Development of a Simple, Scalable, and Vacuum-Free Method to Fabricate Organic Semiconductor Single Crystals with Area Selectivity for High Performance Organic Field-Effect Transistor Applications

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K22421
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0302:Electrical and electronic engineering and related fields
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Bulgarevich Kirill 国立研究開発法人理化学研究所, 創発物性科学研究センター, 特別研究員 (60880268)
• Project Period (FY): 2020-09-11 – 2022-03-31
• Keywords: 有機トランジスタ / 単結晶優位半導体 / 大気中蒸着 / パターン化結晶成長 / 表面エネルギーパターン

Outline of Final Research Achievements

Methylthiolated pyrene at 1,3,6,8-positions (MT-pyrene) was rediscovered as a promising organic semiconductor material that crystallizes into a brickwork structure due to the four methylthio groups. Very high mobility of 30 cm2 V-1 s-1 and band-like transport were experimentally measured (selected as cover picture of Advanced Materials). Single crystal (SC) growth by microspacing sublimation (MSS) method was established for rubrene, MT-pyrene and other materials. The possibility of SC growth from liquid phase was confirmed for rubrene. The patterned SC growth with the use of hydrophobic/hydrophilic patterning was achieved for rubrene, but the obtained SCs were too small and too thick for practical applications in OFET arrays. A novel method based on MSS named "indirect sublimation" was developed to cover entire substrate surface with SCs instead of patterning. The application of this method to produce OFETs based on "multi-SC" films was made into a new KAKENHI project (22K14293).

Free Research Field

有機トランジスタ

Academic Significance and Societal Importance of the Research Achievements

30cm2/Vsを超える極めて高いキャリア移動度を示し低電圧で駆動できる有機半導体材料「MT-ピレン」はディスプレイやIDタグへの応用などフレキシブルエレクトロニクスの進展に貢献することが期待できる。また、ピレンの二量体構造からMT-ピレンのレンガ型積層構造への構造変化のような、メチルチオ基の位置選択的導入による「結晶構造制御」は他のペリ縮合多環芳香族炭化水素分子に対しても有効である可能性が高く、新たな高移動度有機半導体材料開発に繋がる。さらに、本研究で開発された単結晶成長のための新手法「間接昇華」法は大面積化が容易で安価なことから近接昇華法や物理気相輸送法などに変わる手法となる可能性がある。