Jaeyoung Jang

Abstract The preparation of uniform large‐area highly crystalline organic semiconductor thin films that show outstanding carrier mobilities remains a challenge in the field of organic electronics, including organic field‐effect transistors. Quantitative control over the drying speed during dip‐coating permits optimization of the organic semiconductor film formation, although the kinetics of crystallization at the air–solution–substrate contact line are still not well understood. Here, we report

Photoresponsive transistor memories that can be erased using light-only bias are of significant interest owing to their convenient elimination of stored data for information delivery. Herein, we suggest a strategy to improve light-erasable organic transistor memories, which enables fast "photoinduced recovery" under low-intensity light. CdSe quantum dots (QDs) whose surfaces are covered with three different organic molecules are introduced as photoactive floating-gate interlayers in organic tran

Crystalline silicon-based complementary metal-oxide-semiconductor transistors have become a dominant platform for today's electronics. For such devices, expensive and complicated vacuum processes are used in the preparation of active layers. This increases cost and restricts the scope of applications. Here, we demonstrate high-performance solution-processed CdSe nanocrystal (NC) field-effect transistors (FETs) that exhibit very high carrier mobilities (over 400 cm(2)/(V s)). This is comparable t

Abstract Molecular doping is essential for improving the thermoelectric properties of conjugated polymers, but dopants of low solubility either restrict the formation of high quality films or complicate fabrication steps. Although a highly soluble molecular dopant, tris(pentafluorophenyl)borane (BCF), has been sporadically studied, its potential has not yet been fully explored. Herein, particularly intriguing effects of Brønsted acid doping with BCF‐water complexes for poly(3‐hexylthiophene) (P3

We report on the temperature-dependent Hall effect characteristics of nanocrystal (NC) arrays prepared from colloidal InAs NCs capped with metal chalcogenide complex (MCC) ligands (In2Se4(2-) and Cu7S4(-)). Our study demonstrates that Hall effect measurements are a powerful way of exploring the fundamental properties of NC solids. We found that solution-cast 5.3 nm InAs NC films capped with copper sulfide MCC ligands exhibited high Hall mobility values over 16 cm(2)/(V s). We also showed that th

Abstract A novel application of ethylene‐norbornene cyclic olefin copolymers (COC) as gate dielectric layers in organic field‐effect transistors (OFETs) that require thermal annealing as a strategy for improving the OFET performance and stability is reported. The thermally‐treated N , N′ ‐ditridecyl perylene diimide (PTCDI‐C13)‐based n‐type FETs using a COC/SiO 2 gate dielectric show remarkably enhanced atmospheric performance and stability. The COC gate dielectric layer displays a hydrophobic s

Abstract Self‐healable and stretchable energy‐harvesting materials can provide a new avenue for the realization of self‐powered wearable electronics, including electronic skins, whose main materials are required to be robust to and stable under external damage and severe mechanical stresses. However, thermoelectric (TE) materials showing both self‐healing properties and stretchability have not yet been demonstrated despite their great potential to harvest thermal energy in the human body. As mos

Organic thermoelectric (TE) materials have great potential as sustainable energy sources for powering flexible and wearable electronic devices via harvesting of human body heat. Recent advances in soluble conjugated polymer/carbon nanotube (CNT) composites have facilitated achievement of high TE power factors. However, the effects of conjugated polymers on the debundling and electrical percolation of CNTs and on the TE properties of their composites are not yet fully understood. Herein, we intro

We have fabricated organic field-effect transistors (OFETs) and inverters using photocrosslinkable poly(vinyl cinnamate) (PVCN) as a gate dielectric. The photocrosslinked PVCN dielectric film has superior insulating properties and does not require thermal curing. The high water resistance of the dielectric, which arises because PVCN is hydroxyl group-free, means that the devices were found to be hysteresis-free in all operations. The OFETs with the PVCN dielectric were found to exhibit a carrier

Here we describe the use of photocurable poly(vinyl cinnamate) (PVCN) as a gate dielectric in high-performance cylindrical organic field-effect transistors (OFETs) with high bending stability. A smooth-surface metallic fiber (Al wire) was employed as a cylindrical substrate, and polymer dielectrics (PVCN and poly(4-vinyl phenol) (PVP)) were formed viadip-coating. The PVCN and PVP dielectrics deposited on the Al wire and respectively cross-linked via UV irradiation and thermal heating were found

Organic-inorganic hybrid CH₃NH₃PbBr₃ (MAPbBr₃) perovskite quantum dots (PQDs) are considered as promising and cost-effective building blocks for various optoelectronic devices. However, during centrifugation for the purification of these PQDs, commonly used polar protic and aprotic non-solvents (e.g., methanol and acetone) can destroy the nanocrystal structure of MAPbBr₃ perovskites, which will significantly reduce the production yields and

Abstract Despite excellent electrical and mechanical properties, practical application of poly(3,4‐ethylenedioxythiophene) polymerized with poly(4‐styrenesulfonate) (PEDOT:PSS) face the challenge of ensuring air stability in electronic industry. Here, degradation mechanism of PEDOT:PSS‐based films in air is clearly demonstrated through X‐ray/ultraviolet photoelectron spectroscopy (XPS/UPS) and its depth‐profiling technique. As the duration of air‐exposure increases, the PEDOT:PSS‐based films alt