Browsing by Author "Huang, Deng-Yi"

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High performance solution-processable tetrathienoacene (TTAR) based small molecules for organic field effect transistors (OFETs)
(2017-05-28)
Vegiraju, Sureshraju
;
Huang, Deng-Yi
;
Priyanka, Pragya
;
Li, Yo-Shan
;
Luo, Xian-Lun
Three new organic semiconductors with alkyl chain-substituted tetrathienoacene (TTAR) as the central core and both ends capped with thiophene (DT-TTAR), thienothiophene (DTT-TTAR) and dithienothiophene (DDTT-TTAR) have been synthesized and characterized for organic field effect transistor (OFET) applications. A hole mobility of 0.81 cm(2) V-1 s(-1) was achieved for the DDTT-TTAR film, which represents the highest mobility yet found for a solution-processable p-type TTAR-based small molecular semiconductors.
Intramolecular Locked Dithioalkylbithiophene-Based Semiconductors for High-Performance Organic Field-Effect Transistors
(2017-09-20)
Vegiraju, Sureshraju
;
Chang, Bo-Chin
;
Priyanka, Pragya
;
Huang, Deng-Yi
;
Wu, Kuan-Yi
New 3,3-dithioalkyl-2,2-bithiophene (SBT)-based small molecular and polymeric semiconductors are synthesized by end-capping or copolymerization with dithienothiophen-2-yl units. Single-crystal, molecular orbital computations, and optical/electrochemical data indicate that the SBT core is completely planar, likely via S(alkyl)S(thiophene) intramolecular locks. Therefore, compared to semiconductors based on the conventional 3,3-dialkyl-2,2-bithiophene, the resulting SBT systems are planar (torsional angle <1 degrees) and highly -conjugated. Charge transport is investigated for solution-sheared films in field-effect transistors demonstrating that SBT can enable good semiconducting materials with hole mobilities ranging from approximate to 0.03 to 1.7 cm(2) V-1 s(-1). Transport difference within this family is rationalized by film morphology, as accessed by grazing incidence X-ray diffraction experiments.
Solution-Processed High-Performance Tetrathienothiophene-Based Small Molecular Blends for Ambipolar Charge Transport
(2018-07-11)
Vegiraju, Sureshraju
;
Lin, Chih-Yu
;
Priyanka, Pragya
;
Huang, Deng-Yi
;
Luo, Xian-Lun
Four soluble dialkylated tetrathienoacene (TTAR)-based small molecular semiconductors featuring the combination of a TTAR central core, pi-conjugated spacers comprising bithiophene (bT) or thiophene (T), and with/without cyanoacrylate (CA) end-capping moieties are synthesized and characterized. The molecule DbT-TTAR exhibits a promising hole mobility up to 0.36 cm(2) V-1 s(-1) due to the enhanced crystallinity of the microribbon-like films. Binary blends of the p-type DbT-TTAR and the n-type dicyanomethylene substituted dithienothiophene-quinoid (DTTQ-11) are investigated in terms of film morphology, microstructure, and organic field-effect transistor (OFET) performance. The data indicate that as the DbT-TTAR content in the blend film increases, the charge transport characteristics vary from unipolar (electron-only) to ambipolar and then back to unipolar (hole-only). With a 1:1 weight ratio of DbT-TTAR DTTQ-11 in the blend, well-defined pathways for both charge carriers are achieved and resulted in ambipolar transport with high hole and electron mobilities of 0.83 and 0.37 cm(2) V-1 s(-1), respectively. This study provides a viable way for tuning microstructure and charge carrier transport in small molecules and their blends to achieve high-performance solution-processable OFETs.