A5107027161- Organic Electronics and Photovoltaics
- Organic Light-Emitting Diodes Research
- Conducting polymers and applications
- Thin-Film Transistor Technologies
- Molecular Junctions and Nanostructures
- Nanowire Synthesis and Applications
- Ocular Surface and Contact Lens
- Perovskite Materials and Applications
- Microfluidic and Capillary Electrophoresis Applications
- Semiconductor materials and devices
- Luminescence and Fluorescent Materials
- Advancements in Transdermal Drug Delivery
- Advanced biosensing and bioanalysis techniques
- Diamond and Carbon-based Materials Research
- Microfluidic and Bio-sensing Technologies
- Metal and Thin Film Mechanics
- Electrostatics and Colloid Interactions
- Green IT and Sustainability
- Advanced Fiber Optic Sensors
- Advanced Memory and Neural Computing
- Polymer Nanocomposite Synthesis and Irradiation
City University of Hong Kong
2002-2025
Shanghai Jiao Tong University
2024
National University of Singapore
2008-2009
A high-performance cathode consisting of an ultrathin CsF layer and a rare-earth ytterbium (Yb) metal is reported for application in organic electroluminescent devices. Standard tris-(8-hydroxyquinoline) aluminum/α-napthylphenylbiphenyl diamine devices with this bilayer showed dramatically reduced operating voltage low turn-on 2.42 V as compared to 3.75 2.95 using, respectively, the Mg:Ag single-layer Yb cathodes. At current density 200 mA/cm2, CsF/Yb exhibited high luminance efficiency 3.45...
A multilayer structure of copper phthalocyanine/poly(3-hexylthiophene-2,5-diyl): [6,6]-phenyl-C61-butyric acid methyl ester (CuPc/P3HT:PCBM) is used to extend the light absorption spectrum covering almost entire visible spectrum. To maximize absorption, total number excitons created in as a function layer thickness both CuPc and P3HT:PCBM simulated by using optical transfer matrix formalism. The solar cells with device ITO/PEDOT:PSS/CuPc/P3HT:PCBM/Al are fabricated different layers...
The use of silicon oxy-nitride (SiOxNy) as an anode buffer layer in organic light-emitting devices (OLEDs) with a configuration indium tin oxide (ITO)/SiOxNy/α-naphtylphenyliphenyl diamine (NPB)/8-hydroxyquinoline aluminum/Mg:Ag has been studied. With SiOxNy several angstroms thick, the device efficiency increased from 3.0 to 3.8 cd/A. also protected ITO surface contamination due air exposure. Upon exposing cleaned substrate for one day before fabrication, current and turn-on voltage...
A significant increase in open circuit voltage (VOC) is obtained the polymer-fullerene bulk heterojunction solar cell by using e-beam deposited Al cathode. Compared with device thermal evaporated cathode, an obvious enhancement of VOC from 596 to 664 mV obtained, which makes overall power conversion efficiency improved 12.4% (from 3.79% 4.26%). Electrical characterizations suggest that energetic particles deposition induce deep interface hole traps poly(3-hexylthiophene-2,5-diyl) (P3HT),...
A glycerol-modified poly(3,4-ethylene dioxythiophene) (PEDOT): poly(styrene sulfonate) (PSS) layer was used as an anode buffer in polymer light-emitting devices using poly(9,9-dioctylfluorene) (F8) the emitter. Devices with a configuration of indium tin oxide/PEDOT:PSS (with or without glycerol)/F8/CsF/Al were fabricated. It found that device showed much larger current density than unmodified device. At operating voltage 6 V, luminance 1300 Cd/m2 and efficiency 1.7 Cd/A compared to...
The interaction between LiF and Al has been studied by x-ray photoemission spectroscopy high-resolution electron energy loss (HREELS). At room temperature, reaction already occurred in the presence of Alq3, as revealed 0.25 eV shift Li 1s peak relative to F peak. Upon heating LiF-coated substrate above 70 °C, also absence suggested emergence a 0.85 below original relatively large indicated that emergent state possessed metallic character. upon was corroborated HREELS measurements. Heating...
We report that an ultrathin layer of tris-(8-hydroxyquinoline) aluminum (Alq3) interposed between a bilayer cathode LiF/Al and emissive can significantly improve electroluminescence efficiency in polymer light-emitting device (PLED). At current density 35 mA/cm2, poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenyl-enevinylene] (MEH-PPV)-based PLED with Alq3/LiF/Al has quantum 2.5%, considerably higher than MEH-PPV-based bare Al or cathode. Interfacial characteristics MEH-PPV/LiF/Al...
We report that the green-emitting polymer—poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT), a copolymer of poly(9,9-dioctylfluorene) (F8), formed two distinct interfaces with calcium and cesium, respectively, as observed in photoemission measurements. Ultraviolet spectroscopy showed Ca stable interface F8BT without significantly changing electronic structure F8BT, which is contrast to Cs/F8BT where bipolaron states occurred forbidden gap result charge transfer processes. X-ray revealed...
Conducting fluorocarbon coatings (CFx) have recently been used as an anode buffer layer in organic light-emitting diode (OLEDs) for enhancement of stability and carrier injection. The effect CFx on OLEDs was related to its conductivity. We found the resistivity poorly conducting (about 1010 Ω cm) can be substantially decreased 105 cm by either near UV or Ar ion irradiation. were prepared untreated treated performance comparison. treatment improved device performance, while led deterioration....
Since ytterbium (Yb) possesses a low work function of 2.6 eV and Yb fluoride generally has high negative free energy formation, it is conceivable to use Yb, either directly or parasitically, with metal fluoride, as cathode in organic light-emitting diodes (OLEDs). In this work, the electronic structure chemistry at interface Yb/poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) were investigated by ultraviolet x-ray photoemission spectroscopy (UPS XPS, respectively). We found that...