| Abstract
| - This review summarizes recent progress in the development of n-channel organic semiconductors for organic thin film transistors and discusses the critical properties that any prospective n-channel material must have. Methods important to semiconductor design such as electronic structure calculations and synthetic structural modifications are highlighted in a case study of the semiconductor molecule shown here.
- The development of new organic semiconductors with improved performance in organicthin film transistors (OTFTs) is a major challenge for materials chemists. There is aparticular need to develop air-stable n-channel (electron-conducting) organic semiconductorswith performance comparable to that of p-channel (hole-conducting) materials, for organicelectronics to realize the benefits of complementary circuit design, i.e., the ability to switchtransistors with either positive or negative gate voltages. There have been significantadvancements in the past five years. In terms of standard OTFT metrics such as the fieldeffect mobility (μFET) and on-to-off current ratio (ION/IOFF), n-channel OTFTs have achievedperformance comparable both to that of n-channel amorphous silicon TFTs and to that ofthe best reported p-channel (hole-conducting) OTFTs; however, issues of device stabilitylinger. This review provides a detailed introduction to OTFTs, summarizes recent progressin the development of new n-channel organic semiconductors, and discusses the criticalproperties that any prospective n-channel material must have. Methods important tosemiconductor design such as electronic structure calculations and synthetic structuralmodifications are highlighted in a case study of the development of a new n-channel materialbased on a terthiophene modified with electron-withdrawing groups. The review concludeswith a discussion of directions for future work in this area.
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