Showing papers by "Xihua Wang published in 2018"
TL;DR: In this article, a filter-free narrowband photodetectors using PbS and HgSe CQD materials is proposed to improve the spectral response of a photodiode device.
Abstract: Tuning the electronic bandgap of quantum dots via the quantum size-effect enables the tailored spectral response of quantum dot photodetectors, light emitting diodes, and solar cells. Chemically synthesized colloidal quantum dot (CQD) provides an option to produce such quantum material in an inexpensive way. Here, we propose an approach to fabricate filter-free narrowband photodetectors in near-infrared and mid-infrared regions using PbS and HgSe CQD materials, respectively. The spectrally selective bandpass response is implemented by taking advantage of the carrier collection narrowing effect using a photodiode device architecture. Narrower bandpass response in near-infrared region is further achieved employing blended PbS CQDs with different sizes. The external quantum efficiency spectra of these CQD detectors are comprehensively studied using numerical calculation.
15 citations
TL;DR: It is demonstrated that the light redistribution by the surface nanolens in TIR enables a range of novel applications in selectively local visualization of specimens in fluorescence imaging, optical trapping of colloids from an external flow, and selective materials deposition from photoreactions.
Abstract: Microscopic lenses are paramount in solar energy harvesting, optical devices, and imaging technologies. This work reports an extraordinary focusing effect exhibited by a surface nanolens (i.e., with at least one dimension of subwavelength) that is situated in an evanescent field from the total internal reflection (TIR) of light illuminated to the supporting substrate above the critical angle. Our measurements show that the position, shape, and size of the surface area with enhanced light intensity are determined by the geometry of the nanolens and the incident angle, in good agreement with simulation results. This strong focusing effect of the surface nanolens is shown to significantly promote the plasmonic effect of deposited gold nanoparticles on the lens surface inlight conversion and to vaporize surrounding water to microbubbles by using low laser power. This work further demonstrates that the light redistribution by the surface nanolens in TIR enables a range of novel applications in selectively loca...
12 citations
TL;DR: This work has demonstrated that via evaporation of hydrocarbons inside the periodic structure of inverse opal photonic crystals and observation of their reflection spectra, an inverseOpal film could be used as a fast-response optofluidic sensor to accurately differentiate pure hydrocarbon liquids and relative concentrations of their binary and ternary mixtures in tens of seconds.
Abstract: Most of the reported optofluidic devices analyze liquid by measuring its refractive index. Recently, the wettability of liquid on various substrates has also been used as a key sensing parameter in...
8 citations
01 Aug 2018
TL;DR: In this article, a flexible touch panel combing single-walled carbon nanotubes and triboelectric effect to reach high performance has been reported for Internet-of-things applications.
Abstract: Flexible electronics, as a cutting-edge field in modern electronics, has drawn more and more attentions for its applications in internet-of-things. Flexible touch sensors, as one type of fundamental devices, always play a significant role in this field. Here, we reported a flexible touch panel combing single-walled carbon nanotubes and triboelectric effect to reach high performance.