Sungkyunkwan University · Engineering
Professor Heeyeop Chae's research lab specializes in the development of advanced nanomaterials and optoelectronic devices, with a primary focus on quantum dot-based light-emitting diodes (QLEDs) and flexible energy storage systems. The lab explores solution-processed semiconductor nanostructures, particularly InP-based quantum dots, for high-efficiency and stable optoelectronic applications, while also advancing device architectures through innovative charge transport engineering. Additionally, the lab investigates 3D graphene-based nanostructures for next-generation flexible supercapacitors with exceptional mechanical robustness and electrochemical performance. Their work bridges materials synthesis, device physics, and practical applications in sustainable lighting and wearable electronics.
Figures are computed from collected data and may differ slightly.
Quantum dots (QDs) are being highlighted in display applications for their excellent optical properties, including tunable bandgaps, narrow emission bandwidth, and high efficiency. However, issues with their stability must be overcome to achieve the next level of development. QDs are utilized in display applications for their photoluminescence (PL) and electroluminescence. The PL characteristics of QDs are applied to display or lighting applications in the form of color-conversion QD films, and
In this work, we developed a charge control sandwich structure around QD layers for the inverted QLEDs, the performance of which is shown to exceed that of the conventional QLEDs in terms of the external quantum efficiency (EQE) and the current efficiency (CE). The QD light-emitting layer (EML) is sandwiched with two ultrathin interfacial layers: one is a poly(9-vinlycarbazole) (PVK) layer to prevent excess electrons, and the other is a polyethylenimine ethoxylated (PEIE) layer to reduce the hol
Fabrication of a multilayered quantum dot-light-emitting diode (QLED) with an inverted architecture cannot be usually fully solution-processed mainly due to the significant destruction of the pre-existing quantum dot (QD) emitting layer (EML) occurring during the subsequent solution-deposition of the hole transport layer (HTL).
In this study, multishelled InP-based quantum dots (QDs) were synthesized using a phosphorus source tris(dimethylamino)phosphine [(DMA)3P] and were applied to solution-processed QD light-emitting diode (QLED) devices. (DMA)3P is not only a safe phosphorus source but is also a low-cost precursor for InP QDs. The quantum yield of the QDs increased from 71.0 to 81.8% by post-treatment with hexanethiol. The efficiency of the (DMA)3P-based red InP QLEDs was enhanced by using chlorine-doped ZnMgO (Cl-
A flexible supercapacitor was demonstrated with ‘graphene forest’ as electrodes. No capacitance loss was observed even with 100 000 times of bending.
Vertically oriented graphene (VG) with three-dimensional architecture has been proved to exhibit unique properties, and its particular morphology has been realized by researchers to be crucial for its performance in practical applications. In this study, we investigated the morphology evolution of VG films synthesized by the plasma-enhanced chemical vapor deposition process, including porous graphene film, graphene wall, and graphene forest. This study reveals that the morphology of VG is contro
Abstract Thiophenol derivatives having a negative dipole moment such as thiophenol (TP), 4‐methylthiophenol (4‐MTP), and 4‐(dimethylamino)thiophenol (4‐DMATP) are incorporated into quantum dots (QDs) and the efficiency of all‐solution‐processed inverted‐structure quantum dot light‐emitting diodes (QLEDs) is enhanced. The negative dipole moments of TP, 4‐MTP, and 4‐DMATP are attributed to the enhancement of the efficiency of the QLEDs. The valence band maximum (VBM) of the QDs is upshifted, and t
A high current density obtained in a limited, nanometer-thick region is important for high efficiency polymer solar cells (PSCs). The conversion of incident photons to charge carriers only occurs in confined active layers; therefore, charge-carrier extraction from the active layer within the device by using solar light has an important impact on the current density and the related to power conversion efficiency. In this study, we observed a surprising result, that is, extracting the charge carri
Oxide etching yield has been measured directly with inductively coupled fluorocarbon plasmas. The yields measurement technique of this work can provide useful information for feature profile evolution modeling, which is essential to understand various issues in oxide etching such as reactive ion etching (RIE) lag, inverse RIE lag, etch stop, microtrenching, bowing, etc. Etching and deposition yields per ion were measured using quartz crystal microbalance (QCM) as a function of ion bombardment en
In this study, the plasmas of C4H3F7O fluoro-ether and fluoro-alcohol isomers of CF3CF2CF2OCH3 (HFE-347mcc3), (CF3)2CFOCH3 (HFE-347mmy), and CF3CF2CF2CH2OH (PPC) with low global warming potentials (GWPs) were characterized for etching SiO2, Si3N4, and poly-Si films. The C4H3F7O isomers have a short lifetime (<5 years) and low GWP (<1000) compared to the widely used C4F8, with a lifetime of 3200 years and a GWP100 of 10,592. Radicals in the plasma of C4H3F7O fluoro-ethers and fluoro-alcohol isome
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