Circularly polarized light (CPL) is central to photonic technologies. A key challenge lies in developing a general route for generation of CPL with tailored chiroptical activity using low-cost raw materials suitable for scale-up. This study presents that cellulose films with photonic bandgaps (PBG) and left-handed helical sense have an intrinsic ability for circular polarization leading to PBG-based CPL with extraordinary |g | values, well-defiend handedness, and tailorable wavelength by the PBG change. Using such cellulose films, incident light ranging from near-UV to near-IR can be transformed to passive L-CPL and R-CPL with viewing-side-dependent handedness and |g | values up to 0.87, and spontaneous emission transformed to R-CPL emission with |g | values up to 0.68. Unprecedented evidence is presented with theoretical underpinning that the PBG effect can stimulate the R-CPL emission. The potential of cellulose-based CPL films for polarization-based encryption is illustrated. The evaporation-induced self-assembly coupled with nanoscale mesogens of cellulose nanocrystals opens new venues for technological advances and enables a versatile strategy for rational design and scalable manufacturing of organic and inorganic CPL films for photonic applications.
We synthesized a series of polycrystalline YbCd2−xZnxSb2 (x=0, 0.4, 0.8, 1, 1.2, 1.6, and 2) samples and measured their thermoelectric properties. Thermoelectric figure of merit ZT at 700K is higher than 1.0 for Cd-rich samples (x=0, 0.4, 0.8, and 1.0) and Zn substitute of Cd in YbCd2Sb2 can easily tune carrier concentration and reduce thermal conductivity. When x=0.4, sample exhibits the highest power factor (12–20μWcm−1K−2), the lowest lattice thermal conductivity (1.0Wm−1K−1 at 300K), highest ZT (1.2 at 700K), and best “self-compatibility.” The first principles calculations were performed to study the influences of bonding and electronic structures on physical properties.
A simple and general platform for thermochromic fluorescent materials with excellent performance and multiple feasible applications.
Multicolor organic electrochromic materials are important for the generation of full-color devices. However, achieving multiple colors using a single-molecule material has proved challenging. In this study, a multicolor electrochromic prototype device is generated by integrating medium engineering/in situ 'electro base'/laminated electrode technologies with the simple flying fish-shaped methyl ketone TM1. This multicolor electrochromic (green, blue and magenta) device is durable and has a high coloration efficiency (350 cm 2 C 21 ), a fast switching time (50 ms) and superior reversibility. This study is a successful attempt to integrate solvatochromism and basochromism in an electronic display. This integration not only introduces a new avenue for color tuning, in addition to the structural design of the colorant, but will also inspire further developments in the tuning of many other properties by this medium engineering approach, such as conductance and the redox property, and thereby accelerate versatile applications in data recording, ultrathin flexible displays, and optical communication and sensing. Keywords: electrochromic materials; laminated electrodes; microenvironment; multicolor devices; solvatochromic materials INTRODUCTION Owing to the increasing demand for low-power, ultrathin, flexible electronic displays, organic electrochromic materials 1-3 have become a research focus because of their distinct merits: low weight, high contrast, wide viewing angle, flexibility and the potential for low power consumption. Because the realization of a multicolor switch is preferred in the majority of their applications in displays, 4-10 various electrochromic materials including polymers, 11,12 small organic molecules 13,14 and metal-organic complexes, 15 and technologies aimed at multicolor switches have been intensively explored. Transition metals based on metal-organic complex multicolor electrochromic materials exhibit attractive properties, such as high stability and chemiluminescence. 16 However, the expense and scarcity of the precious metals, such as ruthenium, 15,16 osmium 17 and iridium, 18 limit their practical applications. Polymeric multicolor electrochromic materials with different electrochromic activation units [19][20][21] possess the advantages of easy processing, diverse resources and facile color tunability. However, some intrinsic problems, such as the lack of colorless states, poor transparency, poor color purity and complicated synthesis procedures, hinder their applications. Compared with electrochromic polymers, small organic color switches possess the advantages of low cost, good color purity, distinct transition from colorless to colored states and fine tunability of their photoelectronic properties via easy structure modifications. The lack of multicolor abilities is their intrinsic
Converting CO 2 into fuels and other value-added chemicals via an electrochemical reduction method has recently attracted great interest. However, there are still challenges to find suitable catalysts with high selectivity toward the formic acid formation. Here, we report the bimetallic CuSn-based catalyst to reduce CO 2 to formic acid by optimizing the ratio of Cu to Sn to achieve the optimal selectivity. The catalyst is generated on laser-induced graphene. Among the catalysts, CuSn-4 with Cu/Sn atomic ratio close to 1:2 shows a faradaic efficiency of 99% toward formic acid with a high partial current density of 26 mA/cm 2 . Density functional theory calculations demonstrate that OCHO* intermediate formation is more favorable than that of COOH* on Sn sites, while OCHO* intermediate formation is moderate on Cu sites. The synergetic catalytic effect between Cu and Sn would further favor HCOOH formation. This study provides significant insight into the mechanism of formic acid formation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.