Origin of Bias-Stress Induced Instability in Organic Thin-Film Transistors with Semiconducting Small-Molecule/Insulating Polymer Blend Channel

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• 作者：Ji Hoon Park ; Young Tack Lee ; Hee Sung Lee ; Jun Young Lee ; Kimoon Lee ; Gyu Baek Lee ; Jiwon Han ; Tae Woong Kim ; Seongil Im
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2013
• 出版时间：March 13, 2013
• 年：2013
• 卷：5
• 期：5
• 页码：1625-1629
• 全文大小：356K
• 年卷期：v.5,no.5(March 13, 2013)
• ISSN：1944-8252

文摘

The stabilities of a blending type organic thin-film transistor with phase-separated TIPS-pentacene channel layer were characterized under the conditions of negative-bias-stress (NBS) and positive-bias-stress (PBS). During NBS, threshold voltage (V_th) shifts noticeably. NBS-imposed devices revealed interfacial trap density-of-states (DOS) at 1.56 and 1.66 eV, whereas initial device showed the DOS at only 1.56 eV, as measured by photoexcited charge-collection spectroscopy (PECCS) method. Possible origin of this newly created defect is related to ester group in PMMA, which induces some hole traps at the TIPS-pentacene/i-PMMA interface. PBS-imposed device showed little V_th shift but visible off-current increase as 鈥渂ack-channel鈥?effect, which is attributed to the water molecules trapped on the TFT surface.

Keywords:

TIPS-pentacene; blend; stability; bias-stress; photoexcited charge collection spectroscopy (PECCS); scanning kelvin probe microscopy (SKPM)