High Performance, Solution-Processed Organic Thin-Film Transistors from a Novel Pentacene Precursor

In the last decade considerable effort has been directed toward the design and synthesis of organic molecules to replace existing amorphous silicon in electronic devices, such as flat-panel displays. The primary interest for using organic materials is their potential for low-cost, large-area applications using solution-based deposition techniques. There has been much effort in search of soluble, high performance organic semiconductors. Among organic compounds, pentacene has been shown to have the best combination of high mobility, matching that of a-Si, high current modulation and environmental stability. The drawback for pentacene is its very low solubility in organic solvents. Here, we report the synthesis of a soluble precursor of pentacene that is formed in a high-yield, one step Diels-Alder reaction. The precursor undergoes solid phase conversion back to pentacene at moderate temperatures. We also report fabrication of thin film transistors using pentacene formed from the solution cast adduct. These organic thin film transistors have shown very high mobility (up to 0.8 cm 2 V -1 s -1 ) and greater than 10 6 current modulation. Furthermore, like TFTs fabricated from vacuum deposited pentacene, they are environmentally stable. This approach promises easy access to solution processable, high performance pentacene TFTs an important step toward realizing the goal of replacing a-Si with organic semiconductors.