scholarly journals Visible Light-Driven p-Type Semiconductor Gas Sensors Based on CaFe2O4 Nanoparticles

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 850
Author(s):  
Qomaruddin Qomaruddin ◽  
Olga Casals ◽  
Andris Šutka ◽  
Tony Granz ◽  
Andreas Waag ◽  
...  
Keyword(s):  
Visible Light ◽  
Gas Sensors ◽  
Light Emitting Diode ◽  
Ethanol Exposure ◽  
Desorption Process ◽  
Light Emitting ◽  
Type Semiconductor ◽  
Visible Light Driven ◽  
Calcium Iron ◽  
P Type

In this work, we present conductometric gas sensors based on p-type calcium iron oxide (CaFe2O4) nanoparticles. CaFe2O4 is a metal oxide (MOx) with a bandgap around 1.9 eV making it a suitable candidate for visible light-activated gas sensors. Our gas sensors were tested under a reducing gas (i.e., ethanol) by illuminating them with different light-emitting diode (LED) wavelengths (i.e., 465–640 nm). Regardless of their inferior response compared to the thermally activated counterparts, the developed sensors have shown their ability to detect ethanol down to 100 ppm in a reversible way and solely with the energy provided by an LED. The highest response was reached using a blue LED (465 nm) activation. Despite some responses found even in dark conditions, it was demonstrated that upon illumination the recovery after the ethanol exposure was improved, showing that the energy provided by the LEDs is sufficient to activate the desorption process between the ethanol and the CaFe2O4 surface.

scholarly journals Visible-Light-Driven Photocatalytic Activity of Magnetic BiOBr/SrFe12O19 Nanosheets

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 735 ◽  
Author(s):  
Taiping Xie ◽  
Jiao Hu ◽  
Jun Yang ◽  
Chenglun Liu ◽  
Longjun Xu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Electron Microscope ◽  
Visible Light ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Active Species ◽  
Composite Catalyst ◽  
Light Emitting ◽  
Transmission Electron ◽  
Visible Light Driven

Magnetic BiOBr/SrFe12O19 nanosheets were successfully synthesized using the hydrothermal method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and UV-visible diffused reflectance spectra (UV-DRS), and the magnetic properties were tested using a vibration sample magnetometer (VSM). The as-produced composite with an irregular flaky-shaped aggregate possesses a good anti-demagnetization ability (Hc = 861.04 G) and a high photocatalytic efficiency. Under visible light (λ > 420 nm) and UV light-emitting diode (LED) irradiation, the photodegradation rates of Rhodamine B (RhB) using BiOBr/SrFe12O19 (5 wt %) (BOB/SFO-5) after 30 min of reaction were 97% and 98%, respectively, which were higher than that using BiOBr (87%). The degradation rate of RhB using the recovered BiOBr/5 wt % SrFe12O19 (marked as BOB/SFO-5) was still more than 85% in the fifth cycle, indicating the high stability of the composite catalyst. Meanwhile, after five cycles, the magnetic properties were still as stable as before. The radical-capture experiments proved that superoxide radicals and holes were main active species in the photocatalytic degradation of RhB.

A p-type Ti(iv)-based metal–organic framework with visible-light photo-response

2014 ◽  
Vol 50 (29) ◽  
pp. 3786-3788 ◽  
Author(s):  
Junkuo Gao ◽  
Jianwei Miao ◽  
Pei-Zhou Li ◽  
Wen Yuan Teng ◽  
Ling Yang ◽  
...  
Keyword(s):  
Visible Light ◽  
Metal Organic Framework ◽  
Porous Metal ◽  
Type Semiconductor ◽  
Visible Light Driven ◽  
Metal Organic ◽  
Photo Response ◽  
P Type ◽  
Photoelectrochemical Studies ◽  
Organic Framework

Photoelectrochemical studies on a new Ti(iv)-based porous metal–organic framework (NTU-9, bandgap 1.72 eV) indicated that NTU-9 is a p-type semiconductor with visible-light-driven photoactivity.

NP Heterojunction Porous Silicon Light-Emitting Diode

1991 ◽  
Vol 256 ◽  
Author(s):  
Nader M. Kalkhoran ◽  
F. Namavar ◽  
H. P. Maruska
Keyword(s):  
Porous Silicon ◽  
Indium Tin Oxide ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Wide Bandgap ◽  
Heterojunction Diode ◽  
Light Emitting ◽  
Type Semiconductor ◽  
P Type ◽  
Bias Condition

ABSTRACTWe report the first demonstration of visible light emission from an all solid-state n-p heterojunction diode based on porous silicon. The p-type silicon was electrochemically etched in a hydrofluoric acid solution to form a porous silicon region; the n-p heterojunction diode was fabricated by depositing a wide bandgap n-type semiconductor, indium-tin-oxide (ITO), onto the surface of the porous silicon. With positive bias applied, electroluminescence was observed with a relatively narrow peak at about 580 nm. The device showed strong rectifying properties and no light emission was observed under reverse bias condition. Photoluminescence in the red, orange, yellow, and green was also observed in separate sample preparations.

scholarly journals Hybrid photocathode consisting of a CuGaO2 p-type semiconductor and a Ru(ii)–Re(i) supramolecular photocatalyst: non-biased visible-light-driven CO2 reduction with water oxidation

2017 ◽  
Vol 8 (6) ◽  
pp. 4242-4249 ◽  
Author(s):  
Hiromu Kumagai ◽  
Go Sahara ◽  
Kazuhiko Maeda ◽  
Masanobu Higashi ◽  
Ryu Abe ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Oxidation ◽  
Co2 Reduction ◽  
Type Semiconductor ◽  
Visible Light Driven ◽  
P Type

A new Ru(ii)–Re(i)/CuGaO2 hybrid photocathode was developed and combined with a CoOx/TaON photoanode to drive non-biased visible-light-driven CO2 reduction with water oxidation.

Ultraviolet light-emitting diode-assisted highly sensitive room temperature NO2 gas sensor for low-temperature solution-processed ZnO/TiO2 nanorods decorated with plasmonic Au nanoparticles

Nanoscale ◽  
2021 ◽  
Author(s):  
Soon-Hwan Kwon ◽  
Tae-Hyeon Kim ◽  
Sang-Min Kim ◽  
Semi Oh ◽  
Kyoung-Kook Kim
Keyword(s):  
Gas Sensors ◽  
High Performance ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
No2 Gas Sensor ◽  
Highly Sensitive ◽  
Temperature Solution ◽  
Semiconducting Metal Oxides

Nanostructured semiconducting metal oxides such as SnO2, ZnO, TiO2, and CuO have been widely used to fabricate high performance gas sensors. To improve the sensitivity and stability of gas sensors,...

scholarly journals Effects of Temperature and Host Concentration on the Supramolecular Enantiodifferentiating [4 + 4] Photodimerization of 2-Anthracenecarboxylate through Triplet-Triplet Annihilation Catalyzed by Pt-Modified Cyclodextrins

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1502 ◽  
Author(s):  
Ming Rao ◽  
Wanhua Wu ◽  
Cheng Yang
Keyword(s):  
Light Emitting Diode ◽  
Temperature Dependency ◽  
Light Emitting ◽  
Modified Cyclodextrins ◽  
Direct Irradiation ◽  
Visible Light Driven ◽  
Significant Temperature ◽  
Effects Of Temperature ◽  
532 Nm ◽  
Triplet Triplet Annihilation

Visible-light-driven photocatalytic supramolecular enantiodifferentiating dimerization of 2-anthracenecarboxylic acid (AC) through triplet-triplet annihilation (TTA), mediated by the Schiff base Pt(II) complex (Pt-1, Pt-2, and Pt-3) was studied. The host concentration and the temperature effects on the stereoselectivity were comprehensively investigated. Increasing the concentration of sensitizers/hosts significantly enhanced the conversion of the photoreaction but led to reduced enantioselectivities of the chiral photodimers 2 and 3 when the photoreaction was triggered by a 532 nm laser, which was in contrast with the results obtained by direct irradiation of AC with a 365 nm light-emitting diode (LED) lamp, due to the aggregation of the sensitizer/host in water. The cyclization of AC through triplet-triplet annihilation displayed significant temperature dependency when Pt-3 was employed as the sensitizer/host. Increasing the temperature from 0 °C to 30 °C with 5% equiv. of Pt-3 led to a great increase of the ee of 2 from 2.1% to 31.6%. However, hardly any temperature dependency was observed when the photodimerization was mediated by other sensitizers and/or hosts, or the photoreaction was triggered directly with a 365 nm LED lamp.

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