Hwan Kyu Kim

Abstract A new series of 4‐hexyl‐4 H ‐thieno[3,2‐ b ]indole (HxTI) based organic chromophores is developed by structural engineering of the electron donor (D) group in the D–HxTI–benzothiadiazole‐phenyl‐acceptor platform with different fluorenyl moieties, such as unsubstituted fluorenyl (SGT‐146) and hexyloxy (SGT‐147), decyloxy (SGT‐148) and hexyloxy‐phenyl substituted (SGT‐149) fluorenyl moieties. In comparison to a reference dye SGT‐137 with a biphenyl‐based donor, the effects of the donating

A new class of silicon-containing poly(p-phenylenevinylene)-related copolymers with a uniform π-conjugated segment regulated by organosilicon units was synthesized by the well-known Wittig reaction between the appropriate diphosphonium salts and the dialdehyde monomer such as terephthaldicarboxaldehyde, 2,5-thiophenedicarboxaldehyde, and N-(2-ethylhexyl)-3,6-diformylcarbazole. The resulting polymers were highly soluble in common organic solvents. They could spin cast onto various substrates to g

A redox electrolyte is a crucial part of dye-sensitized solar cells (DSSCs), which plays a significant role in the photovoltage and photocurrent of the DSSCs through efficient dye regeneration and minimization of charge recombination. An I^-/I₃ ^- redox shuttle has been mostly utilized, but it limits the open-circuit voltage (<i>V</i> _oc) to 0.7-0.8 V. To improve the <i>V</i> _oc value, an alternative redox shuttle with more positive redox pote

The thermally stable second-order nonlinear optic (NLO) hybrid materials were successfully prepared by a sol−gel process using dye-attached sol−gel monomers (ormosils) of difunctionalized or trifunctionalized second-order NLO chromophores attached to silicon atoms. The dye-attached sol−gel monomers were synthesized by the coupling reaction of 3-isocyanatopropyltriethoxysilane with the corresponding functionalized NLO chromophores in DMAc. The dye-attached sol−gel monomers were homopolymerized an

Nb-doped anatase TiO2 nanoparticles were prepared by the sol–gel process followed by a hydrothermal treatment and successfully used as the photoanodes in organic dye-sensitized solar cells (DSSCs). Phase identification of the TiO2 samples was confirmed by X-ray diffraction and Raman shift spectroscopy. The electronic structure and Nb doping in the TiO2 lattice were confirmed by X-ray photoelectron spectroscopy and energy-disperse X-ray spectroscopy, respectively. Also, the conduction band edge (

A high solar-to-electricity conversion efficiency of 7.22% was achieved with a short circuit current (J(sc)) of 15.30 mA cm(-2), an open circuit voltage (V(oc)) of 669 mV and a fill factor (FF) of 0.71 for the 2Flu-ZnP-CN-COOH dye with a multi-functional co-adsorbent, under 100 mW cm(-2) AM 1.5 G simulated light.

Edge-carboxylated graphene nanoplatelets (ECGnPs) prepared by the dry ball-milling of graphite showed lower charge-transfer resistance (<italic>R</italic>_CT) and better electrochemical stability for the JK-303-based solar cell with Co(bpy)₃^2+/3+ redox couple.

A series of push–pull structured (D–π–A) porphyrin dyes with an electron-donating group (EDG) attached at the meso-position (HP, EHOP and HOP) were designed and synthesized for use as sensitizers in dye-sensitized solar cells (DSSCs). The nature of the EDG exerts a significant influence on the spectral, electrochemical and photovoltaic properties of these sensitizers. The absorption bands of these porphyrin dyes are broadened and red-shifted upon introduction of alkoxy chains to the electron-don

Three phenothiazine-based A-π-D-π-D-π-A-type small molecules containing various terminal acceptor units, which act as Lewis base blocks, have been synthesized via an efficient and step-economical, direct C-H arylation strategy in the aim toward the development of hole-transporting materials (HTMs) with multifunctional features (such as efficient hole extraction layer, trap passivation layer, and hydrophobic protective layer) for perovskite solar cells (PrSCs). Optical-electrochemical correlation

We have developed 4-(bis(9,9-dimethyl-9H-flouren-2-yl)amino)benzoic acid (HC-Acid) to use as an alternative co-adsorbent to deoxycholic acid (DCA) in organic dye-sensitized solar cells (DSSCs). It has dual functioned effects, that is, the prevention effect of the π–π stacking of organic dye molecules like DCA and the light harvesting effect at shorter-wavelength regions. When the HC-Acid was used as the co-adsorbent onto the TiO2 surface with the organic dye NKX2677 sensitized solar cell, an ext

This perspective thoroughly explores the energy loss factors in DSSCs and estimates the feasible efficiency of DSSCs under outdoor and indoor conditions, and compares it with the SQ limit of an ideal solar cell.

Zn(II)-porphyrin dyes (<b>SGT-030</b> and <b>SGT-031</b>) with extended auxiliary π-spacers in the donor (D) part have been prepared and applied to dye-sensitized solar cells (DSSCs). The porphyrin dyes contained the same D-ethynyl-zinc porphyrinyl (<b>ZnP</b>)-ethynyl-benzothiadiazole-acceptor platform, but their donor groups varied from phenylene (<b>Ph</b>) in <b>SGT-053</b> as a reference dye to the thieno[3,2-<i>b</i>]benzothiophene (<b>TBT</b>) and 4-hexyl-4<i>H</i>-thieno[3,2-<i>b</i>]ind