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Gradual Controlling the Work Function of Metal Electrodes by Solution‐Processed Mixed Interlayers for Ambipolar Polymer Field‐Effect Transistors and Circuits
Author(s) -
Long Dang Xuan,
Baeg KangJun,
Xu Yong,
Kang SeokJu,
Kim MyungGil,
Lee GeonWoong,
Noh YongYoung
Publication year - 2014
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201401154
Subject(s) - ambipolar diffusion , materials science , work function , field effect transistor , semiconductor , transistor , electrode , optoelectronics , nanotechnology , electron , electrical engineering , voltage , chemistry , physics , engineering , layer (electronics) , quantum mechanics
In this paper, a technique using mixed transition‐metal oxides as contact interlayers to modulate both the electron‐ and hole‐injections in ambipolar organic field‐effect transistors (OFETs) is presented. The cesium carbonate (Cs 2 CO 3 ) and vanadium pentoixide (V 2 O 5 ) are found to greatly and independently improve the charge injection properties for electrons and holes in the ambipolar OFETs using organic semiconductor of diketopyrrolopyrrolethieno[3,2‐b]thiophene copolymer (DPPT‐TT) and contact electrodes of molybdenum (Mo). When Cs 2 CO 3 and V 2 O 5 are blended at various mixing ratios, they are observed to very finely and constantly regulate the Mo's work function from −4.2 eV to −4.8 eV, leading to high electron‐ and hole‐mobilities as high as 2.6 and 2.98 cm 2 V −1 s −1 , respectively. The most remarkable finding is that the device characteristics and device performance can be gradually controlled by adjusting the composition of mixed‐oxide interlayers, which is highly desired for such applications as complementary circuitry that requires well matched n‐channel and p‐channel device operations. Therefore, such simple interface engineering in conjunction with utilization of ambipolar semiconductors can truly enable the promising low‐cost and soft organic electronics for extensive applications.