No abstract

Hydrogen energy is a zero-carbon replacement for fossil fuels. However, hydrogen is highly flammable and explosive hence timely sensitive leak detection is crucial. Existing optical sensing techniques rely on complex instruments, while electrical sensing techniques usually operate at high temperatures and biasing condition. In this paper an on-chip plasmonic–catalytic hydrogen sensing concept with a concentration detection limit down to 1 ppm is presented that is based on a metal–insulator–semiconductor (MIS) nanojunction operating at room temperature and zero bias. The sensing signal of the device was enhanced by three orders of magnitude at a one-order of magnitude higher response speed compared to alternative non-plasmonic devices. The excellent performance is attributed to the hydrogen induced interfacial dipole charge layer and the associated plasmonic hot electron modulated photoelectric response. Excellent agreements were achieved between experiment and theoretical calculations based on a quantum tunneling model. Such an on-chip combination of plasmonic optics, photoelectric detection and photocatalysis offers promising strategies for next-generation optical gas sensors that require high sensitivity, low time delay, low cost, high portability and flexibility.

No abstract

Harvesting energetic carriers from plasmonic resonance has been a hot topic in the field of photodetection in the last decade. By interfacing a plasmonic metal with a semiconductor, the photoelectric conversion mechanism, based on hot carrier emission, is capable of overcoming the band gap limitation imposed by the band−to−band transition of the semiconductor. To date, most of the existing studies focus on plasmonic structural engineering in a single metal–semiconductor (MS) junction system and their responsivities are still quite low in comparison to conventional semiconductor, material−based photodetection platforms. Herein, we propose a new architecture of metal−semiconductor–metal (MSM) junctions on a silicon platform to achieve efficient hot hole collection at infrared wavelengths with a photoconductance gain mechanism. The coplanar interdigitated MSM electrode’s configuration forms a back−to−back Schottky diode and acts simultaneously as the plasmonic absorber/emitter, relying on the hot−spots enriched on the random Au/Si nanoholes structure. The hot hole−mediated photoelectric response was extended far beyond the cut−off wavelength of the silicon. The proposed MSM device with an interdigitated electrode design yields a very high photoconductive gain, leading to a photocurrent responsivity up to several A/W, which is found to be at least 1000 times higher than that of the existing hot carrier based photodetection strategies.

The aim of this paper was to examine the sublethal toxic effects of nonylphenol ethoxylate (NP10EO), its primary degradation product nonylphenol (NP), and their mixture on Moina macrocopa. Chronic toxicity tests were carried out by using sublethal chemical concentrations. Results showed that all treatments reduced the survivorship, body length, and reproduction of M. macrocopa with NP being 10 %-20 % more toxic to M. macrocopa than NP10EO. Results also indicated that the toxic effects of NP10EO and NP mixture on M. macrocopa were more severe than that of any single chemical alone. At the highest concentration in this experiment, 0.337 mg L(-1) NP10EO plus 0.0154 mg L(-1) NP treatment caused the survivorship of M. macrocopa to zero, neonates number of reproductions to zero, 45.5 % reduction in the body length, and 88 % reduction in the total neonates number.