Jin-Hyuk Bae

Bio: Jin-Hyuk Bae is an academic researcher from Kyungpook National University. The author has contributed to research in topics: Thin-film transistor & Pentacene. The author has an hindex of 18, co-authored 174 publications receiving 1566 citations. Previous affiliations of Jin-Hyuk Bae include Seoul National University & Korea University.

Stable perovskite solar cells with efficiency exceeding 24.8% and 0.3-V voltage loss.

Abstract: Further improvement and stabilization of perovskite solar cell (PSC) performance are essential to achieve the commercial viability of next-generation photovoltaics. Considering the benefits of fluorination to conjugated materials for energy levels, hydrophobicity, and noncovalent interactions, two fluorinated isomeric analogs of the well-known hole-transporting material (HTM) Spiro-OMeTAD are developed and used as HTMs in PSCs. The structure-property relationship induced by constitutional isomerism is investigated through experimental, atomistic, and theoretical analyses, and the fabricated PSCs feature high efficiency up to 24.82% (certified at 24.64% with 0.3-volt voltage loss), along with long-term stability in wet conditions without encapsulation (87% efficiency retention after 500 hours). We also achieve an efficiency of 22.31% in the large-area cell.

Functional solid additive modified PEDOT:PSS as an anode buffer layer for enhanced photovoltaic performance and stability in polymer solar cells.

Abstract: Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is most commonly used as an anode buffer layer in bulk-heterojunction (BHJ) polymer solar cells (PSCs). However, its hygroscopic and acidic nature contributes to the insufficient electrical conductivity, air stability and restricted photovoltaic (PV) performance for the fabricated PSCs. In this study, a new multifunctional additive, 2,3-dihydroxypyridine (DOH), has been used in the PEDOT: PSS buffer layer to obtain modified properties for PEDOT: PSS@DOH and achieve high PV performances. The electrical conductivity of PEDOT:PSS@DOH films was markedly improved compared with that of PEDOT:PSS. The PEDOT:PSS@DOH film exhibited excellent optical characteristics, appropriate work function alignment, and good surface properties in BHJ-PSCs. When a poly(3-hexylthiohpene):[6,6]-phenyl C61-butyric acid methyl ester blend system was applied as the photoactive layer, the power conversion efficiency of the resulting PSCs with PEDOT:PSS@DOH(1.0%) reached 3.49%, outperforming pristine PEDOT:PSS, exhibiting a power conversion enhancement of 20%. The device fabricated using PEDOT:PSS@DOH (1.0 wt%) also exhibited improved thermal and air stability. Our results also confirm that DOH, a basic pyridine derivative, facilitates adequate hydrogen bonding interactions with the sulfonic acid groups of PSS, induces the conformational transformation of PEDOT chains and contributes to the phase separation between PEDOT and PSS chains.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

High-k organic, inorganic, and hybrid dielectrics for low-voltage organic field-effect transistors.

Abstract: 2.2. Interface Trapping Effects 211 3. High-k Dielectric Materials for OFETs 212 3.1. Inorganic Dielectrics 212 3.1.1. Aluminum Oxide 213 3.1.2. Tantalum Oxide 215 3.1.3. Titanium Dioxide 216 3.1.4. Hafnium Dioxide 217 3.1.5. Zirconium Dioxide 218 3.1.6. Cerium Dioxide 218 3.2. Organic Dielectrics 218 3.2.1. Polymer Dielectrics 218 3.2.2. Self-Assembled Monoand Multilayers 225 3.3. Hybrid Dielectrics 227 3.3.1. Polymeric-Nanoparticle Composites 227 3.3.2. Inorganic-Organic Bilayers 232 3.3.3. Hybrid Solid Polymer Electrolytes 235 4. Summary 235 5. Acknowledgments 236 6. References 236

Micropower energy harvesting

Abstract: More than a decade of research in the field of thermal, motion, vibration and electromagnetic radiation energy harvesting has yielded increasing power output and smaller embodiments. Power management circuits for rectification and DC-DC conversion are becoming able to efficiently convert the power from these energy harvesters. This paper summarizes recent energy harvesting results and their power management circuits.

Conformal quantum dot–SnO2 layers as electron transporters for efficient perovskite solar cells

Abstract: Improvements to perovskite solar cells (PSCs) have focused on increasing their power conversion efficiency (PCE) and operational stability and maintaining high performance upon scale-up to module sizes. We report that replacing the commonly used mesoporous–titanium dioxide electron transport layer (ETL) with a thin layer of polyacrylic acid–stabilized tin(IV) oxide quantum dots (paa-QD-SnO2) on the compact–titanium dioxide enhanced light capture and largely suppressed nonradiative recombination at the ETL–perovskite interface. The use of paa-QD-SnO2 as electron-selective contact enabled PSCs (0.08 square centimeters) with a PCE of 25.7% (certified 25.4%) and high operational stability and facilitated the scale-up of the PSCs to larger areas. PCEs of 23.3, 21.7, and 20.6% were achieved for PSCs with active areas of 1, 20, and 64 square centimeters, respectively. Description Tailoring tin oxide layers Mesoporous titanium dioxide is commonly used as the electron transport layer in perovskite solar cells, but electron transport layers based on tin(IV) oxide quantum dots could be more efficient, with a better-aligned conduction band and a higher carrier mobility. Kim et al. show that such quantum dots could conformally coat a textured fluorine-doped tin oxide electrode when stabilized with polyacrylic acid. Improved light trapping and reduced nonradiative recombination resulted in a certified power conversion efficiency of 25.4% and high operational stability. In larger-area minimodules, active areas as high as 64 square centimeters maintained certified power conversion efficiencies of more than 20%. —PDS Polymer-stabilized tin oxide nanoparticles suppress recombination at the electron-transport layer–perovskite interface.