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School of Physics and Astronomy

Xiaoming Zhao


Research Student

Room Number: G.O. Jones Building Room 211


1st Supervisor: Dr John Dennis
2nd Supervisor: Dr Isaac Abrahams

Project Title: Fullerene Single-crystalline Nanostructures for Organic Electronics.
Project Description:

Single crystals of organic semiconductors, being free of grain boundaries and molecular disorders, have been shown to exhibit high performance such as the superior charge carrier mobility and long exciton diffusion. On this point, organic single crystals would be ideal candidate for high performance electronic devices and for intrinsic property studies. Fullerene materials are among the most widely-used materials for organic electronics. For instance, organic field-effect transistors (OFETs) based on C60 single crystals exhibit electron mobilities exceeding 10 cm2 V1 s1, one of the highest among n-channel OFETs. For organic photovoltaics (OPVs), the fullerene derivative of [6,6]-phenyl C61 butyric acid methyl ester ([60]PCBM) is the most widely used electron acceptor and has important functions in OPVs with high power conversion efficiency. However, most of these organic electronic devices are yet based on fullerene in amorphous phase, which limits the enhancement of the device performance. Grain boundaries and molecular disorder in amorphous thin films scatter the charge carriers by the effect of coulomb scattering, which results in the reduction of charge carrier mobility. Thus, this challenge remains a major bottleneck in the advancement of device performance.

In my project, the application of fullerene single crystals in organic electronics are discussed. It not only discusses the controllable crystal growth of fullerene single crystals, but also describes the performance enhancement of OFETs, OPVs, organic photodetectors via employing fullerene single crystals. In addition, the intrinsic charge transport properties of the nitrogen atom encapsulated fullerene (N@C60) single crystals, [60]PCBM single crystals and fullerene single-crystalline p-n heterojunctions are comprehensively studied.



Antisolvent-Assisted Controllable Growth of Fullerene Single Crystal Microwires for Organic Field Effect Transistors and Photodetectors. Xiaoming Zhao, Tianjun Liu, Yuzhou Cui, Xueyan Hou, Zilu Liu, Xingyi Dai, Jie Kong, Wenda Shi, T. John S. Dennis. Nanoscale 2018, 10 (17), 8170-8179.

Understanding Charge Transport in Endohedral Fullerene Single-Crystal Field-Effect Transistors. Xiaoming Zhao, Tianjun Liu, Wenda Shi, Xueyan Hou, Zilu Liu, T. John S. DennisThe Journal of Physical Chemistry C 2018, 122 (16), 8822-8828.

Organic Single-Crystalline Donor-Acceptor Heterojunctions with Ambipolar Band-Like Charge Transport for Photovoltaics. Xiaoming Zhao, Tianjun Liu, Yuteng Zhang, Shirong Wang, Xianggao Li, Yin Xiao, Xueyan Hou, Zilu Liu, Wenda Shi, T. John S. Dennis. Advanced Materials Interfaces 2018, In Press

[60]PCBM Single Crystals: Remarkably Enhanced Band-like Charge Transport, Broadband UV-Visible-NIR Photo-responsivity and Improved Long-term Air-stability. Xiaoming Zhao, Tianjun Liu, Wenda Shi, Xueyan Hou, Zilu Liu, T. John S. Dennis. Journal of Materials Chemistry C 2018, In Press

Solution-Processed Organic Single-Crystalline Donor-Acceptor Heterojunction Arrays for High-Performance Ambipolar Field-Effect Transistors and Photoelectronic Devices. Xiaoming Zhao, Tianjun Liu, Xueyan Hou, Zilu Liu, Wenda Shi, T. John S. Dennis. Nature Communications, Under Review.

Isomer-Pure Bis-PCBM-Assisted Crystal Engineering of Perovskite Solar Cells Showing Excellent Efficiency and Stability. Fei Zhang, Wenda Shi, Jingshan Luo, Norman Pellet, Chenyi Yi, Xiong Li, Xiaoming Zhao, T John S Dennis, Xianggao Li, Shirong Wang, Yin Xiao, Shaik Mohammed Zakeeruddin, Dongqin Bi, Michael Grätzel. Advanced Materials. 2017, 29 (17), 1606806.

Purification and Electronic Characterisation of 18 Isomers of the OPV Acceptor Material Bis-[60]PCBM. Wenda Shi, Xueyan Hou, Tianjun Liu, Xiaoming Zhao, A. Sieval, Jan C. Hummelen, T. John S. Dennis. Chemical Communications 2017, 53 (5), 975–978.