Wear-Resisting and Stable 4H-SiC/Cu-Based Tribovoltaic Nanogenerators for Self-Powered Sensing in a Harsh Environment

Abstract

Tribovoltaic nanogenerators (TVNGs) are an emerging class of devices for high-entropy energy conversion and mechanical sensing that benefit from their outstanding real-time direct current output characteristics. Here, a self-powered TVNG was fabricated using a small-area 4H-SiC semiconductor wafer and a large-area copper foil. Thus, the cost of materials remains low compared to devices employing large-scale semiconductors. The 4H-SiC/metal-TVNGs (SM-TVNGs) presented here are sensitive to vertical force and sliding velocity, making them appropriate for mechanical sensing. Notably, owing to the modulated bindingtons and surface states, these SM-TVNGs performed well in a harsh environment, namely, in high-temperature and high-humidity conditions. In addition, the SM-TVNGs exhibited an excellent wear-resisting property. On these bases, we designed a self-powered and real-time monitoring device able to estimate the number of staff present in various areas of a deep mining site, a high-temperature and high-humidity environment. This work not only discloses basic physics behind the tribovoltaic effect but also sheds light on possible applications of SM-TVNGs for wearresisting and stable mechanical sensors in harsh environments.

Triboelectric junction: a model for dynamic metal–semiconductor contacts

“…The tribovoltaic effect has been extensively studied using various materials, including first-generation semiconductors (such as Si 24 ), second-generation semiconductors (such as GaAs 50 ), third-generation semiconductors (such as GaN 14–16 and SiC 51 ), organic polymers (such as PEDOT:PSS 9,10 and polypyrrole 11 ), and 2D materials (such as graphene, 50 MoS 2 , 8,52 Ta 4 C 3 52 and Ti 2 C 3 T x 53 ), etc. Note that the derivation of the theoretical model is specially based on conventional inorganic semiconductor materials.…”

Reversal in Output Current Direction of 4H‐SiC/Cu Tribovoltaic Nanogenerator as Controlled by Relative Humidity

“…[ 24 ] Among these parameters, the effect of relative humidity varies drastically as a function of the nature of the interfaces used to form the TVNG. [ 25 ] However, these papers generally stopped their investigations at the observation and lacked discussions surrounding the mechanism behind the discrepancy in RH dependence that exists between different devices.…”

“…[ 27,28 ] Moreover, in the case of TVNGs, it demonstrated the ability to deliver excellent output performances in harsh environments, which motivated our choice for this study of TVNGs in various RH conditions. [ 25 ] Therefore, we built a TVNG based on a Schottky structure fabricated with a nitrogen‐doped 4H‐SiC single crystal and a metal Cu foil (SM‐TVNG) and studied its behavior under varying RH and underwater. We observed an abnormal output dependence on RH from our SM‐TVNG.…”

MXene Lubricated Tribovoltaic Nanogenerator with High Current Output and Long Lifetime

“…Various methods have been proposed to solve this problem, such as optimizing friction pairs and interface lubrication. Recently, 4H-SiC and Cu were used as a friction pair to fabricate TVNG device, which has improved output current at high humidity and can maintain good stability after 400 cycles [ 33 ]. Instead of Cu with Mxene powder and Si as a friction pair, the current density and lifetime of TVNG increased to 97.8 mA m −2 and 1800 cycles [ 34 ].…”