Insights into the Interfacial Contact and Charge Transport of Gas-Sensing Liquid Metal Marbles

Abstract

Understanding the interfacial contacts between liquid metals and substrate materials is becoming increasingly important for the fast-rising liquid metal-enabled technologies. However, for such technologies, probing the contact behavior and interfacial charge transport has remained challenging due to the deformable nature of liquid metals and the presence of the surface oxide layer. Here, we encapsulate eutectic gallium indium (EGaIn) micro-/nanodroplets with tungsten trioxide (WO3) nanoparticles to form a WO3/EGaIn liquid metal marble network, in which the interfacial contact of the intrinsically semiconducting WO3 governs the charge transport. We investigate the interfacial structures and charge transport characteristics under different contact conditions and various gaseous environments. The results suggest that establishing a WO3/EGaIn heterostructure leads to near-ohmic contact behaviors and also the emergence of localized surface plasmon resonance. Density functional theory calculations of the WO3/EGaIn interface support the experiments by revealing atomistic attractions between EGaIn alloy and the O atoms from WO3, resulting in a Fermi level shift. We also show that the efficient interfacial charge transport of the liquid metal marble network results in an enhanced gas-sensing response. This work paves the way for the possibility of studying other liquid metal/semiconductor contacts for applications in soft electronics and optics.

Mechanistic Observation of Interactions between Macrophages and Inorganic Particles with Different Densities

“…Preparation of Particles using a Liquid Metal-Based Process: Ga, In, Bi, and Sn particles were all synthesized by ultrasonication using a probe sonicator (Sonics VCX 750, Sonics & Materials, Inc.). [37,39,40] Briefly, a bulk metal was heated to melt and added with a medium (10 mL) in a glass vial with/without a bath that was placed on a hot plate. A probe (diameter: 6 mm) was immersed into the metal-medium mixture, which was then sonicated with a burst mode (on/off) for a certain period.…”

Smart Eutectic Gallium–Indium: From Properties to Applications

“…[62][63][64] Chi et al constructed tungsten trioxide (WO 3) /EGaIn liquid metal marbles by wrapping WO 3 nanoparticles on EGaIn micro-nano droplets, which can be used as gas sensors by enhancing the response to gas sensing through efficient interfacial transport. [65] Lu et al combined EGaIn nanoparticles with drug molecules and ligands, and the prepared nanomedicine could be used for tumor treatment. [66] Adv.…”

Size-Controlled Low-Melting-Point-Alloy Particle-Incorporated Transient Liquid-Phase Epoxy Composite Conductive Adhesive with High Performances

“…However, further reduction of the LMPA size using the conventional methods becomes difficult and costly, because the LMPA would become nonuniform with more impurities included as its size scales down . Fortunately, an emerging technique, namely, ultrasonic cavitation, can be used to synthesize spherical particles of LMPA with precisely controlled composition and tunable size (0.3–50 μm). , Friedman et al successfully used the ultrasonic cavitation method for preparing various pure metals (Ga, In, Sn, Bi, Pb, Zn, and Hg) and eutectic alloys (Au-Ge, Au-Si), by dispersing the molten metal into microspheres with the aid of a quasiemulsion system. However, to the best of the authors’ knowledge, LMPA particles synthesized using the ultrasonic cavitation method have not yet been incorporated in TLP-ECAs composite materials.…”