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AgBiS2 has been considered by researchers as a new-generation photovoltaic material because of its ideal bandgap, environment-friendliness and wide absorption range. Although it has shown great development potential in solar cell devices, due to the lack of systematic exploration and research on precursor solution chemistry, the performance of AgBiS2 solar cells prepared by the precursor solution method lags behind those of colloidal solution–processed cells. Herein, we report a pre-nucleation strategy that involves controlling the precursor solution at the molecular level. The pre-nucleation strategy results in faster nucleation of the AgBiS2 crystals during crystallization, resulting in AgBiS2 thin films with larger grains, fewer defects and more homogeneous cation disorder. The improved quality of the AgBiS2 thin films resulted in high-performance AgBiS2 thin film solar cells with a JSC of up to 30.9 mA cm−2 and a record high PCE of 3.68%. This work provides a feasible method for the preparation of AgBiS2 thin film solar cells based on the precursor solution. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) with a high specific surface area show efficient activity for the reduction of nitroaromatics. In this study, single-stranded DNA chains (ssDNA, T30, C30 or A30) were used as templates to mediate the formation of AuNPs, and the results demonstrated that the morphologies of the C30-AuNPs or A30-AuNPs had more abundant irregular features than the T30-AuNPs. The catalytic properties and applications of the C30-AuNPs were systematically examined using a reaction model for the reduction of 4-nitrophenol by NaBH4. The effect of different temperatures and pH values on the catalytic activity of C30-AuNPs have been investigated. The C30-AuNPs showed the highest catalytic activity (rate constant kapp = 0.2221 min−1) for the reduction of 4-NP at 35 °C and pH = 7. The conversion of 4-NP to 4-AP using C30-AuNPs followed the Langmuir–Hinshelwood mechanism, which was explained by the principle of promoting electron transfer, i.e. the surface of C30-AuNPs is rich in active sites that promote the process of electron transfer from BH4− to 4-NP, completing the conversion of 4-nitrophenol to 4-aminophenol. Furthermore, the results confirmed that C30-AuNPs were versatile for catalyzing isomers of 4-NP and azo dyes, such as 2-NP, 3-NP, MO, CR and EBT. The results offer new insights into the construction of Au-based catalysts for efficiently removing environmental pollutants. [ABSTRACT FROM AUTHOR]

The design of thermostable phosphor is still a pivotal challenge in pc-WLED applications. Herein, an efficient strategy is proposed to design excellent thermostable red emission in the singly Mn2+-doped near-zero thermal expansion (NZTE) material Li2Zn3(P2O7)2. Under the excitation of 412 nm wavelength, the emission could be tuned from 636 to 672 nm by increasing the Mn2+-doping level via synthetic effects among the crystal field, the exchange coupling interaction in Mn–Mn dimers, and energy transfer in different luminescence centers. The PL intensity of LZPO:Mn2+ could be maintained at 97% at 150 °C and 94% at 200 °C of its initial intensity at room temperature. During the heating process, LZPO presented near-zero thermal expansion, contributing to the nearly unaffected PL intensity. The emission loss was also compensated by trap-assisted energy transfer to the luminescent center. This study not only offers a perspective idea for elucidating the correlation between the crystal structure and optical properties, but also opens a new way of designing excellent thermostable luminescent materials based on NZTE materials in self-reduction systems. [ABSTRACT FROM AUTHOR]

All-inorganic perovskite CsPbBr3 has been regarded as a new semiconductor radiation material with great potential due to its excellent carrier transport performance and thermal stability. However, it remains challenging to optimize the size and quality of CsPbBr3 single crystals for commercial applications. Here, the [100], [010], and [001] orientations of bulk CsPbBr3 single crystals were examined, and their anisotropic X-ray detection performance was investigated. The regular positive and negative charge distributions at the outer (010) surface and the connection of [PbBr6]4− octahedrons with the [010] orientation contribute to decreased defect densities and enhanced carrier transportation of the (010) facet. Additionally, the wafer with the [010] orientation exhibited the weakest ion migration among the three orientations due to the largest active energy (143.77 meV) and ion diffusion barrier energy (0.361 eV), which is advantageous for enhancing the X-ray response. Moreover, the (010) CsPbBr3 single crystal detector, which was fabricated with EGaIn and Au electrons, demonstrated the maximum sensitivity of 34 449 μC Gyair−1 cm−2 under a high bias voltage of −400 V and the lowest detection limit of 52.6 nGyair s−1 compared with the other two devices. This work highlights the anisotropic engineering of large-size single crystals for boosting perovskite radiation performance and provides valuable advice for the oriented growth of large-size crystals and films. [ABSTRACT FROM AUTHOR]

Mercurous halide crystals, which crystallize in a one-dimensional chain-like structure, have attracted great attention as polarizing and acousto-optic devices in the long wave infrared range for their large birefringence, a wide transparent range, and a large acousto-optic figure of merit. However, it is difficult to obtain large-size single crystals with high quality due to the severe layered cleavage nature of crystals. Additionally, crystal processing still remains a challenge owing to the soft brittleness and cleavage nature. To date, high-quality, large-size mercury halide crystals have been successfully obtained by our group. Herein, micro-striations in the (001) surface of the mercury halide crystals caused by the cleavage along the 〈110〉 orientation in mechanical polishing were reported for the first time. The crystal micro-striations act as diffraction gratings, producing "diffraction spots" when illuminated by light. These cleavage striations seriously deteriorate the crystal crystallinity, enlarging the full width at half maximum (FWHM) of the X-ray rocking curves for the polished surfaces. But the striations on the crystal surface can be effectively attenuated by optimizing the polishing process. The discovery and effective suppression of micro-striations in mercurous halide crystals lay a solid foundation for the fabrication of polarizing and acousto-optic devices with high performance in the long-waved infrared range. [ABSTRACT FROM AUTHOR]

Established decarboxylative Minisci reactions are limited to aliphatic carboxylic acids, as their analogs, silanecarboxylic acids, have been rarely investigated. Herein, we present a new decarboxylative Minisci-type reaction of N-heteroarenes with silanecarboxylic acids under photo- or silver-mediated conditions. This C–H silylation strategy provides efficient access to diverse N-heteroarylsilanes in moderate to excellent yields with high regioselectivity, among which Ag-catalysed decarboxylation of silanecarboxylic acids furnishes an unprecedented method for silyl radical generation. [ABSTRACT FROM AUTHOR]

Here we constructed a series of novel non-centrosymmetric structure phosphors [Rb2Zn3(P2O7)2:Mn2+] by a high-temperature solid-state reaction. The multiband emission can be designed by Mn2+ preferentially occupying three types of crystallographic sites in Rb2Zn3(P2O7)2:Mn2+. The emission color could be continuously tuned from yellow-green to orange-red via multiple synergies among crystallographic site engineering, energy transfer, and Mn–Mn dimmers alone through the dopant concentration. These color-tunable phosphors have good thermal stability (I150 °C/I25 °C = 91%). The as-prepared pc-WLED has a low corresponding color temperature (CCT = 4820 K) and a high color rendering index (Ra = 90.4) with CIE color coordinates of (0.351, 0.358). These results show that emission-tunable Rb2Zn3(P2O7)2:xMn2+ phosphors are potential candidates for application in n-UV-based pc-WLED devices. This study offers a new insight for wide-range tuning of PL properties by using crystallographic site engineering through changing the doping level in Mn-activated phosphors. [ABSTRACT FROM AUTHOR]

Immigration to Mars, which is expected to be powered mainly by photovoltaics, is one of the greatest dreams of humanity. However, the extreme temperature difference and high-energy cosmic radiation on the surface of Mars make it difficult for conventional photovoltaics to operate steadily over time. With their advantages of being lightweight, having a high irradiation tolerance, and an outstanding power conversion efficiency (PCE), perovskite solar cells (PSCs) have shown themselves to be a promising candidate for Martian applications. In this study, we simulated the low-intensity–low-temperature (LILT) environment of the Mars surface, and monitored the in situ device performance of PSCs. Surprisingly, the device PCE was not only maintained at a high level but was even improved slightly. Further investigation revealed that the self-healing effect of perovskites under LILT conditions could be attributed to the light-induced decomposition of the perovskite film and the β-phase perovskite recrystallization process at the perovskite/hole transport layer interface. Interfacial β-phase perovskites are stable at low temperatures, which can facilitate charge extraction and protect the perovskite bulk from long-term light damage. This study demonstrated the feasibility of PSCs and provides a reference for Martian applications. [ABSTRACT FROM AUTHOR]

The application of lithium–sulfur (Li–S) batteries is hindered by the severe shuttle effect and sluggish redox conversion kinetics of lithium polysulfides (LiPSs). Herein, holey amorphous dual transition metal (cobalt and iron) oxide-coated black phosphorus nanosheets (BP@FeCoO) have been synthesized and utilized as a sulfur host in Li–S batteries. From the compositional outlook, compared with the individual counterparts, the hybrid material of BP and amorphous FeCoO containing rich oxygen vacancies has enhanced adsorption ability and catalytic activity toward LiPSs, as well as improved electrical conductivity and Li-ion diffusion rate. From the structural feature perspective, the 2D nanosheets decorated with abundant meso/microporous channels greatly enlarge the surface area of the BP@FeCoO electrode, which offers sufficient active sites for accommodating sulfur active species and provides buffer space to withstand the volume changes during the charge/discharge process. Due to these compositional and structural superiorities, the Li–S battery with BP@FeCoO/S electrode exhibited excellent electrochemical performance with high cycle stability (fading rate of 0.040% per cycle at 1C) and outstanding rate capability (644.3 mA h g−1 at 5C). More impressively, with a high sulfur loading of 6.0 mg cm−2, the BP@FeCoO/S electrode showed a high capacity of 903.9 mA h g−1 at 0.2C. [ABSTRACT FROM AUTHOR]

Narrowband photodetectors are critical for the application of sensors in imaging systems, spectroscopic photodetectors, and optical communication. All-inorganic mixed-halide perovskite (CsPbBr3−3nX3n, X = Cl, I) crystals have emerged as outstanding wavelength-selective light detection materials. They exhibit tunable optoelectronic properties and high stability, and can realize color discrimination without a filter or a bulk spectrometer. This study demonstrates the successful fabrication of a series of centimeter-sized mixed-halide perovskite (CsPbBr3−3nX3n) single crystals using the modified Bridgman method. The optical absorption edges of these crystals are continuously tuned from 437 to 664 nm, corresponding to the bandgaps of 2.88–1.90 eV, by changing the halide composition. Subsequently, eight filter-free narrowband photodetectors are fabricated based on the CsPbBr3−3nX3n bulk crystals. The narrowband photodetectors exhibit a widely tunable response range from violet to orange, a full-width at half-maximum of <20 nm, and an optimal responsivity of 0.59 A W−1, which demonstrates excellent spectral discrimination capabilities. Finally, a filter-free color image sensor, which is integrated with the CsPbBr3−3nX3n narrowband photodetectors, is constructed. The sensor exhibits excellent color and shape recognition abilities. These results demonstrate the exciting potential of the all-inorganic mixed-halide perovskite bulk crystals for the fabrication of compact, high-performance filter-free color image sensors. [ABSTRACT FROM AUTHOR]

Prussian blue (PB) and its analogues (PBA) with different structures and adjustable compositions have been recognized as promising materials for catalysis, energy storage, and biological applications. Herein, a simple surface anchoring strategy is proposed to achieve the uniform deposition of CeO2 nanocrystals on the double-cone structure surface of PBA (denoted as Ce@Ce–Fe catalyst) for the selective catalytic reduction of NOx with NH3 (NH3-SCR). Compared with Ce–Fe and Ce@CeO2–Fe2O3, the Ce@Ce–Fe catalyst exhibited the best catalytic activity, widest working temperature window, and highest SO2 tolerance, implying its good application in the process of NH3-SCR. Moreover, the catalysts were characterized systematically to elucidate their surface properties and morphological structure. Taking advantage of the excellent redox performance, unique morphology, mesoporous structure with large surface area and pore diameter, and greater acid content, the Ce@Ce–Fe catalyst exhibited a higher NOx performance. In addition, the Ce@Ce–Fe catalyst also exhibited significant resistance to H2O and SO2 due to its higher content of Fe atoms, implying that Fe plays a critical role in this Ce–Fe based catalytic system. More importantly, the present study indicates that well-dispersed active components and unique architectures can effectively enhance the performance of catalysts. [ABSTRACT FROM AUTHOR]

Prussian blue (PB) and its analogues (PBA) with different structures and adjustable compositions have been recognized as promising materials for catalysis, energy storage, and biological applications. Herein, a simple surface anchoring strategy is proposed to achieve the uniform deposition of CeO2 nanocrystals on the double-cone structure surface of PBA (denoted as Ce@Ce–Fe catalyst) for the selective catalytic reduction of NOx with NH3 (NH3-SCR). Compared with Ce–Fe and Ce@CeO2–Fe2O3, the Ce@Ce–Fe catalyst exhibited the best catalytic activity, widest working temperature window, and highest SO2 tolerance, implying its good application in the process of NH3-SCR. Moreover, the catalysts were characterized systematically to elucidate their surface properties and morphological structure. Taking advantage of the excellent redox performance, unique morphology, mesoporous structure with large surface area and pore diameter, and greater acid content, the Ce@Ce–Fe catalyst exhibited a higher NOx performance. In addition, the Ce@Ce–Fe catalyst also exhibited significant resistance to H2O and SO2 due to its higher content of Fe atoms, implying that Fe plays a critical role in this Ce–Fe based catalytic system. More importantly, the present study indicates that well-dispersed active components and unique architectures can effectively enhance the performance of catalysts. [ABSTRACT FROM AUTHOR]

Double perovskites have attracted wide attention due to their low toxicity and good thermal stability. Doping with active elements is a promising method to endow perovskites with excellent optical, electrical or magnetic properties. Herein, a facile aqueous solution method is developed to synthesize Bi3+–Yb3+ co-doped Cs2Na0.6Ag0.4InCl6 double perovskite. Besides the intrinsic warm white self-trapped exciton (STE) emission that originated from the Cs2Na0.6Ag0.4InCl6 host, the samples also exhibit a strong near-infrared emission assigned to the 2F5/2 → 2F7/2 transition of octahedral coordinated Yb3+ ions upon excitation with ultraviolet light. The optimized sample shows a markedly high photoluminescence quantum yield of 84.7%. The photophysical studies such as photoluminescence (PL) and photoluminescence excitation spectra, temperature-dependent PL spectra, and PL decay curves reveal that the strong Yb3+ emission is attributed to the energy transfer from STEs to the Yb3+ ions. Finally, the lead-free double perovskite phosphor-converted LED containing visible and NIR regions was fabricated, with 8.92 mW output power at 100 mA drive current. The results show the great potential of the as-prepared crystals in optoelectronics applications. [ABSTRACT FROM AUTHOR]

In this work, a method of preparing boron nanoparticles using copper–boron alloy is presented, and the growth mechanism of boron nanoparticles is analyzed. It was found that sharp eutectic boron in copper–boron alloy can be spheroidized through adjustment of the cooling rate. By comparing three elements Al, Mg and Si, Mg can further control the morphology of eutectic boron and achieve further spheroidization of eutectic boron by limiting the emergence and growth of dendrites. Boron spheres as well as amorphous boron spheres were obtained by extracting the Cu–B alloy which had been spheroidized. The growth mechanism of eutectic boron and boron spheres has been analyzed by HRTEM. Solid boron spheres with curved lattice fringes and obvious crystal defects can be observed. Lattice puckering can be seen in amorphous boron spheres. Moreover, we also report a simple method to prepare hollow boron spheres which consist of multiple crystals and these crystals can form perfect coherent interfaces through twins. Twins and dislocations play an important role in the globular growth of boron. [ABSTRACT FROM AUTHOR]

High-quality perovskite films play a vital role in determining the performance of inverted perovskite solar cells. Here, for the first time, glucose is introduced to realize high quality MAPbI3 perovskite film, boosting the power conversion efficiency from 17.53% to 20.15% with an inverted planar configuration. In addition, all device parameters exhibit excellent reproducibility. More encouragingly, the current–voltage hysteresis is significantly suppressed in terms of the hysteresis index (control device: 0.083, glucose-modified device: 0.035). It is found that glucose could contribute to the enlargement of grain size and the decrease of grain boundaries in perovskite film. The decreased defect density and corresponding suppressed charge recombination account for the enchancement of Jsc and FF. Meanwhile, the stability of glucose-modified devices under conditions of heat, light and moisture is significantly improved. These findings indicate the eminent effects of glucose on performance optimization and stability enhancement of perovskite solar cells, which is potentially promising for other optoelectronic applications. [ABSTRACT FROM AUTHOR]

MnO2/Fe2O3 nanocomposites were achieved via using KMnO4 and FeCl3 as starting materials in aqueous solution followed by hydrothermal and high-temperature treatment processes. The hydrolysis of FeCl3 produces H+ ions to react with KMnO4 to produce MnO2, which further accelerates the hydrolysis process. The as-synthesized MnO2/Fe2O3 nanocomposites present high oxygen reduction reaction activity with an onset and half-wave potential of 0.953 and 0.859 V vs. RHE, respectively, and a limited current density of 4.875 mA cm−2 at 0.565 V, which are comparable to those of the commercial Pt/C catalyst. The excellent catalytic performance is considered to originate from the high Mn3+ content and the related oxygen vacancies. Furthermore, the unsatisfactory stability of the MnO2/Fe2O3 nanocomposites can be solved by coating with a layer of polyaniline-derived carbon. [ABSTRACT FROM AUTHOR]

A facile fractional crystallization technique was developed to prepare single crystalline CsPb2Br5 films using water as the solvent, and the films can be easily transferred onto various substrates for the device fabrication. The obtained films can be up to 600 × 600 μm2 and decrease to 50 nm in thickness with high crystalline quality as well as temperature and air stability. [ABSTRACT FROM AUTHOR]

The desired morphology, narrowed band gap and good photoelectric properties are the key factors for achieving the wide application of hybrid perovskite materials. During the preparation of novel hybrid perovskite materials, preserving the morphology of highly crystalline materials and narrowing their band gap will be desirable for designing photoelectric devices with outstanding performance. Here, with broad band gap 1D/2D hybrid perovskite single crystals as a template, we design a universal conversion process from single crystal to single crystal for a variety of large-sized hybrid perovskite materials induced by CH3NH2 (MA) gas under an ambient atmosphere. Most significantly, the hybrid perovskite single crystals keep their original morphology, narrow their optical band gap, and enhance their carrier mobility and photo-response dramatically after induced conversion by MA gas molecules, especially for DMAPbI3 (NH2(CH3)2PbI3). The optical band gap of DMAPbI3 was lowered from 2.58 eV to 1.53 eV and its photo-response performance was enhanced greatly by even a small amount of replacement of DMA+ by MA+, which provides a new idea for designing novel hybrid perovskite single crystals with a desired morphology and their optoelectronic devices with good performance. [ABSTRACT FROM AUTHOR]

In this paper, mesoporous carbon (meso-C) with three-dimensional mesoporous channels was synthesized through a nanocasting route using three-dimensional mesoporous silica KIT-6 as the template. Mesoporous carbon wrapped Pd–Fe nanocomposite catalysts were synthesized by the co-precipitation method. The effects of the experimental conditions, such as pH value, Fe loading content and calcination temperature, on CO oxidation were studied in detail. The prepared Pd–Fe/meso-C catalysts showed excellent catalytic activity after optimizing the experimental conditions. The surface tetravalent Pd content, existing forms of Fe species, surface chemical adsorbed oxygen concentration, and pore channels of mesoporous carbon played vital roles in achieving the highest performance for the Pd–Fe/meso-C catalyst. The reaction pathway was conjectured according to the XPS analysis of the Pd–Fe/meso-C catalysts for CO oxidation, which maybe adhered to the Langmuir–Hinshelwood + redox mechanism. The effect of moisture on CO conversion was investigated, and the superior Pd–Fe/meso-C catalyst could maintain its activity beyond 12 h. This catalyst also showed excellent activity compared to the reported values in the existing literature. [ABSTRACT FROM AUTHOR]

Clathrate hydrate particle agglomeration is often considered to be one of the key limiting factors in plug formation. The hydrate particle–water interaction can play a critical role in describing hydrate agglomeration, yet is severely underexplored. Therefore, this work investigates the interactions between water droplets and cyclopentane hydrate particles using a micromechanical force (MMF) apparatus. Specifically, the effect of contact time, temperature/subcooling, contact area, and the addition of Sorbitane monooleate (Span 80) surfactant on the water droplet–hydrate particle interaction behavior are studied. The measurements indicate that hydrate formation during the measurement would increase the water–hydrate interaction force significantly. The results also indicate that the contact time, subcooling and concentration of cyclopentane, which determine the hydrate formation rate and hydrate amount, will affect the hydrate–water interaction force. In addition, the interaction forces also increase with the water–hydrate contact area. The addition of Span 80 surfactant induces a change in the hydrate morphology and renders the interfaces stable versus unstable (leading to coalescence), and the contact force can affect the hydrate–water interaction behavior significantly. Compared with the hydrate–hydrate cohesion force (measured in cyclopentane), the hydrate–water adhesion force is an order of magnitude larger. These new measurements can help to provide new and critical insights into the hydrate agglomeration process and potential strategies to control this process. [ABSTRACT FROM AUTHOR]

The catalytic activity and the acrolein selectivity for liquid phase glycerol dehydration on β zeolites (HNa-β-k) were found to be dependent on the reaction temperature as well as on the amount of acid sites on the zeolites. An increase in the reaction temperature favors the acrolein selectivity. The acrolein selectivity increases with the Na+/H+ ratio and the glycerol conversion decreases with it so that a maximum acrolein yield is obtained when a certain amount of acidic sites are replaced by non-active Na+ sites. The computational results indicate that 3-hydoxylpropanal (HPA) is an important intermediate that determines the final product selectivity. The relative rates of the different reaction pathways for HPA can be affected by the amount of water molecules involved in its homogeneous reaction. Based on the reaction mechanism proposed, it was hypothesized that smaller pores reduce activity but increase selectivity to acrolein, and results of the H-MFI zeolite were consistent with this hypothesis. Our work provides important insight into the overall landscape of the reaction mechanism and can be used to help design reaction systems that have good acrolein selectivity for the liquid phase glycerol dehydration reactions. [ABSTRACT FROM AUTHOR]

An efficient and generally applicable protocol for the palladacycle-catalyzed arylation of diisopropyl H-phosphonate in water was developed. The remarkable features of this C–P bond-forming reaction include wide substrate scope including the inactive electron-rich and electron-neutral aryl chlorides, the weak inorganic base KF instead of strong bases such as KOtBu or NaOtBu for the activation of C–Cl bond, and the addition of isopropanol to avoid the decomposition of diisopropyl H-phosphonate. [ABSTRACT FROM AUTHOR]

A pH-controlled monophasic/biphasic switchable system has been developed as a green and novel strategy for homogeneous catalyst recycling, which has been successfully applied to the Cu-NHC-catalyzed carboxylation of organoboronic esters and benzoxazole with carbon dioxide. Additionally, the present strategy could also be extended to the Ag-NHC-catalyzed carboxylation of terminal alkyne. The tertiary amine-functionalized catalysts could be used for at least four times with a slight loss of activity. [ABSTRACT FROM AUTHOR]

The hydrosilylation of alkenes in a supercritical CO2(scCO2)/ionic liquid (IL) system was investigated. Rh(PPh3)3Cl exhibited excellent catalytic activity and selectivity. KOtBu was used as an additive, and no hydrogenation by-product (alkane) was detected in the scCO2/IL system. During hydrosilylation in the scCO2/IL system, the reactants were possibly transferred into the IL phase by scCO2, in which the catalyst was dissolved. The products can be flushed with scCO2after the reaction and the catalyst/IL system reused. [ABSTRACT FROM AUTHOR]

An unprecedented ruthenium catalysed [4+4] annulation of readily available benzoic acids and alkynes is reported for the first time. The carboxylate group acts as both a directing group and an internal nucleophilic reagent to facilitate a C(sp 2 )-H vinylation/annulation cascade. This reaction avoids the classically oxidative [4+2] annulation, allowing the efficient synthesis of a wide array of eight-membered lactones under oxidant-free conditions. Moreover, this catalytic system can be successfully extended to [4+3] and [4+5] annulations for the assembly of seven- and nine-membered lactones.

Double perovskites have attracted wide attention due to their low toxicity and good thermal stability. Doping with active elements is a promising method to endow perovskites with excellent optical, electrical or magnetic properties. Herein, a facile aqueous solution method is developed to synthesize Bi3+-Yb3+ co-doped Cs2Na0.6Ag0.4InCl6 double perovskite. Besides the intrinsic warm white self-trapped exciton (STE) emission that originated from the Cs2Na0.6Ag0.4InCl6 host, the samples also exhibit a strong near-infrared emission assigned to the 2F5/2 → 2F7/2 transition of octahedral coordinated Yb3+ ions upon excitation with ultraviolet light. The optimized sample shows a markedly high photoluminescence quantum yield of 84.7%. The photophysical studies such as photoluminescence (PL) and photoluminescence excitation spectra, temperature-dependent PL spectra, and PL decay curves reveal that the strong Yb3+ emission is attributed to the energy transfer from STEs to the Yb3+ ions. Finally, the lead-free double perovskite phosphor-converted LED containing visible and NIR regions was fabricated, with 8.92 mW output power at 100 mA drive current. The results show the great potential of the as-prepared crystals in optoelectronics applications.

The tallysomycins (TLMs) belong to the bleomycin (BLM) family of antitumor antibiotics. The BLM biosynthetic gene cluster has been cloned and characterized previously from Streptomyces verticillus ATCC 15003, but engineering BLM biosynthesis for novel analogs has been hampered by the lack of a genetic system for S. verticillus. We now report the cloning and sequencing of the TLM biosynthetic gene cluster from Streptoalloteichus hindustanus E465-94 ATCC 31158 and the development of a genetic system for S. hindustanus, demonstrating the feasibility to manipulate TLM biosynthesis in S. hindustanus by gene inactivation and mutant complementation. Sequence analysis of the cloned 80.2 kb region revealed 40 open reading frames (ORFs), 30 of which were assigned to the TLM biosynthetic gene cluster. The TLM gene cluster consists of nonribosomal peptide synthetase (NRPS) genes encoding nine NRPS modules, a polyketide synthase (PKS) gene encoding one PKS module, genes encoding seven enzymes for deoxysugar biosynthesis and attachment, as well as genes encoding other biosynthesis, resistance, and regulatory proteins. The involvement of the cloned gene cluster in TLM biosynthesis was confirmed by inactivating the tlmE glycosyltransferase gene to generate a TLM non-producing mutant and by restoring TLM production to the DeltatlmE::ermE mutant strain upon expressing a functional copy of tlmE. The TLM gene cluster is highly homologous to the BLM cluster, with 25 of the 30 ORFs identified within the two clusters exhibiting striking similarities. The structural similarities and differences between TLM and BLM were reflected remarkably well by the genes and their organization in their respective biosynthetic gene clusters.