Visible light activated room temperature gas sensors based on nanocrystalline ZnO sensitized with CdSe quantum dots

Gold Decoration and Photoresistive Response to Nitrogen Dioxide of WS2 Nanotubes

“…Both the processes result in a decrease of the sensor resistance under illumination (Figure a, inset). In principle, this mechanism is somehow similar to the chemisorption/ photodesorption of oxidizing gases occurring on the surface of metal‐oxide sensors, however the amount of electrons transferred per one NO 2 or O 2 molecule is far below 1 e − , typical for chemisorption processes.…”

“…The R dark / R light ratio changes with increasing NO 2 concentration non‐monotonously (Figure b), so the photoresponse cannot be easily used as a reliable analytical signal for the studied materials. Instead, two other values were calculated, as proposed elsewhere:…”

“…Nowadays, resistive gas sensors have received great attention due to their effective applications in inexpensive devices for ecological monitoring, exhaust gases control in vehicles and industry, fire safety, medical diagnostics, as well as in future applications like artificial olfaction and smart sensors for the Internet of Things . Among others, nitrogen dioxide gas sensors are of great importance because NO 2 is known to be a highly hazardous substance still playing a crucial role in some industrial processes and medical sterilization techniques .…”

“…Nowadays, resistive gas sensors have received great attention due to their effective applications in inexpensive devices for ecological monitoring, exhaust gases control in vehicles and industry,f ire safety,m edical diagnostics, as well as in future applicationsl ike artificial olfaction and smart sensors fort he Internet of Things. [1][2][3] Amongo thers, nitrogend ioxide gas sensors are of great importance because NO 2 is known to be a highly hazardous substance still playingacrucial role in some industrialp rocesses and medical sterilization techniques. [4,5] While metal-oxide n-type semiconductors are currently the most popular materials for commercial gas sensors; [6,7] the other effective gas-sensitiven anomaterials are still intensively developed to achieve high sensitivity,f ast response, low detection limits, energy efficiency,and other required parameters.…”

Indirect detection of alcoholic strength in spirits by fluorescence method using the polyethyleneimine capped ZnO QDs

“…ZnO QDs have high quantum yield, quantum size effects, broad absorption and narrow emission spectrum as other semiconductor QDs. On the other hand, ZnO QDs are environment-friendly, nontoxic, less expensive, and biocompatible to the biological system compared to traditional semiconductor QDs (such as CdS, CdTe, and CdSe) [29][30][31][32] such as solar cells, live cell imaging, drug delivery, UV photodetector, gas sensors, and organic detection, where their prominent optical and electrical properties become one of the focus issues [33][34][35][36][37][38][39][40][41]. Therefore, the ZnO QDs with excellent fluorescence properties can be used as a fluorescent probe to determine biological and chemical substances and biological imaging.…”