Jung-An Cheng

Rib-free Ink-Jet Printing Fabrication on Heterogeneous Surfaces

Rib-free ink-jet printing device fabrication on hetrogeneous surfaces opens a new possibility for greener processes. The integrity of ink droplets was maintained with less than 3° contact angle differences on the heterogeneous surfaces after surface treatment. The breaking of color lines and color mixing were avoided by accelerating solvent evaporation. The inks were greatly conserved without the need for additional lithography process for rib structure.

Enhanced field-effect mobility in pentacene based organic thin-film transistors on polyacrylates

We reported on organic thin-film transistors (OTFTs) with high dielectric constant polymer, poly(2,2,2-trifluoroethyl methacrylate) (PTFMA), as the gate dielectric. In top-contact OTFTs, the field-effect mobility was enhanced by applying a dielectric buffer layer poly(α-methylstyrene) to the bare PTFMA. After improving interfacial affinity within the active layer/dielectrics, deposited pentacene grain size and device performance were enhanced dramatically. The corresponding mobility, threshold voltage, and on/off current ratio were 0.70 cm2 V−1 s−1, −10.5 V, and 5.4×105, respectively. The moderately improved interface also suppressed the hole-trapping effect, which led to less hysteresis and minimized threshold voltage shift.

Organic thin-film transistors with color filtering functional gate insulators

We developed color filtering functional organic thin-film transistors exhibiting both high field-effect mobilities and color-filtering ability. The conventional colorant inks were utilized as the materials for the color filter/dielectric multifunction layers. In order to improve the electrical performance, a high dielectric polymeric insulator, poly(2,2,2-trifluoroethyl methacrylate), was introduced to modify the surface of the dielectric layer. Further, the Commission Internationale de L’Eclairage chromaticity coordinates were (0.64, 0.34), (0.36, 0.54), and (0.14, 0.15) for red, green, and blue devices, respectively, covering 49.2% National Television Systems Committee standard. This work represents one potential example for multifunctional organic electronics.

P‐179: A Novel Pixel Structure for the Emiflective Hybrid Display System

A novel hybrid display pixel structure is proposed. This pixel structure consists of organic light-emitting diodes (OLEDs) and reflective liquid crystal displays to form an emi-flective display. With a single pixel circuit and proper driving method, the pixel circuit can drive LC cells and OLEDs in one display system. Moreover, a compatible fabrication process of the hybrid device has been examined. By utilizing the reflective LCD, the wash-out phenomenon of OLED under bright ambient light can be compensated.

P‐63: Rib‐Less Ink‐Jet‐Printed 4‐In.‐Panel Color‐Filter Fabrication

A 4 “color filter panel was successfully prepared by rib-less ink jet printing process. The smeared ink issue can be controlled by surface treatment on both Cr and glass with similar contact angle. The color line formation can be prepared by either two-step printing process at room temperature or one-step printing at elevated temperature. The thickness of red, green and blue films were about 1.2μm, 1.0μm and 1.0μm, respectively. The panels NTSC value was estimated at 53.5±0.7%.

P‐66: Large Area Color Filter Fabrication by Using Ink‐Jet Printing Technology

A novel ink jet printing process without additional photolithography process for large area color filter fabrication has been developed in this study. A 100×100 mm2 model of 32″ color filters was fabricated for evaluation. New developed RGB inks were able to achieve 73% NTSC standard with the thickness of R, G, and B films at 1.80, 1.90, and 1.80 μm, respectively. The overflow issue can be solved by surface pretreatments, and color inks formulation.

P‐10: Transparent OTFTs with Color Filtering Functional Gate Insulators

Transparent organic thin-film transistors (OTFTs) impregnated with nanoparticles, organic dyes and pigments in the dielectric insulators were fabricated and analyzed. The colored composite insulators were utilized as the color filter and the dielectric layer of the OTFTs simultaneously to obtain the desired color. It was found that the performance of the OTFTs with the above mentioned composite dielectric layers possess color filtering comparable to the conventional devices. In addition, light sensitivity of OTFTs was significantly reduced.