Graphene is an ideal material for highperformance photodetectors because of its superior electronic and optical properties. However, graphene's weak optical absorption limits the photoresponsivity of conventional photodetectors based on planar (two-dimensional or 2D) back-gated graphene field-effect transistors (GFETs). Here, we report a self-rolled-up method to turn 2D buried-gate GFETs into three-dimensional (3D) tubular GFETs. Because the optical field inside the tubular resonant microcavity is enhanced and the light−graphene interaction area is increased, the photoresponsivity of the resulting 3D GFETs is significantly improved. The 3D GFET photodetectors demonstrated room-temperature photodetection at ultraviolet, visible, mid-infrared, and terahertz (THz) regions, with both ultraviolet and visible photoresponsivities of more than 1 A W −1 and photoresponsivity of 0.232 A W −1 at 3.11 THz. The electrical bandwidth of these devices exceeds 1 MHz. This combination of high photoresponsivity, a broad spectral range, and high speed will lead to new opportunities for 3D graphene optoelectronic devices and systems.
The inhibition kinetics of dichlorvos on carboxylesterase and acetylcholinesterase (AChE) activity extracted from Liposcelis bostrychophila and L. entomophila (Psocoptera: Liposcelididae) were compared. The results showed that L. entomophila had significantly greater specific activity of carboxylesterase than L. bostrychophila (0.045 versus 0.012 µmoles /mg /min). Moreover, the carboxylexterase of L. entomophila showed higher affinity (i.e. lower Km value) to the substrate 1-naphthyl acetate than L. bostrychophila (0.29 versus 0.67 mM). The specific activity and affinity of AChE of the two species were not significantly different. The carboxylesterase of L. bostrychophila was more sensitive to the insecticide dichlorvos than that of L. entomophila. The I 50 s values of dichlorvos to carboxylesterase for L. bostrychophila and L. entomophila were 1.43 and 3.28 µM, respectively, and to AChE were 324 and 612 nM, respectively. Inhibition kinetics revealed that AChE from L. bostrychophila was 5.8-fold more sensitive to inhibition than AChE from L. entomophila.
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