Low-Dimensional In₂Se₃Compounds: From Material Preparations to Device Applications

Abstract

Nanostructured In2Se3 compounds have been widely used in electronics, optoelectronics, and thermoelectrics. Recently, the revelation of ferroelectricity in low-dimensional (low-D) In2Se3 has caused a new upsurge of scientific interest in nanostructured In2Se3 and advanced functional devices. The ferroelectric, thermoelectric, and optoelectronic properties of In2Se3 are highly correlated with the crystal structure. In this review, we summarize the crystal structures and electronic band structures of the widely interested members of the In2Se3 compound family. Recent achievements in the preparation of low-D In2Se3 with controlled phases are discussed in detail. General principles for obtaining pure-phased In2Se3 nanostructures are described. The excellent ferroelectric, optoelectronic, and thermoelectric properties having been demonstrated using nanostructured and heterostructured In2Se3 with different phases are also summarized. Progress and challenges on the applications of In2Se3 nanostructures in nonvolatile memories, photodetectors, gas sensors, strain sensors, and photovoltaics are discussed in detail. In the last part of this review, perspectives on the challenges and opportunities in the preparation and applications of In2Se3 materials are presented.

Self-Powered Photoelectrochemical Photodetectors Based on Electrochemically Exfoliated In2Se3 Nanosheets

“…Various 2D materials have been widely studied for photodetectors, − showing good photoresponse with high responsivity, fast response speed, and tunable response spectra. Among these 2D materials, 2D In 2 Se 3 has attracted much attention due to its suitable band gap, good photoresponse, and high stability. − The band gap of 2D In 2 Se 3 strongly depends on its thickness, ranging from 1.36 (multilayer) to 2.5 eV (monolayer) . The multilayer In 2 Se 3 phototransistors show an ultrahigh photoresponse of 9.8 × 10 4 A/W via the photogating effect .…”

Flexible Optical Synapses Based on In2Se3/MoS2 Heterojunctions for Artificial Vision Systems in the Near-Infrared Range

“…Flexible optical synaptic devices with NIR sensitivity, biomimetic plasticity, and flexibility have great application prospects in the fields of artificial visual systems, autopilot, the military system, free space communication, and robots, which have been attracting more and more attention in recent years. − Compared with traditional bulk materials, two-dimensional (2D) materials show great application prospects in the field of flexible NIR optical synapses because of their unique optical, electronic, and good mechanical flexibility. , The 2D materials include insulating hexagonal boron nitride (h-BN), graphene, transition-metal chalcogenides, , and main group metal chalcogenides. , However, due to the large band gap or no gap characteristics of most 2D materials, the realization of NIR light response is a dilemma at present. Moreover, synaptic plasticity and large-scale flexible wearable devices based on 2D materials under NIR illumination are difficult to realize, which hinders the development of flexible artificial visual systems .…”

“…7,21 The 2D materials include insulating hexagonal boron nitride (h-BN), 22 graphene, 23 transition-metal chalcogenides, 24,25 and main group metal chalcogenides. 26,27 However, due to the large band gap or no gap characteristics of most 2D materials, the realization of NIR light response is a dilemma at present. Moreover, synaptic plasticity and large-scale flexible wearable devices based on 2D materials under NIR illumination are difficult to realize, which hinders the development of flexible artificial visual systems.…”

“O-S” Charge Transfer Mechanism Guiding Design of a ZnIn2S4/SnSe2/In2Se3 Heterostructure Photocatalyst for Efficient Hydrogen Production

“…The I-III-VI chalcogenide semiconductor ZnIn 2 S 4 has been regarded as a brilliant H 2 evolution photocatalyst because of its suitable band gap (2.06–2.85 eV), negative conduction band potential, and robust chemical stability. − However, the photocatalytic H 2 evolution activity over pristine ZnIn 2 S 4 is always inefficient because of the sluggish photocarrier separation and transfer rate. , In 2 Se 3 is a typical representative of 2D transition-metal-chalcogenide, which has high carrier mobility, wide light absorbance scope, and low cost. , Especially, the conduction band potential of In 2 Se 3 is higher than that of ZnIn 2 S 4 , which is very conducive for photocatalytic H 2 evolution reaction. However, owing to the relatively narrow band gap, the recombination between photogenerated electrons and holes in pristine In 2 Se 3 is serious, thus leading to a poor H 2 production activity .…”