Abstract A hybrid Cartesian/immersed boundary code is developed and applied to interactions between a flexible plate and a surrounding fluid. The velocities at the immersed boundary (IB) nodes are reconstructed by interpolations along local normal lines to an interface. A new criterion is suggested to distribute the IB nodes near an interface. The suggested criterion guarantees a closed fluid domain by a set of the IB nodes and it is applicable to a zero‐thickness body. To eliminate the pressure interpolation at the IB nodes, the hybrid staggered/non‐staggered grid method is adapted. The developed code is validated by comparisons with other experimental and computational results of flow around an in‐line oscillating cylinder. Good agreements are achieved for velocity profiles and vorticity and pressure contours. As applications to the fluid–structure interaction, oscillations of flexible plate in a resting fluid and flow over a flexible plate are simulated. The elastic deformations of the flexible plate are modelled based on the equations of motion for plates considering the fluid pressure as the external load on the plate. Two non‐dimensional parameters are identified and their effects on the damping of the plate motion are examined. Grid convergence tests are carried out for both cases. Copyright © 2007 John Wiley & Sons, Ltd.

Regular grid

Immersed Boundary Method

Interpolation

Fluid–structure interaction

10.1002/fld.1459

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Citations (24)

Guanidinium-Pseudohalide Perovskite Interfaces Enable Surface Reconstruction of Colloidal Quantum Dots for Efficient and Stable Photovoltaics

ACS Nano (2022)

Jonghee Yang Seong Chan Cho Seungjin Lee Jung Won Yoon Woo Hyeon Jeong

Complete surface passivation of colloidal quantum dots (CQDs) and their strong electronic coupling are key factors toward high-performance CQD-based photovoltaics (CQDPVs). Also, the CQD matrices must be protected from oxidative environments, such as ambient air and moisture, to guarantee air-stable operation of the CQDPVs. Herein, we devise a complementary and effective approach to reconstruct the oxidized CQD surface using guanidinium and pseudohalide. Unlike conventional halides, thiocyanate anions provide better surface passivation with effective replacement of surface oxygen species and additional filling of defective sites, whereas guanidinium cations promote the construction of epitaxial perovskite bridges within the CQD matrix and augment electronic coupling. Additionally, we replace a defective 1,2-ethanedithiol-treated CQD hole transport layer (HTL) with robust polymeric HTLs, based on a judicious consideration of the energy level alignment established at the CQD/HTL interface. These efforts collectively result in high-performance and stable CQDPVs with photocurrents over 30 mA cm-2, ∼80% quantum efficiency at excitonic peaks and stable operation under humid and ambient conditions. Elucidation of carrier dynamics further reveals that interfacial recombination associated with band alignment governs both the CQDPV performance and stability.

Passivation

10.1021/acsnano.1c10636

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Citations (25)

Charge‐Selective, Narrow‐Gap Indium Arsenide Quantum Dot Layer for Highly Stable and Efficient Organic Photovoltaics

Advanced Energy Materials (2022)

Youngsang Park Sung Yong Bae Tae‐Wan Kim Seongmin Park Jae Taek Oh

Abstract The past decade has seen a dramatic surge in the power conversion efficiency (PCE) of next‐generation solution‐processed thin‐film solar cells rapidly closing the gap in PCE of commercially‐available photovoltaic (PV) cells. Yet the operational stability of such new PVs leaves a lot to be desired. Specifically, chemical reaction with absorbers via high‐energy photons transmitted through the typically‐adapted metal oxide electron transporting layers (ETLs), and photocatalytic degradation at interfaces are considered detrimental to the device performance. Herein, the authors introduce a device architecture using the narrow‐gap, Indium Arsenide colloidal quantum dots (CQDs) with discrete electronic states as an ETL in high‐efficiency solution‐processed PVs. High‐performing PM6:Y6 organic PVs (OPVs) achieve a PCE of 15.1%. More importantly, as the operating stability of the device is significantly improved, retaining above 80% of the original PCE over 1000 min under continuous illumination, a Newport‐certified PCE of 13.1% is reported for nonencapsulated OPVs measured under ambient air. Based on operando studies as well as optical simulations, it suggested that the InAs CQD ETLs with discrete energy states effectively cut‐off high‐energy photons while selectively collecting electrons from the absorber. The findings of this works enable high‐efficiency solution‐processed PVs with enhanced durability under operating conditions.

Indium arsenide

Quantum Efficiency

Indium tin oxide

10.1002/aenm.202104018

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Citations (20)

Improving the charge transport of perovskite nanocrystal light-emitting-diodes through Benzylammonium ligand exchange

Applied Surface Science Advances (2025)

Min-Sik Gong Dong Gyu Lee Gwang Yong Shin Yun Seop Shin Donghwan Yun

10.1016/j.apsadv.2025.100698

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Citations (0)

Molecular aggregation method for perovskite–fullerene bulk heterostructure solar cells

Journal of Materials Chemistry A (2019)

Su Ryong Ha Woo Hyeon Jeong Yanliang Liu Jae Teak Oh Sung Yong Bae

We report morphological control with phenyl-C60-butyric acid methyl ester (PCBM) molecular aggregation for perovskite–PCBM bulk heterostructure (Pe–PCBM BHS) solar cells.

10.1039/c9ta11854c

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Citations (17)

Simulation of water entry of an elastic wedge using the FDS scheme and HCIB method

Journal of Hydrodynamics (2013)

Sangmook Shin Sung Yong Bae

Wedge (geometry)

10.1016/s1001-6058(11)60384-4

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Citations (11)

Ecofriendly AgBiS₂ Nanocrystal Photoanode for Highly Efficient Visible-Light-Driven Photoelectrochemical Water Splitting

ACS Applied Energy Materials (2023)

Taiho Park Gisang Park Sung Yong Bae Hae Jeong Kim Duck Hoon Lee

Photoelectrochemical (PEC) hydrogen production via water splitting is a promising sustainable energy conversion method. However, most semiconductors used as photoanodes in PEC splitting exhibit several drawbacks, including ultraviolet (UV)-limited activity, toxic components, and complicated material processing. To address these issues, this study presents a photoanode design strategy for visible-light-driven PEC water splitting in aqueous Na2SO4 solution using a solution-processable AgBiS2 nanocrystal (NC) photoanode. It was observed that the characteristics of the ligand used for the AgBiS2 NC photoanode are crucial in determining its PEC water splitting performance. Moreover, the thiol ligand-capped AgBiS2 NC photoanode shows a higher photocurrent density (Jph) in both 1 sun and visible light than typical TiO2 or Bi2S3 NC photoanodes owing to its excellent electron collection ability and low interfacial charge transfer resistance. The AgBiS2 NC photoanode emits 91% of Jph under visible and near-IR light, whereas the Bi2S3 NC photoanodes exhibited a Jph of 67% under the same conditions, demonstrating the superiority of AgBiS2 NC materials for application in highly efficient visible-light-driven PEC devices.

Photocurrent

Visible spectrum

Photoelectrochemical cell

10.1021/acsaem.3c00040

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Citations (3)