Two-dimensional MoS2-enabled flexible rectenna for Wi-Fi-band wireless energy harvesting

• Published in: Nature (London) 2019-02, Vol.566 (7744), p.368-372
• Main Authors: Zhang, Xu, Grajal, Jesús, Vazquez-Roy, Jose Luis, Radhakrishna, Ujwal, Wang, Xiaoxue, Chern, Winston, Zhou, Lin, Lin, Yuxuan, Shen, Pin-Chun, Ji, Xiang, Ling, Xi, Zubair, Ahmad, Zhang, Yuhao, Wang, Han, Dubey, Madan, Kong, Jing, Dresselhaus, Mildred, Palacios, Tomás
• Format: Article
• Language: English
• Subjects: 140/133; 140/146; 142/126; 639/4077/4072/4062; 639/925/927; Antennas; Bias; Diodes; Distributed sensor systems; Electromagnetic radiation; Electronic properties; Electronic systems; Electronics; Energy; Energy harvesting; Flexible components; Harvesters; Heterojunctions; Humanities and Social Sciences; Letter; Memory devices; Molybdenum disulfide; multidisciplinary; Object recognition; Radiation; Radio frequency; Rectennas; Science; Science (multidisciplinary); Semiconductor devices; Semiconductors; Sensors; Skin; Superhigh frequencies; Thin films; Transistors; Transport properties; Two dimensional materials
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/s41586-019-0892-1

The mechanical and electronic properties of two-dimensional materials make them promising for use in flexible electronics 1 – 3 . Their atomic thickness and large-scale synthesis capability could enable the development of ‘smart skin’ 1 , 3 – 5 , which could transform ordinary objects into an intelligent distributed sensor network 6 . However, although many important components of such a distributed electronic system have already been demonstrated (for example, transistors, sensors and memory devices based on two-dimensional materials 1 , 2 , 4 , 7 ), an efficient, flexible and always-on energy-harvesting solution, which is indispensable for self-powered systems, is still missing. Electromagnetic radiation from Wi-Fi systems operating at 2.4 and 5.9 gigahertz 8 is becoming increasingly ubiquitous and would be ideal to harvest for powering future distributed electronics. However, the high frequencies used for Wi-Fi communications have remained elusive to radiofrequency harvesters (that is, rectennas) made of flexible semiconductors owing to their limited transport properties 9 – 12 . Here we demonstrate an atomically thin and flexible rectenna based on a MoS 2 semiconducting–metallic-phase heterojunction with a cutoff frequency of 10 gigahertz, which represents an improvement in speed of roughly one order of magnitude compared with current state-of-the-art flexible rectifiers 9 – 12 . This flexible MoS 2 -based rectifier operates up to the X-band 8 (8 to 12 gigahertz) and covers most of the unlicensed industrial, scientific and medical radio band, including the Wi-Fi channels. By integrating the ultrafast MoS 2 rectifier with a flexible Wi-Fi-band antenna, we fabricate a fully flexible and integrated rectenna that achieves wireless energy harvesting of electromagnetic radiation in the Wi-Fi band with zero external bias (battery-free). Moreover, our MoS 2 rectifier acts as a flexible mixer, realizing frequency conversion beyond 10 gigahertz. This work provides a universal energy-harvesting building block that can be integrated with various flexible electronic systems. Integration of an ultrafast flexible rectifier made from a two-dimensional material with a flexible antenna achieves wireless energy harvesting of Wi-Fi radiation, which could power future flexible electronic systems.