Jing-Yi Yan

Enhanced Performance of Benzothieno[3,2‐b]thiophene (BTT)‐Based Bottom‐Contact Thin‐Film Transistors

Three new benzothieno[3,2-b]thiophene (BTT; 1) derivatives, which were end-functionalized with phenyl (BTT-P; 2), benzothiophenyl (BTT-BT; 3), and benzothieno[3,2-b]thiophenyl groups (BBTT; 4; dimer of 1), were synthesized and characterized in organic thin-film transistors (OTFTs). A new and improved synthetic method for BTTs was developed, which enabled the efficient realization of new BTT-based semiconductors. The crystal structure of BBTT was determined by single-crystal X-ray diffraction. Within this family, BBTT, which had the largest conjugation of the BTT derivatives in this study, exhibited the highest p-channel characteristic, with a carrier mobility as high as 0.22 cm(2)  V(-1)  s(-1) and a current on/off ratio of 1×10(7) , as well as good ambient stability for bottom-contact/bottom-gate OTFT devices. The device characteristics were correlated with the film morphologies and microstructures of the corresponding compounds.

58.1: A 4.1-Inch Flexible QVGA AMOLED Using a Microcrystalline-Si:H TFT on a Polyimide Substrate

A 4.1-inch flexible QVGA AMOLED display with microcrystalline silicon (μc-Si:H) TFTs backplane on colorless polyamide (PI) substrate is demonstrated. The PI substrate has the features of high Tg (∼350°C) and high light transmittance (∼90%). The bottom-gate μc-Si:H TFTs backplane is fabricated at 200°C by a conventional (13.56 MHz) plasma-enhanced chemical vapor deposition (PECVD) system. The flexible μc-Si:H TFTs backplane shows better electrical stability, flexibility, and uniformity.

Enhanced performance of solution-processed TESPE-ADT thin-film transistors.

A solution-processed anthradithiophene derivative, 5,11-bis(4-triethylsilylphenylethynyl)anthradithiophene (TESPE-ADT), is studied for use as the semiconducting material in thin-film transistors (TFTs). To enhance the electrical performance of the devices, two different kinds of solution processing (spin-coating and drop-casting) on various gate dielectrics as well as additional post-treatment are employed on thin films of TESPE-ADT, and p-channel OTFT transport with hole mobilities as high as ~0.12 cm(2) V(-1) s(-1) are achieved. The film morphologies and formed microstructures of the semiconductor films are characterized in terms of film processing conditions and are correlated with variations in device performance.

43.3: A Novel Flexible AMOLED with Touch Based on Flexible Universal Plane for Display Technology

A flexible thin film transistor (TFT) backplane, OLED, and the flexible projective capacitive touch sensing film were successfully developed and integrated with colorless and transparent Polyimide (PI) substrate for the first flexible touch AMOLED display based on the flexible universal plane for display (FlexUPD) technology. This unique substrate handling technology is not only compatible with the current TFT manufacturing facilities but also allows us to use the same design rule of TFT backplane as that on the glass.

65.3: 3.1-Inch Flexible Top-Emitting AMOLED on Plastic Substrate Driven by Organic Thin Film Transistors

A 3.1-inch flexible active matrix OTFT-OLED display had been demonstrated on the plastic substrate with process temperature below 200°C. To realize the flexible AMOLED, we replace ITO by Ag and develop surface control method to achieve high uniformity OTFT array and the lifetime of half Id is over 5000hrs.

Performance of Organic Thin-Film Transistors Controlled by Electrode and Device Structures

We have fabricated organic thin-film transistors (OTFTs) of top contact (TC) structures using silver electrode based on triethylsilylethynyl anthradithiophene (TES-ADT) with mobility above 0.41 cm2 s-1 V-1, current modulation higher than 5 times 107 and sub-threshold swing below 0.65 V/dec. The electrical characteristics of OTFTs are not only corresponding to the work function of source and drain electrodes materials but also to the surface tension and deposition energy of them. The effects of work function and surface tension dominate the electrical characteristics in bottom contact (BC) device. On the other hand, TC device is affected by deposition energy dominantly.

P‐21: Stability and Integrability Evaluation of Organic Thin Film Transistor with Solution Processable Semiconductor

We demonstrate Organic thin film transistors (OTFTs) with solution-processed semiconductor, triethylsilylethynyl anthradithiophene (TES-ADT), as the active layer materials are investigated. Bottom-gate solution-processed TES-ADT OTFTs possess excellent performance with mobility of 0.05 cm2V−1s−1, current modulation of 4×106, sub-threshold slope of 0.91 V/dec. and threshold voltage of −7.7 V on glass substrate. The reliability of device is evaluated and demonstrates good electrical performance uniformity and stability after bias stress. Particularly, the devices exhibit reversible degradation after vacuum annealing, shown its environmental stability under air atmosphere. Moreover, the device integrability has been demonstrated with two transistors-one capacitor (2T1C) array for display media driving such as organic light emitting diode (OLED).

A novel structure of directly patterned isolating layer for organic thin-film transistor-driven organic light emitting diodes

Mono-chrome phosphorescence Organic light emitting diodes (OLEDs) operated by organic thin-film transistors (OTFTs) with a 32×32 array are fabricated with a novel method, and the results reveal a fabulous demonstration. The later isolation, which segregated source/drain electrodes and an OLED cathode, was designed in our OTFT-OLED pixel. In the OTFT-OLED process; we used the polymer isolating layer which was deposited by spin coating and patterned by traditional photo-lithography before the organic semiconductor and OLED deposition. However, the residue polymer affect of OTFT electric properties which have poor mobility (5×10-4 cm2/V-s), a lower on/off ratio (~103), and a positive threshold voltage (4.5 V), and devices, have poor uniformity. Using UV-Ozone treatment could enhance OTFT mobility (2×10-2 cm2/V-s) and permit higher devices uniformity, but the threshold voltage would still have a positive 5.1 V. This threshold voltage was not a good operation mode for display application because this operation voltage was not fit for our driving systems. In order to overcome this problem, a new structure of OTFT-OLED pixel was designed and combined with a new-material isolating layer process. This new process could fabricate an OTFT-OLED array successfully and have a nice uniformity. After the isolating layer process, OTFT devices have a higher mobility (0.1×10-2 cm2/V-s), a higher on-off ratio (~107) a lower threshold voltage (-9.7 V), and a higher devices uniformity.