Precise Patterning of Organic Single Crystals via Capillary‐Assisted Alternating‐Electric Field

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 13; no. 25
• Main Authors: Zhang, Yedong, Jie, Jiansheng, Sun, Yuning, Jeon, Seok‐Gy, Zhang, Xiujuan, Dai, Gaole, Lee, Cheol Jin, Zhang, Xiaohong
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01-07-2017
• Subjects: alternating‐electric field; Assembling; Assembly; capillary force; Electric power distribution; Electronic devices; Nanocrystals; Nanostructure; Nanotechnology; Optoelectronic devices; Organic crystals; organic single crystals; Photolithography; Photometers; precise patterning; Reproducibility; Single crystals; Substrates; Ultraviolet; UV photodetectors; capillary force; alternating-electric field; precise patterning; UV photodetectors; organic single crystals
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201604261

Owing to the extraordinary properties, organic micro/nanocrystals are important building blocks for future low‐cost and high‐performance organic electronic devices. However, integrated device application of the organic micro/nanocrystals is hampered by the difficulty in high‐throughput, high‐precision patterning of the micro/nanocrystals. In this study, the authors demonstrate, for the first time, a facile capillary‐assisted alternating‐electric field method for the large‐scale assembling and patterning of both 0D and 1D organic crystals. These crystals can be precisely patterned at the photolithography defined holes/channels at the substrate with the yield up to 95% in 1 mm2. The mechanism of assembly kinetics is systematically studied by the electric field distribution simulation and experimental investigations. By using the strategy, various organic micro/nanocrystal patterns are obtained by simply altering the geometries of the photoresist patterns on substrates. Moreover, ultraviolet photodetectors based on the patterned Alq3 micro/nanocrystals exhibit visible–blind photoresponse with high sensitivity as well as excellent stability and reproducibility. This work paves the way toward high‐integration, high‐performance organic electronic, and optoelectronic devices from the organic micro/nanocrystals.
A capillary‐assisted alternating‐electric field method is developed for precise assembling and patterning of organic micro/nanocrystals on a large scale. Both Alq3 microplates and nanorods are patterned with the assembly yield up to 95% in 1 mm2. High‐sensitivity and visible–blind ultraviolet photodetectors are further constructed based on the patterned organic micro/nanocrystals.