Publications by authors named "Hee Jung Kwak"
Article Synopsis
- Thin-film thermocouple (TFTC) technology involves creating a thermocouple sensor during deposition to measure surface temperatures effectively, even on complex surfaces.
- This study focuses on optimizing the fabrication and performance of TFTC sensors for monitoring cutting temperatures during machining processes, which has yet to be fully developed in previous research.
- The research found that using a Chromel with a 9:1 nickel to chrome ratio improved resistivity and sensitivity, indicating that the B-type TFTC design is promising for detecting heat generated in cutting operations.
The energy level offset at inorganic layer-organic layer interfaces and the mismatch of hole/electron mobilities of the individual layers greatly limit the establishment of balanced charge carrier injection inside the emissive layer of halide perovskite light-emitting diodes (PeQLEDs). In contrast with other types of light-emitting devices, namely OLEDs and QLEDs, various techniques such as inserting an electron suppression layer between the emissive and electron transport layer have been employed as a means of establishing charge carrier injection into their respective emissive layers. Hence, in this study, we report the use of a thin layer of Poly(4-vinylpyridine) (PVPy) (an electron suppression material) placed between the emissive and electron transport layer of a halide PeQLEDs fabricated with an inverted configuration.
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- Achieving efficient electron transport from the electron transport layer (ETL) to the emissive layer (EML) is crucial for enhancing the performance of quantum dot light-emitting diodes (QD-LEDs).
- This study investigates how different configurations of a Poly(4-vinylpyridine) (PVPy) interlayer affect the charge injection balance and performance of red QD-LEDs made from InP materials.
- The findings suggest that a lower concentration of PVPy (0.1 mg/mL) improves device performance, while increasing this concentration leads to poorer outcomes, with the first special device design outshining the others in overall efficiency and luminance.
Effect of Optical and Morphological Control of Single-Structured LEC Device.
Micromachines (Basel)
July 2021
Article Synopsis
- Researchers studied the performance of single-structured light-emitting electrochemical cells (LECs) using a Ru(bpy)(PF) polymer composite for the emission layer, focusing on thickness and heat treatment effects.
- They found that a thickness of 150 nm offered the best balance, with improved optical properties and low surface roughness, while thicknesses below 120-150 nm or above 150 nm led to decreased performance and stability issues.
- Heat treatment at 100 °C enhanced the surface properties, resulting in stable operation and achieving a maximum luminance of 3532 cd/m and an external quantum efficiency (EQE) of 1.14% at the optimal 150 nm thickness.