The achievement of structural color has shown advantages in large-gamut, high-saturation, high-brightness, and high-resolution. While a large number of plasmonic/dielectric nanostructures have been developed for structural color, the previous approaches fail to match all the above criterion simultaneously. Herein we utilize the Si metasurface to demonstrate an all-in-one solution for structural color. Due to the intrinsic material loss, the conventional Si metasurfaces only have a broadband reflection and a small gamut of 78% of sRGB. Once they are combined with a refractive index matching layer, the reflection bandwidth and the background reflection are both reduced, improving the brightness and the color purity significantly. Consequently, the experimentally demonstrated gamut has been increased to around 181.8% of sRGB, 135.6% of Adobe RGB, and 97.2% of Rec.2020. Meanwhile, high refractive index of silicon preserves the distinct color in a pixel with 2 × 2 array of nanodisks, giving a diffraction-limit resolution.

An efficient artificial light-harvesting system is fabricated from a cyclic polysaccharide, sulfato-β-cyclodextrin (SCD); an aggregation-induced emission molecule, an oligo(phenylenevinylene) derivative (OPV-I); and a fluorescent dye, nile red (NiR), via noncovalent interactions in an aqueous solution. In this system, the OPV-I/SCD supramolecular assembly acts as a donor, and NiR that is loaded into the OPV-I/SCD assembly acts as an acceptor. Significantly, an efficient energy-transfer process occurs between the OPV-I/SCD assembly and the loaded NiR, leading to an extremely high antenna effect.

BackgroundRed (R) and far-red (FR) light distinctly influence phytochrome-mediated initial tomato growth and development, and more recent evidence indicates that these spectra also modulate responses to a multitude of abiotic and biotic stresses. This research investigated whether different R: FR values affect tomato growth response and salinity tolerance. Tomato seedlings were exposed to different R: FR conditions (7.4, 1.2 and 0.8) under salinity stress (100 mM NaCl), and evaluated for their growth, biochemical changes, active reactive oxygen species (ROS) and ROS scavenging enzymes, pigments, rate of photosynthesis, and chlorophyll fluorescence.ResultsThe results showed that under conditions of salinity, tomato seedlings subjected to a lower R: FR value (0.8) significantly increased both their growth, proline content, chlorophyll content and net photosynthesis rate (Pn), while they decreased malondialdehyde (MDA) compared to the higher R: FR value (7.4). Under conditions of salinity, the lower R: FR value caused a decrease in both the superoxide anion (O2•−) and in hydrogen peroxide (H2O2) generation, an increase in the activities of superoxidase dismutase (SOD, EC 1.15.1.1), peroxidase (POD, EC 1.11.1.7) and catalase (CAT, EC 1.11.1.7). Tomato seedlings grown under the lower R: FR value and conditions of salinity showed a higher actual quantum yield of photosynthesis (ΦPSII), electron transport rate (ETR), and photochemical quenching (qP) than those exposed to a higher R: FR, indicating overall healthier growth. However, the salinity tolerance induced at the lower R: FR condition disappeared in the tomato phyB1 mutant.ConlusionThese results suggest that growing tomato with a lower R: FR value could improve seedlings’ salinity tolerance, and phytochrome B1 play an very important role in this process. Therefore, different qualities of light can be used to efficiently develop abiotic stress tolerance in tomato cultivation.

No abstract

The pursuit of high-performance photodetectors functioning in the solar-blind spectrum is motivated by both scientific and practical applications ranging from secure communication, monitoring, sensing, etc. In particular, the fabrication of heterojunctions based on the wide band gap semiconductors has emerged as an attractive strategy to promote the high-efficient photogenerated electron/hole pair separation. However, the precisely controlled growth of heterojunctions remains a huge challenge. The lattice mismatch leads to the formation of defects and/or dislocations at the interface, deteriorating the performance of devices and limiting their envisioned applications. Here, we demonstrate a simple one-step growth of amorphous/crystalline Ga2O3 phase junctions by using sputtering technique, yielding a large responsivity of 0.81 A/W, a superior photo-to-dark current ratio over 107, and an ultrahigh response speed of ∼12 ns. Compared to the previous reported solar-blind photodetectors, the obtained detectivity ≈ 5.67 × 1014 Jones is increased by 2 orders of magnitude. Such excellent photoresponse characteristics can be understood by the interfacial built-in field-promoted electron/hole pair separation for the amorphous/crystalline Ga2O3 phase junctions. Our results provide a novel path toward realizing high-performance optoelectronics functioning in the solar-blind spectrum.

Charge carrier trapping phosphors are one of the most fascinating candidates for next‐generation optical information storage technology and advanced anti‐counterfeiting applications. However, there is a challenge in that shallow traps can result in interference with the real‐time reading of optical information, and the anti‐counterfeiting level also needs to be further enhanced. Here, a novel quasi‐layer‐structured Ca3Ga4O9:Bi3+ phosphor is introduced to address this challenge, based on the targeted recombination phenomenon. This material shows turning electron‐trapping ability and obvious differences in photoluminescence, long persistent luminescence, and photo‐stimulated luminescence processes, which are beneficial in achieving information reading without interference and provide multiple anti‐counterfeiting. As a proof of concept, information reading without interference is experimentally achieved by choosing an appropriate filter and excitation wavelength, and multiple anti‐counterfeiting applications are demonstrated using a simple seal‐photocopy method. The results indicate that the targeted recombination strategy is very effective for achieving multifunctional applications of charge carrier trapping phosphors.

Optical data storage technology has many advantages over the traditional solid-state and magnetic storage technology, such as low cost, multi-dimensional storage, and rewritable capability. Therefore, the optical data storage technology has been in increasing demand for optical storage media. Herein, the photochromic and photoluminescence properties of BaMgSiO 4 :Bi 3+ ceramics were investigated. The BaMgSiO4:Bi3+ ceramics showed reversible photochromism from gray to pink upon alternating the 254 nm ultraviolet light and 532 nm laser irradiation. This is caused by the electron trapping and de-trapping in the oxygen vacancies of the BaMgSiO 4 :Bi 3+ host. This reversible behavior of photochromism was applied to fabricate different patterns on the surface of the BaMgSiO 4 :Bi 3+ ceramics, which exhibited the reversible dual-mode optical information recording and erasing abilities. The photoluminescence reversible modulation of the BaMgSiO 4 :Bi 3+ ceramics was obtained through the photochromic phenomenon. This modification behavior of luminescence could be applied to read-out the recording information in the BaMgSiO 4 :Bi 3+ ceramics. The coloration and bleaching of BaMgSiO 4 :Bi 3+ ceramics were dependent on the time of light stimulation, which facilitated multiplexing encoding. This photoluminescence and photochromism multiplexing of the BaMgSiO 4 :Bi 3+ ceramics enhanced the optical data storage capability.

Random effects or mixed logit models are often used to model differences in consumer preferences. Data from choice experiments are needed to estimate the mean vector and the variances of the multivariate heterogeneity distribution involved. In this paper, an efficient algorithm is proposed to construct semi-Bayesian -optimal mixed logit designs that take into account the uncertainty about the mean vector of the distribution. These designs are compared to locally -optimal mixed logit designs, Bayesian and locally -optimal designs for the multinomial logit model and to nearly orthogonal designs (Sawtooth (CBC)) for a wide range of parameter values. It is found that the semi-Bayesian mixed logit designs outperform the competing designs not only in terms of estimation efficiency but also in terms of prediction accuracy. In particular, it is shown that assuming large prior values for the variance parameters for constructing semi-Bayesian mixed logit designs is most robust against the misspecification of the prior mean vector. In addition, the semi-Bayesian mixed logit designs are compared to the fully Bayesian mixed logit designs, which take also into account the uncertainty about the variances in the heterogeneity distribution and which can be constructed only using prohibitively large computing power. The differences in estimation and prediction accuracy turn out to be rather small in most cases, which indicates that the semi-Bayesian approach is currently the most appropriate one if one needs to estimate mixed logit models.semi-Bayesian mixed logit design, fully Bayesian mixed logit design, heterogeneity, prediction accuracy, multinomial logit design, model-robust design, -optimality, design construction algorithm