Constructing on-demand single/multi-color transitioning fabrics with photocatalysis/photothermal-armed deficient semiconductors

On-demand color switching systems that utilize synchronized semiconductor-catalyzed reduction and photothermal-accelerated oxidation in liquid/solid are highly appealing.Herein,on-demand single/multi-color switching fabrics have been constructed by using defective SnO_(2):Sb-based color switching systems.SnO_(2):Sb nanocrystals with the suitable doping concentration accord lattices with abundant free electrons,conferring high photocatalytic and photothermal performances.A well-crafted set of dual light-responsive semiconductor-catalyzed systems with rapid color change can be attained via the homogenous mixture of SnO_(2):Sb with suitable redox dyes to produce single-color(RGB(red,green,blue))and multi-color transitioning(purple and green)systems.The illumination of these systems by 450 nm light triggers rapid photocatalytic discoloration,while irradiation by 980 nm light confers the photothermal effect that accelerates recoloration in air.Besides,the inks can be extended to rewritable fabrics by embedding the nanocrystals and redox dyes into hydroxyethyl cellulose(as the polymer matrix)and then coating on hydrophobic cotton fabrics to produce photo-switchable fabrics with excellent single/multi-color response.By exploiting the dual light interactions with the semiconductor-mediated systems,various images/letters can be remotely printed and erased on the rewritable fabrics which show promise for potential applications as information storage media and visual sensors.Importantly,the present rewritable fabric shows good stability and reversibility.The present work provides insights into the development of novel color-switching materials.

Defect Properties of GaAs by Positron Annihilation

Positron lifetime and Doppler Broadening spectra have been measured for three types of GaAs semiconductors. Direct evidence of native vacancy-type defects is found in the semi--insulating (SI-type) and n-type sample as its average lifetime Tin and S-parameter are larger than the bulk value. No positron trapping occurred in p-type GaAs. The lifetime spectrum of n-GaAs has also been measured as a function of temperature. The increase in average lifetime τm from 226 ps to 234 ps at the temperature range 95-330 K was observed and was explained by the ionization of the vacancy. The slight increase in bulk lifetime τb with the temperature was caused by the latticeexpansion and expansion coefficient α=14×10-6-1 was evaluated.

Clarifying the atomic origin of electron killers in β-Ga_(2)O_(3) from the first-principles study of electron capture rates

The emerging wide bandgap semiconductorβ-Ga_(2)O_(3) has attracted great interest due to its promising applications for high-power electronic devices and solar-blind ultraviolet photodetectors.Deep-level defects inβ-Ga_(2)O_(3) have been intensively studied towards improving device performance.Deep-level signatures E_(1),E_(2),and E_(3) with energy positions of 0.55–0.63,0.74–0.81,and 1.01–1.10 eV below the conduction band minimum have frequently been observed and extensively investigated,but their atomic origins are still under debate.In this work,we attempt to clarify these deep-level signatures from the comparison of theoretically predicted electron capture cross-sections of suggested candidates,Ti and Fe substituting Ga on a tetrahedral site(Ti_(GaI) and Fe_(GaI))and an octahedral site(Ti_(GaII) and Fe_(GaII)),to experimentally measured results.The first-principles approach predicted electron capture cross-sections of Ti_(GaI) and Ti_(GaII) defects are 8.56×10^(–14) and 2.97×10^(–13) cm^(2),in good agreement with the experimental values of E_(1) and E_(3) centers,respectively.We,therefore,confirmed that E_(1) and E_(3) centers are indeed associated with Ti_(GaI) and Ti_(GaII) defects,respectively.Whereas the predicted electron capture cross-sections of Fe_(Ga) defect are two orders of magnitude larger than the experimental value of the E_(2),indicating E_(2) may have other origins like C_(Ga) and Ga_(i),rather than common believed Fe_(Ga).

Intrinsic vacancy in 2D defective semiconductor In_(2)S_(3) for artificial photonic nociceptor

It is crucial to develop an advanced artificially intelligent optoelectronic information system that accurately simulates photonic nociceptors like the activation process of a human visual nociceptive pathway.Visible light reaches the retina for human visual perception,but its excessive exposure can damage nearby tissues.However,there are relatively few reports on visible light–triggered nociceptors.Here,we introduce a two-dimensional natural defectiveⅢ–Ⅵsemiconductorβ-In_(2)S_(3)and utilize its broad spectral response,including visible light brought by intrinsic defects,for visible light–triggered artificial photonic nociceptors.The response mode of the device,under visible light excitation,is very similar to that of the human eye.It perfectly reproduces the pain perception characteristics of the human visual system,such as‘threshold,’‘relaxation,’‘no adaptation’,and‘sensitization’.Its working principle is attributed to the mechanism of charge trapping associated with the intrinsic vacancies in In_(2)S_(3)nanosheets.This work provides an attractive material system(intrinsic defective semiconductors)for broadband artificial photonic nociceptors.