Sasa Wang

Multifunctional Radical-Doped Polyoxometalate-Based Host–Guest Material: Photochromism and Photocatalytic Activity

An effective strategy to synthesize multifunctional materials is the incorporation of functional organic moieties and metal oxide clusters via self-assembly. A rare multifunctional radical-doped zinc-based host-guest crystalline material was synthesized with a fast-responsive reversible ultraviolet visible light photochromism, photocontrolled tunable luminescence, and highly selective photocatalytic oxidation of benzylic alcohols as a result of blending of distinctively different functional components, naphthalenediimide tectons, and polyoxometalates (POMs). It is highly unique to link π-electron-deficient organic tectons and POMs by unusual POMs anion-π interactions, which are not only conducive to keeping the independence of each component but also effectively promoting the charge transfer or exchange among the components to realize the fast-responsive photochromism, photocontrolled tunable luminescence, and photocatalytic activity.

Tailored Engineering of an Unusual (C4H9NH3)2(CH3NH3)2Pb3Br10 Two-Dimensional Multilayered Perovskite Ferroelectric for a High-Performance Photodetector

Two-dimensional (2D) layered hybrid perovskites have shown great potential in optoelectronics, owing to their unique physical attributes. However, 2D hybrid perovskite ferroelectrics remain rare. The first hybrid ferroelectric with unusual 2D multilayered perovskite framework, (C4 H9 NH3 )2 (CH3 NH3 )2 Pb3 Br10 (1), has been constructed by tailored alloying of the mixed organic cations into 3D prototype of CH3 NH3 PbBr3 . Ferroelectricity is created through molecular reorientation and synergic ordering of organic moieties, which are unprecedented for the known 2D multilayered hybrid perovskites. Single-crystal photodetectors of 1 exhibit fascinating performances, including extremely low dark currents (ca. 10-12  A), large on/off current ratios (ca. 2.5×103 ), and very fast response rate (ca. 150 μs). These merits are superior to integrated detectors of other 2D perovskites, and compete with the most active CH3 NH3 PbI3 .

Rapid production and field testing of homozygous transgenic tobacco lines with virus resistance conferred by expression of satellite RNA and coat protein of cucumber mosaic virus

A procedure for the fast production of homozygotic transgenic plants was developed. Leaf discs of haploid tobacco plants from anther cultures were transformed with a chimaeric vector containing coat protein (CP) and satellite RNA (Sat-RNA) genes from cucumber mosaic virus (CMV). One-hundred-and-twelve Kanamycin-resistant transformed haploid plants were subjected to selection based on the expression of both CP and Sat-RNA. Eighty-nine transgenic plants expressing both genes were selected and tested for their resistance to CMV by inoculation with high concentration of CMV (200 μg ml−1). Only five plants showed no symptoms of viral infection 30 days after inoculation. These plants were then diploidized by colchicine treatment. Three homozygous diploid lines with high levels of resistance to CMV were obtained after only one generation. The three transgenic lines were further tested under field conditions. The results showed that the progenies of these transgenic lines were homozygous and were highly resistant to CMV under natural field infection and manual inoculation conditions.

A semi-conductive organic–inorganic hybrid emits pure white light with an ultrahigh color rendering index

White-light emission has evoked great attention as one of the most promising technologies in the applications of solid-state lighting devices, light emitting diodes, and flat-panel displays. However, up to now, pure white-light emitting materials have rarely been reported. Here, we present a single-component white-light emitting semiconductor, [C5H9–NH3]4CdBr6, which exhibits CIE chromaticity coordinates of (0.33, 0.33). Notably, this value is the same as that of the standard pure white-light emission. Remarkably, it shows an ultrahigh color rendering index of 92.5, which exceeds that of mixed-phosphor light sources and is comparable to the recently reported highest one among single-component materials. Mechanistic studies indicate that the white-light emission originates from the synergetic effect of deep defects coupled with the organic component. Such an organic–inorganic hybrid with outstanding color characteristics will pave a new approach in the development of white-light emitting materials with practical applications.

Broadband white-light emission with a high color rendering index in a two-dimensional organic–inorganic hybrid perovskite

Two-dimensional (2D) organic–inorganic hybrid layered perovskites have attracted increasing attention as promising candidates in optoelectronics, due to their excellent physical attributes. However, although great efforts have been made, broadband white-light emission with a high color rendering index based on 2D hybrid perovskites still remains rare. Here, we report a broadband white-light emissive 2D organic–inorganic hybrid (110)-oriented perovskite, N-(3-aminopropyl)imidazole tetrachloro-lead (1), in which the 2D corrugated layered inorganic framework is formed by corner-shared highly distorted lead chloride octahedra. Remarkably, the color rendering index of 1 is up to 93, which is superior to that of previously reported broadband white-light emission in 2D organic–inorganic hybrid perovskites. Such a 2D hybrid layered perovskite material with a high color rendering index may provide potential applications in white light-emitting diodes.

Broad-Band-Emissive Organic–Inorganic Hybrid Semiconducting Nanowires Based on an ABX3-Type Chain Compound

Organic-inorganic hybrid lead halide (e.g., CH3NH3PbX3, where X = CI, Br, and I) nanowires (NWs) with remarkable electric and optical properties have recently garnered increasing attention, owing to their structural flexibility and tunability compared to inorganic semiconducting NWs. While most recently reported NWs are limited to methylammonium/formamidinium three-dimensional lead halide perovskites, it is urgent to develop new organic-inorganic hybrid semiconducting NWs. Here, broad-band-emissive single-crystal semiconductive NWs based on a new ABX3-type organic-inorganic chain hybrid, (2-methylpiperidine)lead tribromide, are reported. It is believed that this work will enrich the organic-inorganic hybrid semiconducting NWs and may provide potential applications for LED displaying.

(2-Methylpiperidine)PbI3: an ABX3-type organic–inorganic hybrid chain compound and its semiconducting nanowires with photoconductive properties

Organic–inorganic hybrid semiconducting nanowires have recently been widely regarded as promising candidates for electric and optical applications due to their faster carrier separation and low charge recombination. Here, we reported organic–inorganic hybrid semiconducting nanowires with photoconductive properties based on a one dimensional ABX3-type compound, (2-methylpiperidine)PbI3 (1). In 1, one dimensional infinite double chains are surrounded by protonated organic 2-methylpiperidine cations to form a quantum wire structure, which has been thought to be favorable for carrier transport. Furthermore, the prepared semiconducting nanowires of 1 display obvious photoconductive properties, which have been verified using I–V and time-dependent photoresponse measurements. All the results indicate that such semiconducting nanowires based on low dimensional organic–inorganic hybrid materials have potential photoelectric applications.

Bilayered Hybrid Perovskite Ferroelectric with Giant Two-Photon Absorption

Perovskite ferroelectrics with prominent nonlinear optical absorption have attracted great attention in the field of photonics. However, they are traditionally dominated by inorganic oxides and exhibit relatively small nonlinear optical absorption coefficients, which hinder their further applications. Herein, we report a new organic-inorganic hybrid bilayered perovskite ferroelectric, (C4H9NH3)2(NH2CHNH2)Pb2Br7 (1), showing an above-room-temperature Curie temperature (∼322 K) and notable spontaneous polarization (∼3.8 μC cm-2). Significantly, the unique quantum-well structure of 1 results in intriguing two-photon absorption properties with a giant nonlinear optical absorption coefficient as high as 5.76 × 103 cm GW-1, which is almost two-orders of magnitude larger than those of mostly traditional all-inorganic perovskite ferroelectrics. To our best knowledge, 1 is the first example of hybrid ferroelectrics with giant two-photon absorption coefficient. The mechanisms for ferroelectric and two-photon absorption are revealed. This work will shed light on the design of new ferroelectrics with two-photon absorption and promote their potentials in the photonic application.

Li8NaRb3(SO4)6·2H2O as a new sulfate deep-ultraviolet nonlinear optical material

Sulfates have long been ignored as nonlinear optical materials over the past decades. Here we report a new sulfate deep-ultraviolet nonlinear optical material Li8NaRb3(SO4)6·2H2O synthesized by the facile water solution method. It crystallizes in the asymmetric monoclinic space group C2 (No. 5). Its single-crystal structure features a three-dimensional framework made up of SO4 and LiO4 tetrahedra. Powder second-harmonic generation tests demonstrate that Li8NaRb3(SO4)6·2H2O is phase-matchable with a second-harmonic generation response of about 0.5 × KH2PO4. Ultraviolet-visible-near-infrared diffuse reflectance spectra illustrate that the ultraviolet cutoff edge of Li8NaRb3(SO4)6·2H2O may be as low as λ < 190 nm. Theoretical calculations reveal that the optical properties of Li8NaRb3(SO4)6·2H2O are mainly attributed to S–O groups. All these results reveal that Li8NaRb3(SO4)6·2H2O may possess potential use in the deep-ultraviolet nonlinear optics field. We believe that the discoveries in our work will attract scientists’ attention to sulfate systems for their potential as deep-ultraviolet nonlinear optical materials.

Above-room-temperature switching of quadratic nonlinear optical properties in a Bi–halide organic–inorganic hybrid

Organic–inorganic hybrid nonlinear optical (NLO) switches have recently attracted intensive attention as potential candidates for optical applications. Herein, by introducing an organic triamine cation, we obtain a lead-free Bi-based organic–inorganic hybrid, (C4H16N3)BiBr6 (1), which behaves as a promising above-room-temperature modulator of quadratic NLO responses. More importantly, 1 possesses a remarkable NLO switching contrast of up to ∼35 and a notable switching repeatability. Additionally, microscopic single-crystal structural analyses reveal that the coordinated distortion of inorganic [BiBr6]3− octahedra and the order–disorder transformation of the flexible organic triamine cations synergistically contribute to its NLO switching behavior. We believe that this work will promote the development of high-performance NLO switching materials based on devisable organic–inorganic metal–halide hybrids.