King-Young Wong

Blocking reactions between indium-tin oxide and poly (3,4-ethylene dioxythiophene):poly(styrene sulphonate) with a self-assembly monolayer

In the fabrication of polymeric electroluminescent devices with indium-tin oxide (ITO) as anode, indium contamination of the polymers can greatly degrade the device performance. In the present study, we have used x-ray photoelectron spectroscopy to measure indium incorporation in poly(3,4-ethylene dioxythiophene):poly(styrene sulphonate), referred to as PEDOT:PSS, which were spincast on bare ITO and encapsulated ITO. We found that the deposition of a self-assembled monolayer of alkylsiloxanes on ITO prior to spincasting PEDOT:PSS was effective and practical in blocking the reactions between ITO and PEDOT:PSS.

Highly efficient inverted organic solar cells using amino acid modified indium tin oxide as cathode

In this paper, we report that highly efficient inverted organic solar cells were achieved by modifying the surface of indium tin oxide (ITO) using an amino acid, Serine (Ser). With the modification of the ITO surface, device efficiency was significantly enhanced from 0.63% to 4.17%, accompanied with an open circuit voltage (Voc) that was enhanced from 0.30 V to 0.55 V. Ultraviolet and X-ray photoelectron spectroscopy studies indicate that the work function reduction induced by the amino acid modification resulting in the decreased barrier height at the ITO/organic interface played a crucial role in the enhanced performances.

Effects of cathode modification using spin-coated lithium acetate on the performances of polymer bulk-heterojunction solar cells

In this report, we show that the performances of polymer bulk-heterojunction solar cells were improved by inserting thin films of lithium acetate layers between the active layer and the cathode using a spin-coating process. Comparing with the device without the cathode modification, significant enhancements of Voc (open circuit voltage) from 0.42 V to 0.55 V and device efficiency from 1.4% to 4.1% were achieved. X-ray and ultraviolet photoelectron spectroscopic studies indicate that both the improved damage tolerance of the active layer under the thermally evaporated metal and an n-type doping at the metal/organic interface play the crucial roles in the enhanced performances.

Full color polymer light-emitting diodes with photo-patterning process

Full-color polymer light-emitting diode (PLED) arrays presently are mainly produced by ink-jet printing. Here, we report a new approach for fabricating full-color PLED arrays that takes advantage of the low-cost and high throughput spin-coating and photo-patterning processes. Compared to previous approaches that also employed photo-patterning, our approach does not require wet processing steps, and the spectra of the colors emitted are not sensitive to the photopatterning time. Because the photo-pattering is a traditional technology which was proved to be successfully used in producing liquid crystal displays and other electrical productions, this method may provide a low-cost and high throughput procedure to manufacture polymeric flat-panel display devices.