Yunqi Liu1

1, Institute of Chemistry, Chinese Academy of Sciences, Beijing, , China

Great interests have been aroused in flexible functional electronics and photoelectraonics, such as artificial skin, non-volatile memories, photosensors and health monitoring systems. Packed up through van der Waals interactions, organic/polymeric materials have advantages of intrinsic mechanical flexibility. During the past several years, impressive progresses have been made in organic field-effect transistors (OFETs), particularly in conjugated polymer-based FETs. A few high-performance polymers-based FETs have been developed with a remarkable mobility of more than 10 cm2 V−1 s−1, which provides a promising opportunity for applications in flexible displays and wearable devices.
In this presentation, we report an organic photosensor by three-component integration:[1] an organic light-dependant resistor (OLDR), an organic resistor (OR) as a load resistor, and an OFET as readout element. The photosensor is transconductance type instead of conductance, thus giving a higher photo to dark on/off ratio. In adittion, as a mimicry and spectral extension of human visual system, we present an integrated, retina-like optoelectronic device[2] for filter-free near-infrared (NIR) imaging and memory purposes. The device transforms NIR signals into grey scale nonvolatile resistance states, enabling a NIR-to-memory capability. We also demonstrate color differentiation between NIR and visible incidents with preferred NIR selectivity. Due to circuit design, our retinal system accomodates a bi-modal operation with respect to incident wavelengths. It functions as nonvolatile memory under NIR (850 nm) with a dynamic range of 62 dB and 86 dB photoswitch under green light (550 nm). On the other hand, we report the design and synthesis of some copolymers with D−A structures exhibiting p-tpye, n-type and ambipolar behavior as well.[3-6]

1. Hanlin Wang, Hongtao Liu, Qiang Zhao, Cheng Cheng, Wenping Hu, and Yunqi Liu, Adv. Mater., 2016, 28(4), 624-630.
2. Hanlin Wang, Hongtao Liu, Qiang Zhao, Zhenjie Ni, Ye Zou, Jie Yang, Lifeng Wang, Yanqiu Sun, Yunlong Guo, Wenping Hu, and Yunqi Liu, Adv. Mater., 2017, 29(32), 1701722.
3. Zhiyuan Zhao, Zhihong Yin, Huajie Chen, Liping Zheng, Chunguang Zhu, Long Zhang, Songting Tan, Hanlin Wang, Yunlong Guo, Qingxin Tang, and Yunqi Liu, Adv. Mater., 2017, 29(4), 1602410.
4. Jie Yang, Hanlin Wang, Jinyang Chen, Jianyao Huang, Yingying Jiang, Jianqi Zhang, Longxian Shi, Yunlong Sun, Zhixiang Wei, Gui Yu, Yunlong Guo, Shuai Wang, and Yunqi Liu, Adv. Mater, 2017, 29(22), 1606162.
5. Jie Yang, Zhiyuan Zhao, Hua Geng, Changli Cheng, Jinyang Chen, Yunlong Sun, Longxian Shi, Yuanping Yi, Zhigang Shuai, Yunlong Guo, Shuai Wang, and Yunqi Liu, Adv. Mater., 2017, 29(36), 1702115.
6. Chunguang Zhu, Zhiyuan Zhao, Huajie Chen, Liping Zheng, Xiaolin Li, Jinyang Chen, Yanming Sun, Feng Liu, Yunlong Guo, and Yunqi Liu, J. Am. Chem. Soc., 2017, 139 (49), 17735–17738.