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Multilayer InSe is a promising material for high-performance optoelectronic applications because of its small direct band gap and good light absorption. However, as a photoconductive photodetector,...

Although single ultra-high-performance indicators have been achieved based on two-dimensional (2D) semiconductors, the comprehensive performances of the photodetectors of them are not so desirable. The response speed and responsivity are two key figures of merit for photodetectors, while these two parameters are always mutually suppressive and can not be synchronously satisfied. Here, we proposed a feasible strategy that can simultaneously improve the responsivity and response speed of In2Se3-based photodetectors by applying the mechanical strain and producing the piezoresistive effect, which can synergistically modulate the band structure and boost the overall photodetecting performances. Through studying the optoelectronic properties of In2Se3 photodetector under strain modulations, we found that the responsivity under 0.65% tensile strain is improved by almost 68.6% on average, while responsivity under 0.65% compressive strain is lowered by about 57.3% in the wavelength range of 200-1000 nm. More importantly, the response speed of the In2Se3-based photodetector under two different mechanical strains rises distinctly (from 244 to 214 and 180 μs, accordingly). The strain-engineering can accommodate the band structure and enhance the electric and optical properties of the semiconducting crystals, ultimately realizing high-performance photodetectors. The strategy proposed in this work for improving the performance of photodetectors provides a promising route to practical applications in next-generation optoelectronic devices.

Here, we report electronic and optoelectronic performance of multilayer In2Se3 are effectively regulated by phase engineering. The electron mobility is increased to 22.8 cm2 V-1 s-1 for β-In2Se3 FETs, which is 18 times higher than 1.26 cm2 V-1 s-1 of α-In2Se3 FETs. The enhanced electronic performance is attributed to larger carrier sheet density and lower contact resistance. Multilayer β-In2Se3 photodetector exhibits an ultrahigh responsivity of 8.8 × 104 A/W under 800 nm illumination, which is 574 times larger than 154.4 A/W of α-In2Se3 photodetector. Our results demonstrate phase-engineering is a valid way to tune and further optimize electronic and optoelectronic performance of multilayer In2Se3 nanodevices.

The electrocatalytic hydrogen evolution reaction (HER) has attracted increasing attention in the field of hydrogen-based economy, whereat developing cheap and efficient catalysts to reduce the use of Pt-based catalysts is highly required. Tin disulfide (SnS2) as a new rising star has exhibited intriguing properties in energy storage and conversion applications, while showing slow progress in HER due to the inherent poor activity. Herein, we demonstrate the successful structural engineering and simultaneous integration of trace amount Pt in SnS2 nanosheets via a facile and effective in situ cycling voltammetry activation process, leading to the efficiently synergistic HER. Defect-rich SnS2 nanosheets decorated with a trace amount (0.37 wt %) of Pt exhibit greatly enhanced HER activity due to the synergy between them, revealing low onset potential of 32 mV and overpotential of 117 mV at 10 mA/cm2, small Tafel slope of 69 mV/dec, and large exchange current density of 394.46 μA/cm2. Present work provides an i...