Two-Dimensional Mechano-thermoelectric Heterojunctions for Self-Powered Strain Sensors

Abstract

We here demonstrate the multifunctional properties of atomically thin heterojunctions that are enabled by their strong interfacial interactions and their application toward self-powered sensors with unprecedented performance. Bonding between tin diselenide and graphene produces thermoelectric and mechanoelectric properties beyond the ability of either component. A record-breaking ZT of 2.43 originated from the synergistic combination of graphene’s high carrier conductivity and SnSe2-mediated thermal conductivity lowering. Moreover, spatially varying interaction at the SnSe2/graphene interface produces stress localization that results in a novel 2D-crack-assisted strain sensing mechanism whose sensitivity (GF = 450) is superior to all other 2D materials. Finally, a graphene-assisted growth process permits the formation of high-quality heterojunctions directly on polymeric substrates for flexible and transparent sensors that achieve self-powered strain sensing from a small temperature gradient. Our work enhances the fundamental understanding of multifunctionality at the atomic scale and provides a route toward structural health monitoring through ubiquitous and smart devices.

Advances in flexible sensors for intelligent perception system enhanced by artificial intelligence

“…Apart from graphene, its derivatives, and MXene, other emerging 2D nanomaterials such as MoS 2 , 145,146 indium selenide (In 2 Se 3 ), 122,147 stannous sulfide (SnS), 100,148 tin diselenide, 149 vanadium nitride (VN), 123 and tin disulfide (SnS 2 )/SnS 150 have great potential in the field of flexible sensors as well, especially in tactile sensing. Hu et al 122 reported a class of 2D layered materials with an identical orientation of in-plane polarization whose piezoelectric coefficients (e 22 ) increased with layer number, thereby allowing the fabrication of flexible piezotronic devices with large piezoelectric responsivity and excellent mechanical durability (Figure 4F).…”

Strategies for Controlled Growth of Transition Metal Dichalcogenides by Chemical Vapor Deposition for Integrated Electronics

“…2D materials with a dangling-bond-free van der Waals structure break the limitation of the lattice-matching condition of heteroepitaxial growth and thus are promising candidates for vertical heterostructures. , The growth of TMD-based vertical heterostructures has been intensively developed in the past few years, including TMD/graphene, − TMD/h-BN, , TMD/perovskite, , TMD/iodide, , TMD/TMD, etc. Among them, TMD/TMD is worthy of great attention, as TMDs with a wide range of band gaps enable heterojunctions with distinct interfaces to be obtained, including metal–metal, semiconductor–semiconductor, and semiconductor–metal, adapting the requirements of diverse electronics and optoelectronics.…”

2D Materials for Wearable Energy Harvesting

“…reported on self‐powered strain sensors based on piezoelectric and thermoelectric energy harvesting. [ 1109 ] By combining the mechanoelectrical and thermoelectric properties of SnSe 2 and graphene heterostructures, the device achieved a record ZT value of 2.43 and functions as a strain sensor by measuring the variation of the output thermoelectric current. [ 1109 ] Wang et al.…”

“…[ 1109 ] By combining the mechanoelectrical and thermoelectric properties of SnSe 2 and graphene heterostructures, the device achieved a record ZT value of 2.43 and functions as a strain sensor by measuring the variation of the output thermoelectric current. [ 1109 ] Wang et al. also established the self‐powered pressure sensor capability of MXene‐enhanced PENG.…”