Graphene-Quantum-Dots-Induced Centimeter-Sized Growth of Monolayer Organic Crystals for High-Performance Transistors
Jinwen Wang1, Xiaofeng Wu1, Jing Pan1, Tanglue Feng2, Di Wu3, Xiujuan Zhang1, Bai Yang2, Xiaohong Zhang1, and Jiansheng Jie1,*
1Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, P. R. China.
2State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun, Jilin 130012, P. R. China.
3School of Physics and Microelectronics, Key Laboratory of Material Physics, Ministry of Education, Zhengzhou University, Zhengzhou, Henan 450052, P. R. China.
Monolayer organic crystals have attracted considerable attention due to their extraordinary optoelectronic properties. Solution self-assembly on the surface of water is an effective approach to fabricate monolayer organic crystals. However, due to the difficulties in controlling the spreading of organic solution on the water surface and the weak intermolecular interaction between the organic molecules, large-area growth of monolayer organic crystals remains a great challenge. Here, a graphene quantum dots (GQDs)-induced self-assembly method for centimeter-sized growth of monolayer organic crystals on a GQDs solution surface is reported. The spreading area of the organic solution can be readily controlled by tuning the pH value of the GQDs solution. Meanwhile, the π–π stacking interaction between the GQDs and the organic molecules can effectively reduce the nucleation energy of the organic molecules and afford a cohesive force to bond the crystals, enabling large-area growth of monolayer organic crystals. Using 2,7-didecyl benzothie-nobenzothiopene (C10-BTBT) as an examples, centimeter-sized monolayer C10-BTBT crystal with uniform molecular packing and crystal orientation is attained. Organic ﬁeld-effect transistors based on the monolayer C10-BTBT crystals exhibit a high mobility up to 2.6 cm2 V-1 s-1, representing the highest mobility value for solution-assembled monolayer organic crystals. This work provides a feasible route for large-scale fabrication of monolayer organic crystals toward high-performance organic devices.