정현석 교수

With rapid progress in a power conversion efficiency (PCE) to reach 25%, metal halide perovskite-based solar cells became a game-changer in a photovoltaic performance race. Triggered by the development of the solid-state perovskite solar cell in 2012, intense follow-up research works on structure design, materials chemistry, process engineering, and device physics have contributed to the revolutionary evolution of the solid-state perovskite solar cell to be a strong candidate for a next-generati

Perovskite solar cells based on organometal halide light absorbers have been considered a promising photovoltaic technology due to their superb power conversion efficiency (PCE) along with very low material costs. Since the first report on a long-term durable solid-state perovskite solar cell with a PCE of 9.7% in 2012, a PCE as high as 19.3% was demonstrated in 2014, and a certified PCE of 17.9% was shown in 2014. Such a high photovoltaic performance is attributed to optically high absorption c

We report annealing-free compact TiO_x layer by atomic layer deposition for high efficiency flexible perovskite solar cells, and maintained 95% of the initial PCE after 1000 bending cycles with 10 mm bending radius.

With rapid and brilliant progress in performance over recent years, perovskite solar cells have drawn increasing attention for portable power source applications.

Photoelectrochemical oxidation of water presents a pathway for sustainable production of hydrogen peroxide (H2O2). Two-electron water oxidation toward H2O2, however, competes with the popular four-electron process to form oxygen and one-electron water oxidation to form OH radical. To date, bismuth vanadate (BiVO4) has been shown to exhibit promising selectivity toward H2O2, especially under illumination, but it suffers from high overpotential and notoriously poor stability. Herein, using density

The two-electron water oxidation reaction (2e-WOR) is a promising route for distributed electrochemical synthesis of hydrogen peroxide (H2O2), an effective and green oxidizer, bleaching agent, and antiseptic. To date, the best electrocatalyst for 2e-WOR, in terms of selectivity against the competing 4e-WOR to form O2, is BiVO4. Nevertheless, BiVO4 is unstable and has a high overpotential of ∼340 mV at 0.2 mA/cm2 for 2e-WOR. Herein, we use density functional theory to identify a new, efficient, s

By employing the neutral plane concept, we demonstrated ultra-flexible perovskite solar cells that can withstand 100 cycles of crumpling.

A Nb-doped TiO 2 (NTO) thin film was deposited on a fluorine-doped tin oxide (FTO) electrode by pulsed laser deposition (PLD) and its application as a new compact layer material for dye-sensitized solar cells (DSSCs) was investigated. On the basis of the investigation of the dark current, open circuit voltage ( V oc ) decay, current−voltage ( I − V ) characteristics, and electrochemical impedance spectra (EIS), it was found that the NTO layer functioned as both a blocking layer and an ancillary

We report on reduced graphene oxide (rGO)/mesoporous (mp)-TiO2 nanocomposite based mesostructured perovskite solar cells that show an improved electron transport property owing to the reduced interfacial resistance. The amount of rGO added to the TiO2 nanoparticles electron transport layer was optimized, and their impacts on film resistivity, electron diffusion, recombination time, and photovoltaic performance were investigated. The rGO/mp-TiO2 nanocomposite film reduces interfacial resistance w

Most research on perovskite solar cells has focused on improving power-conversion efficiency and stability. However, if one could refurbish perovskite solar cells, their stability might not be a critical issue. From the perspective of cost effectiveness, if failed, perovskite solar cells could be collected and recycled; reuse of their gold electrodes and transparent conducting glasses could reduce the price per watt of perovskite photovoltaic modules. Herein, we present a simple and effective me

Sol-gel-derived Mg(OH)(2) gel was coated onto TiO(2) nanoparticles, and the subsequent thermal topotactic decomposition of the gel formed a highly nanoporous MgO crystalline coating. The specific surface area of the electrode that was prepared from the core-shell-structured TiO(2) nanoparticles significantly increased compared with that of the uncoated TiO(2) electrode. The increase in the specific surface area of the MgO-coated TiO(2) electrode was attributed to the highly nanoporous MgO coatin

The performance of dye-sensitized solar cells (DSSCs) consisting of anatase TiO 2 nanoparticles that were synthesized via a two-step sol−gel process was investigated using electron transport and optical characterizations. Spherical nanoparticles with the average diameter of 20 nm, elongated nanorods with an aspect ratio (AR) of 5, and nanowires with AR = 10 were synthesized. The synthesized nanoparticles possess narrow size distribution, high crystallinity, and negligible surface defects and res