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

• Published in: Nature (London) Vol. 566; no. 7744; pp. 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: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 21-02-2019; Nature Publishing Group
• 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.