Pressure-sensitive electronic skin composed of a hierarchical structural array exhibits outstanding linear and high sensitivity in the pressure range exerted by gentle touch. By virtue of monolayer graphene acting as electrode material, this device can be operated with low voltage. Especially, its high transparency enables an accurate placement of the device on the target position when it is used for health monitoring.

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Next-generation flexible and transparent electronics demand newer materials with superior characteristics. Tin dichalcogenides, Sn(S,Se)2, are layered crystal materials that show promise for implementation in flexible electronics and optoelectronics. They have band gap energies that are dependent on their atomic layer number and selenium content. A variety of studies has focused in particular on tin disulfide (SnS2) channel transistors with conventional silicon substrates. However, the effort of interchanging the gate dielectric by utilizing high-quality hexagonal boron nitride (hBN) still remains. In this work, the hBN coupled SnS2 thin film transistors are demonstrated with bottom-gated device configuration. The electrical transport characteristics of the SnS2 channel transistor present a high current on/off ratio, reaching as high as 105 and a ten-fold enhancement in subthreshold swing compared to a high-κ dielectric covered device. We also demonstrate the spectral photoresponsivity from ultraviolet to infrared in a multi-layered SnS2 phototransistor. The device architecture is suitable to promote diverse studied on flexible and transparent thin film transistors for further applications.

We have studied defect states in an organic-inorganic hybrid solar cell containing Sb2S3 quantum dots (QDs) and TiO2 nanoparticles (NPs) by using deep level transient spectroscopy (DLTS). An Au electrode was deposited as a Schottky contact on the sample, where the Sb2S3 QDs were distributed on the surface of TiO2 NPs by chemical synthesis. The activation energy and capture-cross section of an interface state between the Sb2S3 QDs and the TiO2 NPs were found to be about 0.78 eV and 2.21 × 10−9 cm−2, respectively. Also, the densities of this interface trap under a measurement voltage of −1 V were approximately 2.5 × 1017 cm−3. Based on these results, the interface trap was positioned around Ec − 1.03 eV below the conduction band edge of Sb2S3 QD. Thus, the external quantum efficiency of the solar cell was affected because of its role as a recombination center for carriers generated from Sb2S3 QDs.

Molybdenum disulfide (MoS) film fabricated by a liquid exfoliation method has significant potential for various applications, because of its advantages of mass production and low-temperature processes. In this study, residue-free MoS thin films were formed during the liquid exfoliation process and their electrical properties were characterized with an interdigitated electrode. Then, the MoS film thickness could be controlled by centrifuge condition in the range of 20 ∼ 40 nm, and its carrier concentration and mobility were measured at about 7.36 × 10 cm and 4.67 cm V s, respectively. Detailed analysis on the films was done by atomic force microscopy, Raman spectroscopy, and high-resolution transmission electron microscopy measurements for verifying the film quality. For application of the photovoltaic device, a Au/MoS/silicon/In junction structure was fabricated, which then showed power conversion efficiency of 1.01% under illumination of 100 mW cm.