Ho‐Jin Son

Given that energy (exciton) migration in natural photosynthesis primarily occurs in highly ordered porphyrin-like pigments (chlorophylls), equally highly ordered porphyrin-based metal-organic frameworks (MOFs) might be expected to exhibit similar behavior, thereby facilitating antenna-like light-harvesting and positioning such materials for use in solar energy conversion schemes. Herein, we report the first example of directional, long-distance energy migration within a MOF. Two MOFs, namely F-M

ConspectusDuring the last few decades, the design of catalytic systems for CO₂ reduction has been extensively researched and generally involves (1) traditional approaches using molecular organic/organometallic materials and heterogeneous inorganic semiconductors and (2) combinatory approaches wherein these materials are combined as needed. Recently, we have devised a number of new TiO₂-mediated multicomponent hybrid systems that synergistically integrate the intrinsic merit

A major loss mechanism in dye-sensitized solar cells (DSCs) is recombination at the TiO(2)/electrolyte interface. Here we report a method to reduce greatly this loss mechanism. We deposit insulating and transparent silica (SiO(2)) onto the open areas of a nanoparticulate TiO(2) surface while avoiding any deposition of SiO(2) over or under the organic dye molecules. The SiO(2) coating covers the highly convoluted surface of the TiO(2) conformally and with a uniform thickness throughout the thousa

Detachment (desorption) of molecular dyes from photoelectrodes is one of the major limitations for the long-term operation of dye-sensitized solar cells. Here we demonstrate a method to greatly inhibit this loss by growing a transparent metal oxide (TiO2) on the dye-coated photoelectrode via atomic layer deposition (ALD). TiO2-enshrouded sensitizers largely resist detachment, even in pH 10.7 ethanol, a standard solution for intentional removal of molecular dyes from photoelectrodes. Additionally

Color-tunable Zn(II) complexes of the type Zn( N,O-OPh (OxZ)ArX) 2 ( 5), where the ligand consists of an oxazolylphenolate ion connected at the 4-position by a 2,4-substituted aryl functional group with X = NMe 2 a, OMe b, Ph c, Cl d, F 2 e, and CN f, were prepared. X-ray structural studies of 5a, 5b, and 5e showed that a zinc atom was positioned in a distorted tetrahedral coordination environment created by two oxazolylphenolate ligands with N,O-chelation. Hammet plots of absorption and emissio

Dye aggregation and concomitant reduction of dye excited-state lifetimes and electron-injection yields constitute a significant mechanism for diminution of light-to-electrical energy conversion efficiencies in many dye-sensitized solar cells (DSCs). For TiO2-based DSCs prepared with an archetypal donor-acceptor organic dye, (E)-2-cyano-3-(5'-(5''-(p-(diphenylamino)phenyl)-thiophen-2''-yl)thiophen-2'-yl)acrylic acid (OrgD), we find, in part via ultrafast spectroscopy measurements, that postdye-ad

The photophysical and electrochemical properties of the two isomeric N-heterocyclic carbene Ir(<sc>iii</sc>) complexes were investigated.

The intramolecular photoinduced electron transfer (PET) processes of three bis(4-arylphenylamino benzo)-ortho-carboranes (ArCbAr, Ar = phenyl (Ph), naphthyl (Np) and pyrenyl (Py)) triads were investigated in CH₂Cl₂ and n-hexane using the femtosecond time-resolved transient absorption (TA) spectroscopic technique. In CH₂Cl₂, the transient S₁-S_n absorption band of 1ArCbAr* was observed at short delay times. Concomitant with the deca

A series of 2,3,4,5-tetraphenylsiloles (3), with a four- to six-membered silacyclo alkyl substituent at the 1,1'-position, have been prepared by a one-pot synthesis of dilithium diyne (2) with the corresponding silacycloalkyl dichlorosilane precursors (1). The structures of the resulting 1,1'-(silacyclopentenyl)silole (3b) and 1,1'-(silacyclopentyl)silole (3c) species were studied using X-ray crystallography to obtain geometrical information on exocyclic siloles. Due to the formation of silacycl

The divergent synthesis of end-capped silole dendrimers Gn-2n+1Silole (n = 1−4) using 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane [Me(CH2CH)SiO]4 as a core molecule and allyl alcohol/dichloromethylsilane as a building block is described in this paper. The reaction of the dichloride functionalities of the carbosiloxane dendrimers Gn-2n+2Cl (n = 1−4) with the 1,4-diphenylbutadiene-1,4-dianions (1) provided an effective route for the attachment of silole functionalities to a dendritic

In this study, an InP-cored quantum dot (InP-QD) material was prepared and physically immobilized on TiO2 particles functionalized with an archetypical reduction catalyst, (4,4-Y2-bpy)ReI(CO)3Cl (ReP, Y = CH2PO(OH)2), to form a new type of InP quantum dot-sensitized hybrid photocatalyst (InP-QD/TiO2/ReP) and evaluated as a lower-energy photosensitizer in this hybrid system. It was found that the TiO2 heterogenization of the InP-QD material promotes the photoexcited electron transfer process from

A series of trimethylsilyl-substituted dithieno-spiro-siloles (3), with a four- to six-membered silacycloalkyl substituent at the 1,1-position, were prepared by reacting 3,3′-dilithio-5,5′-bis(trimethylsilyl)-2,2′-dithiophene (2) with the corresponding silacycloalkyl dichlorosilane precursors (1). Arylamino-substituted bis(diarylamino)dithieno-spiro-siloles (6) were also prepared using the same synthetic protocol by reacting 3,3′-dilithio-5,5′-bis(diarylamino)-2,2′-dithiophene (5) with 1. A stru

We report the results of photoinduced electron transfer (PET) in a novel dyad, in which a boron dipyrromethene (BODIPY) dye is covalently linked to o-carborane ( o-Cb). In this dyad, BODIPY and o-Cb act as electron donor and acceptor, respectively. PET dynamics were investigated using a femtosecond time-resolved transient absorption spectroscopic method. The free energy dependence of PET in the S₁ and S₂ states was examined on the basis of Marcus theory. PET in the S<sub>1<

Efficient hybrid photocatalysts for carbon dioxide reduction were developed from dye-sensitized TiO₂ nanoparticles and their catalytic performance was optimized by ternary organic/inorganic components. Thus, the hybrid system consists of (E)-2-cyano-3-(5'-(5''-(p-(diphenylamino)phenyl)thiophen-2''-yl)thiophen-2'-yl)-acrylic acid as a sensitizer and fac-[Re(4,4'-bis(diethoxyphosphorylmethyl)-2,2'-bipyridine)(CO)₃Cl] as a reduction catalyst (ReP), both of which have been fixe