Molecular Orientation‐Dependent Bias Stress Stability in Bottom‐Gate Organic Transistors Based on an n‐Type Semiconducting Polymer. (4th February 2016)

• Record Type: Journal Article
• Authors: Kang, Boseok; Moon, Byungho; Choi, Hyun Ho; Song, Eunjoo; Cho, Kilwon
• Is Part Of: Advanced Electronic Materials. Volume 2:Number 3(2016)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2016-02-04
• Subjects: bias stability -- molecular orientation -- organic transistors -- polymer semiconductors -- PECCS; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.201500380
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract : Despite remarkable advances in the performances of organic field‐effect transistors (OFETs) in recent years, the bias stability of OFET devices remains a critical obstacle to their commercial use. The microstructural origins of charge traps inside OFET devices are not yet clearly understood, and investigating these origins presents an important challenge. The unique electrical properties of an n ‐type semiconducting polymer, poly[[ N, N′ ‐bis(2‐octyldodecyl)‐naphthalene‐1, 4, 5, 8‐bis(dicarboximide)‐2, 6‐diyl]‐ alt ‐5, 5 ′ ‐(2, 2 ′ ‐bithiophene)] (P(NDI2OD‐T2)), are explored here to study the correlation between the microstructures of polymer semiconductor thin films and the bias stability of an OFET. It is demonstrated that although the charge carrier mobilities in a series of devices may be similar, the bias stress stabilities can differ significantly, depending on the molecular orientations of the semiconducting thin films. A higher degree of bias stress stability is attained in the P(NDI2OD‐T2) FETs prepared with face‐on thin‐film structures compared to the bias stress stability attained in the edge‐on film structures. Further experimental evidence suggests that the aliphatic alkyl chains in edge‐on‐oriented P(NDI2OD‐T2) films present a hurdle to vertical charge transport and induce large numbers of bipolarons during bias stress, in contrast with the face‐on structured thin films. Abstract : The bias stress stability in a series of organic transistors is investigated using semiconducting polymer thin films prepared with one of the two molecular orientations: face‐on or edge‐on. The experimental results demonstrate that face‐on structured thin films favored efficient charge injection, thereby suppressing bipolaron formation.