A CuCo Bimetal Confined Hollow SiC Hybrid Photothermal Nanoreactor for the Integration of Pollutant Mineralization and Solar-Powered Water Evaporation.

Growing attention has been paid to the rational treatment of antibiotics-bearing medical wastewater. However, the complexity of polluted wastewater makes the later comprehensive treatment difficult only by the Advanced Oxidation Process technique. Therefore, the coupled water treatment techniques including contaminant mineralization and regeneration of cleanwater become very attractive. A bimetallic functional hollow nanoreactor defined as (Co@SiO2/Cu-X) was successfully constructed by coating a Cu-doped silica layer on the metal-organic framework (ZIF-67) followed by programmed calcination in nitrogen. The nanoreactor was endowed with a hollow configuration composed of mesoporous N-doping C-Silica hybrid shell encapsulated ultrafine Cu and Co metallic species. Such a configuration allows for the efficient diffusion and open reaction space of big contaminant molecules. The catalytic synergy of exposed Co-Cu bimetals and the easy accessibility of electron-rich contaminants by polar N doping sites triggered surface affinity make the optimal Co@SiO2/Cu-6 afford an excellent catalytic norfloxacin mineralization activity (7 min, kabs=0.744 min-1) compared to Cu-free Co@SiO2-6 (kabs=0.493 min-1) and Co-6 (kabs=0.378 min-1) Benefiting from the above unique advantages, Co@SiO2/Cu-6 show excellent removal performance in degrading different pollutants (carbamazepine, oxytetracycline, tetracycline, and bisphenol A) and persistent recycled stability in removing NFX. In addition, by virtue of the excellent photothermal properties, interfacial solar water evaporation application by Co@SiO2/Cu-6 was further explored to reach the regeneration of cleanwater (1.595 kg m-2 h-1, 97.51 %). The integration of pollutant mineralization and solar water evaporation by creating the monolith evaporation by anchoring the Co@SiO2/Cu-6 onto the tailored melamine sponge allows the regeneration of cleanwater (1.6 kg⋅m-2⋅h-1) and synchronous pollutant removal (NFX, 95 %, 60 min), which provides potential possibility the treatment of complicated wastewater.

[Effect and mechanism of Puerariae Lobatae Radix in alleviating insulin resistance in T2DM db/db mice based on intestinal flora].

This study aimed to examine the effect and underlying mechanism of Puerariae Lobatae Radix on insulin resistance in db/db mice with type 2 diabetes mellitus(T2DM) based on the analysis of intestinal flora. Fifty db/db mice were randomly divided into a model group(M group), a metformin group(YX group), a high-dose Puerariae Lobatae Radix group(YGG group), a medium-dose Puerariae Lobatae Radix group(YGZ group), and a low-dose Puerariae Lobatae Radix group(YGD group). Another 10 db/m mice were assigned to the normal group(K group). After continuous administration for eight weeks, body weight and blood sugar of mice were measured. Enzyme linked immunosorbent assay(ELISA) was used to detect glycosylated serum protein(GSP) and fasting serum insulin(FINS), and insulin resistance index(HOMA-IR) was calculated. The histopathological changes in the pancreas were observed by HE staining. Tumor necrosis factor(TNF)-α expression in the pancreas was detected using immunohistochemistry. The structural changes in fecal intestinal flora in the K, M, and YGZ groups were detected by 16S rRNA. Western blot was used to detect the expression of farnesoid X receptor(FXR) and takeda G protein-coupled receptor 5(TGR5) in the ileum, cholesterol 7α-hydroxylase(CYP7A1) and sterol 27α-hydroxylase(CYP27A1) in the liver, and G protein-coupled receptors 41(GPR41) and 43(GPR43) in the colon. Compared with the K group, the M group showed increased body weight, blood sugar, serum GSP, fasting blood glucose(FBG), and FINS, increased HOMA-IR, inflammatory infiltration of islet cells, necrosis and degeneration of massive acinar cells, unclear boundary between islet cells and acinar cells, disturbed intestinal flora, and down-regulated FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43. Compared with the M group, the YX, YGG, YGZ, and YGD groups showed decreased body weight, blood sugar, serum GSP, FBG, and FINS, islet cells with intact and clumpy morphology and clear boundary, necrosis of a few acinar cells, and more visible islet cells. The intestinal flora in the YGZ group changed from phylum to genus levels, and the relative abundance of intestinal flora affecting the metabolites of intestinal flora increased. The protein expression of FXR, TGR5, CYP7A1, CYP27A1, GPR41, and GPR43 increased. The results show that Puerariae Lobatae Radix can improve the inflammatory damage of pancreatic islet cells and reduce insulin resistance in db/db mice with T2DM. The mechanism of action may be related to the increase in the abundance of Actinobacteria, Bifidobacterium, and Bacteroides in the intestinal tract and the protein expression related to metabolites of intestinal flora.

Risk-Sensitive Markov Decision Processes of USV Trajectory Planning with Time-Limited Budget.

Trajectory planning plays a crucial role in ensuring the safe navigation of ships, as it involves complex decision making influenced by various factors. This paper presents a heuristic algorithm, named the Markov decision process Heuristic Algorithm (MHA), for time-optimized avoidance of Unmanned Surface Vehicles (USVs) based on a Risk-Sensitive Markov decision process model. The proposed method utilizes the Risk-Sensitive Markov decision process model to generate a set of states within the USV collision avoidance search space. These states are determined based on the reachable locations and directions considering the time cost associated with the set of actions. By incorporating an enhanced reward function and a constraint time-dependent cost function, the USV can effectively plan practical motion paths that align with its actual time constraints. Experimental results demonstrate that the MHA algorithm enables decision makers to evaluate the trade-off between the budget and the probability of achieving the goal within the given budget. Moreover, the local stochastic optimization criterion assists the agent in selecting collision avoidance paths without significantly increasing the risk of collision.

Theoretical Understanding on the Facilitated Photoisomerization of a Carbonyl Supported Borane System.

Boron compound BOMes2 containing an internal B-O bond undergoes highly efficient photoisomerization, followed by sequential structural transformations, resulting in a rare eight-membered B, O-heterocycle (S. Wang, et al. Org. Lett. 2019, 21, 5285-5289). In this work, the detailed reaction mechanisms of such a unique carbonyl-supported tetracoordinate boron system in the first excited singlet (S1 ) state and the ground (S0 ) state were investigated by using the complete active space self-consistent field and its second-order perturbation (MS-CASPT2//CASSCF) method combined with time-dependent density functional theory (TD-DFT). Moreover, an imine-substituted tetracoordinated organic boron system (BNMes2 ) was selected for comparative study to explore the intrinsic reasons for the difference in reactivity between the two types of compounds. Steric factor was found to influence the photoisomerization activity of BNMes2 and BOMes2 . These results rationalize the experimental observations and can provide helpful insights into understanding the excited-state dynamics of heteroatom-doped tetracoordinate organoboron compounds, which facilitates the rational design of boron-based materials with superior photoresponsive performances.

Optimized Dynamic Collision Avoidance Algorithm for USV Path Planning.

Ship collision avoidance is a complex process that is influenced by numerous factors. In this study, we propose a novel method called the Optimal Collision Avoidance Point (OCAP) for unmanned surface vehicles (USVs) to determine when to take appropriate actions to avoid collisions. The approach combines a model that accounts for the two degrees of freedom in USV dynamics with a velocity obstacle method for obstacle detection and avoidance. The method calculates the change in the USV's navigation state based on the critical condition of collision avoidance. First, the coordinates of the optimal collision avoidance point in the current ship encounter state are calculated based on the relative velocities and kinematic parameters of the USV and obstacles. Then, the increments of the vessel's linear velocity and heading angle that can reach the optimal collision avoidance point are set as a constraint for dynamic window sampling. Finally, the algorithm evaluates the probabilities of collision hazards for trajectories that satisfy the critical condition and uses the resulting collision avoidance probability value as a criterion for course assessment. The resulting collision avoidance algorithm is optimized for USV maneuverability and is capable of handling multiple moving obstacles in real-time. Experimental results show that the OCAP algorithm has higher and more robust path-finding efficiency than the other two algorithms when the dynamic obstacle density is higher.

Modulating photothermal properties by integration of fined Fe-Co in confined carbon layer of SiO2 nanosphere for pollutant degradation and solar water evaporation.

Environmental governance by photothermal materials especially for the separation of organic pollutants and regeneration of freshwater afford growing attention owing to their special solar-to-heat properties. Here, we construct a special functional nanosphere composed of an internal silica core coated by a thin carbon layer encapsulated plasmonic bimetallic FeCo2O4 spinel (SiO2@CoFe/C) by a facile self-assembled approach and tuned calcination. Through combining the advantage of bimetallic Fe-Co and carbon layer, this obtained nanosphere affords improved multiple environmental governing functions including peroxymonosulfate (PMS) activation to degrade pollutants and photothermal interfacial solar water evaporation. Impressively, fined bimetal (FeCo) species (20 nm) acted as main catalytic substance were distributed on the N-doping carbon thin layer, which favors electron transfer and reactive accessibility of active metals. The increasing treatment temperature of catalysts caused the optimization of the surface active metal species and tuning catalytic properties in the AOPs. Besides, the incorporation of Co in the SiO2@CoFe/C-700 could enable the improved PMS activation efficiency compared to SiO2@Fe/C-700 and the mixed SiO2@Co/C-700 and SiO2@Fe/C-700, hinting a synergetic promotion effect. The bimetal coupled catalyst SiO2@CoFe/C-700 affords enhanced photothermal properties compared to SiO2@Co/C-700. Furthermore, photothermal catalytic PMS activation using optimal SiO2@CoFe/C-700 was further explored in addressing stubborn pollutants including oxytetracycline, sulfamethoxazole, 2, 4-dichlorophenol, and phenol. The free radical quenching control suggests that both the sulfate radical, hydroxyl radical, superoxide radical, and singlet oxygen species are involved in the degradation, while the hydroxyl radical and singlet oxygen play a dominant role. Furthermore, the implementation of a solar-driven interfacial water evaporation model using SiO2@CoFe/C-700 was further studied to obtain freshwater regeneration (1.26 kg m-2 h-1, 76.81% efficiency), indicating the comprehensive ability of the constructed nanocomposites for treating complicated environmental pollution including organics removal and freshwater regeneration.

[Mechanism of Shenling Baizhu Powder on treatment of ulcerative colitis based on NLRP3 inflammatory].

This study deciphered the mechanism of Shenling Baizhu Powder in treatment of mouse model of ulcerative colitis(UC) via NOD-like receptor thermoprotein domain 3(NLRP3) signaling pathway. After three days of adaptive feeding, 70 SPF-grade BALB/c mice were randomized into 7 groups: normal group, model group(dextran sodium sulfate, DSS), mesalazine group(DSS + 5-aminosalicylic acid, 5-ASA), NLRP3 inhibitor group(DSS + MCC950), and high-, medium-, and low-dose Shenling Baizhu Powder groups(DSS + high-, medium-, and low-dose Shenling Baizhu Powder), with 10 mice per group. The normal group had free access to double distilled water, and the remaining groups had free access to DSS-containing water to establish the acute UC model. Intragastric administration was started at the same time as modeling for one week. During the experiment, the general mental state and disease activity of each group of mice were recorded and scored. After the experiment, colon and serum samples were collected. The pathological changes in colon tissue were observed through hematoxylin-eosin(HE) staining. Enzyme-linked immunosorbent assay(ELISA) was employed to determine the levels of interleukin-18(IL-18) and myeloperoxidase(MPO) in colon tissue and interleukin-1ß(IL-1ß) in serum. Immunofluorescence(IF) and immunohistochemistry(IHC) methods were employed to examine the expression of NLRP3 and IL-18 in colon tissue. Western blot was employed to measure the protein levels of NLRP3, apoptosis-associated speck-like protein(ASC), cystein-aspartate protease 1(caspase-1), and downstream inflammatory cytokines in colon tissue. Compared with the normal group, the modeling of UC increased the disease activity index(DAI), colon pathological injury score, IL-1ß level in serum, and IL-18 and MPO levels in colon tissue(P<0.05, P<0.01). Furthermore, the modeling caused obvious pathological changes and up-regulated the expression of NLRP3, caspase-1, ASC, pro-IL-1ß, cleaved-IL-1ß, pro-IL-18, and cleaved-IL-18 in the colon(P<0.01). Compared with the model group, the administration of corresponding drugs decreased the DAI, pathological injury score, IL-1ß level in serum, and IL-18 and MPO levels in colon tissue, and down-regulated the protein levels of NLRP3, caspase-1, ASC, pro-IL-1ß, cleaved-IL-1ß, pro-IL-18, and cleaved-IL-18 in the colon(P<0.05, P<0.01). According to the results of previous study and this study, we concluded that Shenling Baizhu Powder can alleviate the inflammatory response and intestinal damage of DSS-induced UC by regulating the expression of the proteins and inflammatory cytokines associated with NLRP3 signaling pathway.

Understanding of Photo-Induced Reversible Rearrangement from Borepin to Borirane.

The first reversible photoisomerization between a borepin and a borirane was reported in the photo-induced reactions of B(npy)Ar2 (npy=2-(naphthalen-1-yl) pyridine, Ar=phenyl or electron rich aryl; S. Wang, et al. Angew. Chem. Int. Ed. 2019, 58, 6683-6687). In this work, the detailed mechanisms of the unprecedented reversible photoisomerization between the borepin (compound a) and the borirane (compound b) of B(npy)Ph2 in the first excited singlet (S1 ) state and the ground (S0 ) state were studied by carrying out calculations with the complete active space self-consistent field (CASSCF) and its second-order perturbation (CASPT2) methods combined with time-dependent density functional theory (TD-DFT). The calculation results show that photoexcitation of a-S0 at 365 nm and b-S0 at 450 nm populate their S1 state with evident charge transfer characteristics. The photoisomerization is triggered in the S1 state and ends in the S0 state, at which the intersection points in a (S1 /S0 )x intersection seam participate in and promote phenyl migration and ring-closure processes. Furthermore, we reveal that the not large energy difference (less than 0.6 eV) and similar conjugation properties of π electrons between a-S0 and b-S0 are responsible for their unique photo-reversible reactivity, compared with those of the isomers of the thermally reversible compound B(ppy)Mes2 . Our results contribute to an understanding of the excited-state reactivity of organoboron compounds and will be useful to support the design of new boron-based photo-responsive materials.

Ultra Narrow Dual-Band Perfect Absorber Based on a Dielectric-Dielectric-Metal Three-Layer Film Material.

This paper proposes a perfect metamaterial absorber based on a dielectric-dielectric-metal structure, which realizes ultra-narrowband dual-band absorption in the near-infrared band. The maximum Q factor is 484. The physical mechanism that causes resonance is hybrid coupling between magnetic polaritons resonance and plasmon resonance. At the same time, the research results show that the intensity of magnetic polaritons resonance is much greater than the intensity of the plasmon resonance. By changing the structural parameters and the incident angle of the light source, it is proven that the absorber is tunable, and the working angle tolerance is 15°. In addition, the sensitivity and figure of merit when used as a refractive index sensor are also analyzed. This design provides a new idea for the design of high-Q optical devices, which can be applied to photon detection, spectral sensing, and other high-Q multispectral fields.

Erbium Single Atom Composite Photocatalysts for Reduction of CO2 under Visible Light: CO2 Molecular Activation and 4f Levels as an Electron Transport Bridge.

It is still challenging to design a stable and efficient catalyst for visible-light CO2 reduction. Here, Er3+ single atom composite photocatalysts are successfully constructed based on both the special role of Er3+ and the special advantages of Zn2 GeO4 /g-C3 N4 heterojunction in the photocatalysis reduction of CO2 . Especially, Zn2 GeO4 :Er3+ /g-C3 N4 obtained by in situ synthesis is not only more conducive to the tight junction of Zn2 GeO4 and g-C3 N4 , but also more favorable for g-C3 N4 to anchor rare-earth atoms. Under visible-light irradiation, Zn2 GeO4 :Er3+ /g-C3 N4 shows more than five times enhancement in the catalytic efficiency compared to that of pure g-C3 N4 without any sacrificial agent in the photocatalytic reaction system. A series of theoretical and experimental results show that the charge density around Er, Ge, Zn, and O increases compared with Zn2 GeO4 :Er3+ , while the charge density around C decreases compared with g-C3 N4 . These results show that an efficient way of electron transfer is provided to promote charge separation, and the dual functions of CO2 molecular activation of Er3+ single atom and 4f levels as electron transport bridge are fully exploited. The pattern of combining single-atom catalysis and heterojunction opens up new methods for enhancing photocatalytic activity.

Stable nitrogen-rich scandium nitrides and their bonding features under ambient conditions.

All-nitrogen salts have attracted extensive attention because of their unique chemical, physical properties, and potential applications as high-energy density materials. Using first-principles calculations and a particle swarm optimization structure search method, the pressure versus composition phase diagram of the Sc-N system is established. A new stable phase of C2/m-ScN5 with the intriguing 2D N106- is identified for the first time and we also found ScN3 with the P1[combining macron] structure which has been reported before. Under ambient conditions, both of them have high kinetic and thermodynamic stability with high energy density (2.40 kJ g-1 and 4.23 kJ g-1 relative to ScN and N2 gas). The analyses of chemical bonding pattern indicate that the nitrogen atoms in the N66- chains are connected by covalent bonds with a combined σ and π bond character. We also give a possible high-pressure experimental route to P1[combining macron]-ScN3 and C2/m-ScN5 at modest pressure. We expect that our theoretical research could encourage experimental realization in the future and contribute to the understanding of the bonding features of nitrogen chains.

Transformation of Ammonium Azide at High Pressure and Temperature.

The compression of ammonium azide (AA) has been considered to be a promising route for producing high energy-density polynitrogen compounds. So far though, there is no experimental evidence that pure AA can be transformed into polynitrogen materials under high pressure at room temperature. We report here on high pressure (P) and temperature (T) experiments on AA embedded in N2 and on pure AA in the range 0-30 GPa, 300-700 K. The decomposition of AA into N2 and NH3 was observed in liquid N2 around 15 GPa-700 K. For pressures above 20 GPa, our results show that AA in N2 transforms into a new crystalline compound and solid ammonia when heated above 620 K. This compound is stable at room temperature and on decompression down to at least 7.0 GPa. Pure AA also transforms into a new compound at similar P-T conditions, but the product is different. The newly observed phases are studied by Raman spectroscopy and X-ray diffraction and compared to nitrogen and hydronitrogen compounds that have been predicted in the literature. While there is no exact match with any of them, similar vibrational features are found between the product that was obtained in AA + N2 with a polymeric compound of N9H formula.

Insights into the Photoinduced Isomerization Mechanisms of a N,C-Chelate Organoboron Compound: A Theoretical Study.

As the first discovered organoboron compound with photochromic property, B(ppy)Mes2 (ppy=2-phenylpyridine, Mes=mesityl) displays rich photochemistry that constitutes a solid foundation for wide applications in optoelectronic fields. In this work, we investigated the B(ppy)Mes2 to borirane isomerization mechanisms in the three lowest electronic states (S0 , S1 , and T1 ) based on the complete active space self-consistent field (CASSCF) and its second-order perturbation (CASPT2) methods combined with time-dependent density functional theory (TD-DFT) calculations. Our results show that the photoisomerization in the S1 state is dominant, which is initiated by the cleavage of the B-Cppy bond. After overcoming a barrier of 0.5 eV, the reaction pathway leads to a conical intersection between the S1 and S0 states (S1 /S0 )x , from which the decay path may go back to the reactant B(ppy)Mes2 via a closed-shell intermediate (Int1-S0 ) or to the product borirane via a biradical intermediate (Int2-S0 ). Although triplet states are probably involved in the photoinduced process, the possibility of the photoisomerization in T1 state is very small owing to the weakly allowed S1 →T1 intersystem crossing and the high energy barrier (0.77 eV). In addition, we found the photoisomerization is thermally reversible, which is consistent with the experimental observations.

H2S detection at low temperatures by Cu2O/Fe2O3 heterostructure ordered array sensors.

2D heterostructures are promising gas sensor materials due to their surface/interface effects and hybrid properties. In this research, Cu2O/Fe2O3 heterostructure ordered arrays were synthesized using an in situ electrodeposition method for H2S detection at low temperatures. These arrays possess a periodic long range ordered structure with horizontal multi-heterointerfaces, leading to superior gas sensitivity for synergistic effects at the heterointerfaces. The sensor based on the Cu2O/Fe2O3 heterostructure ordered arrays exhibits a dramatic improvement in H2S detection at low temperatures (even as low as -15 °C). The response is particularly significant at room and human body temperatures since the conductivity of the arrays can change by up to three orders of magnitude in a 10 ppm H2S atmosphere. These good performances are also attributed to the formation of metallic Cu2S conducting channels. Our results imply that the Cu2O/Fe2O3 heterostructure ordered arrays are promising candidates for high-performance H2S gas sensors that function at low temperatures as well as breath analysis systems for disease diagnosis.

Synthesis and high-pressure studies of strontium diazenide by synchrotron X-ray diffraction and DFT calculations.

In this work, strontium diazenide (SrN2) was synthesized using strontium azide as a starting material in a Walker-type module under high-pressure and high-temperature conditions. The synthesized SrN2 was further studied under high pressure up to 43.2 GPa using in situ synchrotron X-ray diffraction to supplement the high-pressure exploration of alkaline earth diazenides. The SrN2 underwent a possible phase transition from a tetragonal structure into an orthorhombic structure at 12.0 GPa. SrN2 shows anisotropic compressibility due to the orientation of the diazenide anions. The bulk modulus of SrN2 is 132.4 (10.2) GPa, which is larger than that of Sr(N3)2. The larger bulk modulus of SrN2 is attributed to the stronger covalent strength between Sr and N atoms in SrN2, which is confirmed by our theoretical calculations.

Zn-Alloyed All-Inorganic Halide Perovskite-Based White Light-Emitting Diodes with Superior Color Quality.

Recently, lead halide perovskite nanocrystals (NCs) have gained tremendous attention in optoelectronic devices due to their excellent optical properties. However, the toxicity of lead limits their practical applications. Here, the synthesis of Zn2+-alloyed CsZnxPb1-xX3 (up to 15%) NCs is reported to achieve lead-reduced white light-emitting diodes (WLEDs). The incorporation of Zn2+ into CsPbX3 host NCs results in a lattice contraction, without altering the structure and morphology, which has a direct effect on the optical properties. The blue-shifts in the photoluminescence emission and increase in bandgap is observed while retaining high photoluminescence quantum yield. Then by engineering the different compositions of halides for 15% Zn2+-alloyed CsZnxPb1-xX3 NCs, tunable emission (411-636 nm) is obtained. Notably, the WLEDs are experimentally demonstrated employing the lead-reduced NCs (blue, green, yellow, and red). By varying the ratios of the amount of NCs, white lights with a tunable correlated-color temperature (2218-8335 K), an exemplary color-rendering index (up to 93) and high luminous efficacy of radiation (268-318 lm·W-1) are obtained. Best of our knowledge, these are superior to other reported WLEDs based on CsPbX3 NCs doped with transition metal ions. This work places the halide perovskite NCs one-step closer in designing the environmentally benign and energy-efficient WLEDs.

Design rules for white light emitters with high light extraction efficiency.

The finite-difference time-domain method is employed to study the light extraction efficiency of white light emitters. The cone arrays designed on top of white light emitters eliminate the dependency of light extraction on the wavelength and the cavity thickness and that leads to significant enhancement in light extraction efficiency for whole visible light spectrum. The light extraction efficiency of 81% has been achieved. Most importantly, the high extraction efficiency is achieved for the whole visible spectrum from 400 nm to 700 nm. This work will provide guidelines for designing highly efficient white light emitters for general illumination and display purpose.

Theoretical study on the regioselective photoisomerization of asymmetric N,C-chelate organoboron compounds.

Herein, the complete active space self-consistent field (CASSCF) and its second-order perturbation (CASPT2) methods combined with time-dependent density functional theory (TD-DFT) calculations were employed to investigate the isomerization reaction mechanisms of an asymmetric N,C-chelate organoboron compound, B(ppy)MesPh, in the ground (S0) state and the first singlet excited (S1) state. Our calculations show that isomerizations proceed via different pathways in the S0 and S1 states,; however, the energy barriers for mesityl isomerization are higher than those for phenyl isomerization in both states; this is in good agreement with the experimentally observed regioselectivity (S. Wang, et al. Angew. Chem., Int. Ed., 2017, 56, 6093-6097). Photoisomerization is motivated by charge transfer from two phenyl rings to the pyridyl moiety and initiated by the cleavage of the B-Cppy bond, followed by the formation of a boracyclopropane ring via an (S1/S0)X conical intersection and a biradical intermediate. Both steric and electronic features were found to be important for regioselective photoisomerization. Our results not only shed light on the experimental observations, but also provide valuable details on the excited state dynamics of organoboron compounds and can facilitate further syntheses and applications.

Tetradic phosphor white light with variable CCT and superlative CRI through organolead halide perovskite nanocrystals.

In this work, the emission spectral range of halide perovskite nanocrystals is extended from violet to infrared, the widest emission range for halide perovskites to date. This range extension was made possible by a cost-effective solution-based synthesis process that only involves two halides [MAPb(Br x I1-x )3 and MA = CH3NH3]. Furthermore, the correlated-color temperature (CCT) of white light is tuned by blending an appropriate fraction of the as-synthesized blue, green, yellow, and red emitting nanocrystals. This represents one of the first applications of a tetradic phosphor system for maximizing the color rendering index (CRI) for this material. The CCT ranges from warm to cool white (2759-6398 K) and the CRI has a maximum value of 93.95. Thus, this fourfold phosphor approach demonstrates that halide perovskites are promising alternatives to conventional phosphors in the search for low-cost and high-quality white light sources in the next generation of white lighting technology.

Pressure induced photoluminescence modulation in a wide range and synthesis of monodispersed ternary AgCuS nanocrystal based on Ag2S nanocrystals.

Binary Ag2S nanocrystals (NCs) have many potential optical applications because of their low toxicity, narrow direct band gaps and near-infrared photoluminescence (PL) with high emission efficiency. However, due to its small exciton Bohr radius (2.2 nm), the PL spectra of Ag2S NCs can only be modulated below ∼1200 nm with increasing particle size. Meanwhile, ternary silver copper chalcogenides (AgCuX, X = S, Se) have also attracted increased attention in recent years. Temperature-dependent structural phase transformation leads electrical transport to exhibit fascinating transitions between p and n type conduction, which makes AgCuS and AgCuSe ideal materials for diode or transistor devices. Nevertheless, the traditional method to synthesize these materials is mainly through melting the mixture of Ag, Cu and S/Se powder under extremely high reaction temperatures (973-1373 K) and long reaction time, forming a bulk product. Therefore, the synthesis of high quality monodispersed and size-tunable AgCuS or AgCuSe NCs is still a challenge. To address these issues, in this paper, we report using Ag2S NCs as a template, a method to synthesize monodispersed and size-tunable ß-AgCuS NCs via ion exchange and diffusion processes. Similarly, monodispersed ß-AgCuSe NCs were also synthesized by this simple and reproducible strategy. This synthetic method opens new avenues for investigating the size-, morphology- and temperature-dependent phase transitions of these ternary AgCuS and AgCuSe materials. Thus, the corresponding electrical transport between p and n type conduction can be studied in the future. Furthermore, we systematically investigated the pressure-dependent PL properties and band gap modulation of monodispersed Ag2S NCs using in situ high pressure PL and absorption spectroscopy. We found that the PL peak of 6.0 nm for Ag2S NCs could be easily adjusted from ∼1200 to 1900 nm with increasing pressure from 0 to 5.1 GPa, which greatly extends the wavelength range of the PL peak beyond that of other approaches.