl)-pyridinato-N,C2+]picolinate) derivative) and an energy donor (mCP-Zn2+-cyclen, mCP=N,N'-dicarbazolyl-3,5-benzene). Among the nucleotides, the selective recognition and luminescence enhancement fo

Aggregates of amyloidogenic peptides are involved in the pathogenesis of several degenerative disorders. Herein, an iridium(III) complex, Ir-1, is reported as a chemical tool for oxidizing amyloidogenic peptides upon photoactivation and subsequently modulating their aggregation pathways. Ir-1 was rationally designed based on multiple characteristics, including 1) photoproperties leading to excitation by low-energy radiation; 2) generation of reactive oxygen species responsible for peptide oxidat

The direct formation of CN and CO bonds from inert gases is essential for chemical/biological processes and energy storage systems. However, its application to carbon nanomaterials for improved energy storage remains technologically challenging. A simple and very fast method to form CN and CO bonds in reduced graphene oxide (RGO) and carbon nanotubes (CNTs) by an ultrasonic chemical reaction is described. Electrodes of nitrogen- or oxygen-doped RGO (N-RGO or O-RGO, respectively) are fabricat

A neutral tripod system for biotin-avidin assays, which is composed of biotin, FIrpic as an energy acceptor, and mCP as an energy donor, offers remarkable sensitivity over traditional transition metal based protein probes due to the intramolecular energy transfer and increased hydrophobicity associated with the avidin binding site and neutral probe 1.

Amyloidogenic peptides are considered central pathological contributors towards neurodegeneration as observed in neurodegenerative disorders [<i>e.g.</i>, amyloid-β (Aβ) peptides in Alzheimer's disease (AD)]; however, their roles in the pathologies of such diseases have not been fully elucidated since they are challenging targets to be studied due to their heterogeneous nature and intrinsically disordered structure. Chemical approaches to modify amyloidogenic peptides would be valuable in advanc

Conjugated microporous polymers (CMPs) are promising energy storage materials owing to their rigid and cross-linked microporous structures. However, the fabrication of nano- and microstructured CMP films for practical applications is currently limited by processing challenges. Herein, we report that combined sono-cavitation and nebulization synthesis (SNS) is an effective method for the synthesis of CMP films from a monomer precursor solution. Using the SNS, the scalable fabrication of microporo

Efficient and selective production of CH₄ through the CO₂ reduction reaction (CO2RR) is a challenging task due to the high amount of energy consumption and various reaction pathways. Here, we report the synthesis of Zn-based polyoxometalate (ZnPOM) and its application in the photocatalytic CO2RR. Unlike conventional Zn-based catalysts that produce CO, ZnPOM can selectively catalyze the production of CH₄ in the presence of an Ir-based photosensitizer (TIr3) throug

We report a 10% enhancement of the photovoltaic performance of polymer bulk heterojunction solar cells composed of an iridium complex, P3HT, PEO and PCBM.