Developing pure organic room-temperature phosphorescence (RTP) materials remains an enormous challenge, especially for efficient near-infrared (NIR) RTP materials. Herein, a functional unit combination strategy is employed to design a series of pure organic molecules, in which benzo[c][1,2,5]thiadiazole (BZT) serves as the main luminescent core of RTP, while the folded units are responsible for spin-orbit coupling (SOC) enhancement and emission redshift. By integrating both rigid and flexible folded units into the BZT core, we observe the n/pi orbital decoupling between the folded units and the BZT core. This orbital decoupling facilitates significant interplay between orbital angular momentum and heavy-atom effect, maximizing the SOC. As a result, a molecule functionalized with thianthrene and phenyl selenide demonstrates efficient NIR RTP emission, which exhibits a maximum RTP wavelength at 705 nm and a high RTP efficiency of 10.25%, surpassing most of the reported pure organic NIR RTP materials. As an emitter, its doped organic light-emitting diode (OLED) device demonstrates excellent NIR electroluminescence with a maximum external quantum efficiency of 1.21%. To our knowledge, this work not only reports the first example of pure organic NIR phosphorescent OLED, but also reveals a n/pi orbital decoupling strategy for designing highly efficient pure organic RTP materials.

Blue emitters are crucial in the organic light emitting diode (OLED) industry and scientific field. In this work, we prepared a novel donor-π-acceptor (D-π-A) molecular PCZ-P-PY using pyrene as a bridge to construct hybrid local and charge-transfer (HLCT) state with weak charge-transfer (CT) property. This excited state design give rise to the high photoluminescent quantum yield (PLQY), more importantly, it is also responsible for the high exciton utilization efficiency (EUE) by constructing efficient hot-exciton channel. As a result, exceeding external quantum efficiency (EQE) of 5.7 % is achieved in the non-doped OLED of PCZ-P-PY with exceeding EUE of up to 90 %.

Manipulation of the oxidation degree of sulfur is carried out to synthesize sulfide-, sulfoxide- and sulfone-substituted pyrenes, fine-tune the electronic effect and stiffness of the molecules, and obtain optimal luminous efficiency of the excimers.

Rational regulation on the hybrid local and charge-transfer (HLCT) excited state is crucial for the optimization of light color, especially those of the blue-emissive materials. In this work, two rigid, orthogonal donor-acceptor (D-A) materials are designed and synthesized using the tripenylamine-phenanthroimidazole backbone donor and triphenyltriazine as the acceptor, with different distance between the donor and acceptor units. The shorter distanced DRZ-TPM forms a typical CT excited state, and its organic light emitting diode (OLED) produced green electroluminescence with maximum external quantum efficiency (EQEmax) of 5.0%. To regulate the light color, we inserted a phenyl ring to increase the donor-acceptor distance for a reduced CT component. The new material TRZ-TPM achieves sky-blue electroluminescence at 452 nm with EQEmax of 2.5% in doped OLED. Furthermore, TRZ-TPM showed obvious excimer emission in the aggregated state, and the non-doped OLED performed reduced opening-voltage comparing to the doped OLED, owing to the better formation of intermolecular charge-transfer state.

Rechargeable lithium-sulfur battery is considered to be one of the most promising candidates for the next-generation energy storage applications due to its high energy density, large theoretical specific capacity, low cost, and abundant sources. However, low conductivity of sulfur, shuttle effect, and volume expansion hindered its practical application. In this study, N,P co-doped hierarchical porous carbon has been fabricated from biomass fallen leaves through novel simple carbonization process with mild H 3 PO 4 as an activator. By adjusting the mass ratio of H 3 PO 4 and leaves, the porous carbon can be optimized to be tube-like morphology with a neatly arranged or monodispersed layout way. When serving as a sulfur host, the as-produced N,P dual-heteroatom doped porous carbon is favorable for advanced conductivity and binding polysulfides through physi-/chemisorption, so as to endow excellent electrochemical performance. An initial specific capacity of 1320 mAh·g −1 can be achieved and maintained above 1000 mAh·g −1 after 300 cycles at 0.1C.

In this work, two novel D-π-A compounds (PXZ-FR-DRZ and CZ-FR-DRZ) are designed and synthesized, aiming at the excited-state regulation from thermally-activated delayed fluorescence (TADF) to hybridized local and charge-transfer (HLCT) emission. This change of excited-state nature can be ascribed to the weakened electron-donating ability of carbazole relative to phenoxazine, together with the decreased twisting angle between carbazole and fluorine units. As a result of twisted charge-transfer (CT) excited state, the doped organic light-emitting diode (OLED) of PXZ-FR-DRZ demonstrates a blue-green TADF electroluminescence (EL) with a maximum external quantum efficiency (EQEmax) of 11.5%, while its non-doped device shows a much lower EQEmax. Due to HLCT state of CZ-FR-DRZ, both its doped and non-doped OLEDs achieve the deep-blue non-delayed EL with the satisfied external quantum efficiency (EQE), especially for the excellent efficiency roll-off. Overall, this excited-state transformation between TADF and HLCT allows us to harvest the better comprehensive performance of OLED emitters for the practical applications, which provides a feasible solution for the development of OLED industry.

This work not only gives a new functional group for the construction of deep-red pure organic efficient excimer materials, but also further verifies that the “hot exciton” theory can also be effective in excimer-based OLEDs.

Ag/Co/B tri-doped TiO2/SiO2 film was prepared by the sol–gel method, and the structure and properties of this film were characterized by the X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) test method, field emission scanning electron microscopy (FE-SEM), differential thermal analysis-thermogravimetry (DTA-TG), photoluminescence (PL), and UV-visible diffuse reflectance spectrum (UV-vis DRS). XRD results indicated that the film structure of this film conforms to the anatase single crystal form. The presence of SiO2 can inhibit the formation of brookite and prevent the conversion of anatase into rutile. BET and FE-SEM results revealed that the film had a higher specific surface area and smaller grain size compared with pure TiO2 film. DTA-TG results exposed that the film had excellent thermal stability at 450[Formula: see text]C. Due to the spectacular adsorption capacity of SiO2 and the Schottky barrier formed between Ag and TiO2, this film improved the h[Formula: see text]/e[Formula: see text] separation efficiency and optical absorption performance showed by PL results. UV-vis DRS results displayed that the band gap energy (2.47 eV) of the film was clearly lower than that of pure TiO2 film, due to the intermediate energy levels generated by Co and B ions doping. The photocatalytic activity of the film was verified by ultraviolet and visible light degradation experiments of two different organic pollutants. The experimental results exhibited that the film had excellent photocatalytic degradation ability and stability. Ultimately, a possible synergistic mechanism of photocatalysis was proposed in this paper.

Lead halide perovskites have gained extensive attention in the photodetectors (PDs) field, but the problems of intrinsic toxicity and poor stability still hamper their practical applications. Furthermore, ultraviolet (UV) PDs have rarely been explored due to challenges, including the lack of suitable materials and the costly and complicated fabrication processes. In order to solve the above problems, herein it is reported a novel all‐inorganic lead‐free halide CsAg2I3 single crystal (SC) with pure phase and high quality. This CsAg2I3 SC shows ultra‐stable crystal structure, steady chemical properties, and good optical properties, and it can be stable up to 893 K. Its 1D crystal structure and soft crystal lattice support the formation of self‐trapped excitons, leading to a broadband emission at 610 nm with a large Stokes shift of 315 nm (2.23 eV). The strong absorption for UV light combined with direct bandgap, large Stokes shift, and ultra‐high stability promises an environment‐friendly, low‐cost, and high‐performance UV PD based on the 1D all‐inorganic silver (I) halides.

The abuse of antibiotics such as malachite green (MG) has caused its residues in foods and environmental water, and therefore, it is important to establish a rapid and reliable method for sensitive detection of antibiotics. In this work, a novel molecularly imprinted polymer surface-enhanced Raman spectroscopy (SERS) sensor integrating high sensitivity, selectivity, and reusability is fabricated for the detection of trace MG in environmental water. SiO2@Au, by adjusting the gap between nanoparticles, provides SERS activity, and then the template MG is molecularly imprinted and wrapped by oxidative self-polymerization properties of dopamine (SA-100@MIP). The prepared SA-100@MIP achieved sensitive and selective detection of MG in pond water (0.1 nM) and presented a good linear correlation in the range of 10-6-10-10 M. Moreover, the substrate still has excellent SERS performance after 12 times of repeated use. These properties indicate that this sensor may provide broad prospects for the practical application of SERS in food and environmental monitoring.

Early detection is vital for the prevention and treatment of patients with colorectal cancer (CRC). However, existent methods (such as enzyme immunoassay, chemiluminescent immunoassay and radioimmunoassay) for early detection of CRC are time consuming, costly and complicated multistage processes, limiting their further applications. Here, a novel label-free and ultrasensitive detection method is developed for CRC protein marker NDKA by Cr3+ ions aggregating Au@Ag NPs (ICNPs) via surface-enhanced Raman spectroscopy (SERS) spectra for the first time. The Au@Ag NPs with size-controlled Ag shell thickness (1 nm, 3 nm, 5 nm, 7 nm and 9 nm Ag shells) are prepared as the SERS substrates and its Raman signals are Ag shells thickness-dependent sensitivity to proteins. By using Cr3+ ions as aggregating agents, the aggregating effect between the SERS substrates of Au@Ag ICNPs and protein analyte results in significantly enhanced and reproducible Raman signals owing to formation of lots of hotspots. Using this novel method, several label free proteins, myoglobin (3 fg/mL), human serum albumin (30 fg/mL), lysozyme (30 ng/mL) and cytochrome C (30 ng/mL) were also detected at ultralow concentrations with good reproducibility and high sensitivity, demonstrating the potential applications in the fields of medical therapy and clinical diagnosis. (C) 2021 Elsevier B.V. All rights reserved.

The Y, F, and Ag tridoped TiO2/SnO2 composite nanocrystalline film (YFAg-TS) with prominent pho-tocatalytic performance was prepared by the modified sol-gel method and was characterized by utilizing X-ray diffraction (XRD), differential thermal and thermogravimetric (DTA-TG) analysis, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) method, ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), and photoluminescence (PL). The XRD and DTA-TG results expose that the YFAg-TS catalyst is a mixed phase consisting of anatase, rutile, and chlorargyrite, which is beneficial to improving the photocatalytic performance of TiO2. The SEM, TEM, and BET results disclose that the YFAg-TS film has smaller nanoparticles, higher specific surface area, and narrower pore size compared with pure TiO2 film. The XRD and TEM results exhibit that a part of yttrium can enter the TiO2 lattice to induce lattice distortion. The XPS results confirm the presence of Y3+& nbsp; state in the YFAg-TS sample, and Y3+& nbsp; ions can act as the trapping site of electrons to expedite the separation of electrons and holes. The UV-vis DRS results reveal that the YFAg-TS film has an obvious absorption edge shift and a narrower bandgap (2.70 eV) compared with pure TiO2 film. The PL results show that the YFAg-TS film has the highest photogenerated electrons and holes separation efficiency and charges transfer efficiency among all samples. The photocatalytic activity of the YFAg-TS was assessed by monitoring the degradation of methyl green and formaldehyde solution. The results manifest that the YFAg-TS film has high stability and excellent photocatalytic performance. The possible synergistic photocatalytic mechanism of YFAg-TS films has been discussed in this paper.(c) 2021 Published by Elsevier B.V.& nbsp;

The design of simultaneous detection method has broad prospects for cancer diagnosis and prognosis. Herein, we reported a low cost and sensitive SERS sensing platform for simultaneous p21 mRNA and miRNA-21 detection based on duplex-specific nuclease signal amplification (DSNSA) plus multifunctional Fe3O4@SiO2 magnetic nanoparticles (Fe3O4@SiO2 MNPs). Here, Fe3O4@SiO2 MNPs were used as a separation substrate, and Au@AgNPs served as stable and ultrasensitive SERS nanotags. Firstly, Au@AgNPs and Fe3O4@SiO2 MNPs were attached to both ends of capture probe (CP) by covalent bonds. Under the assistance of the target p21 mRNA and miRNA-21, DNA (CP) of the DNA-RNA heteroduplexes could be specifically degraded by DSN and the SERS nanotags that were released from the surface of Fe3O4@SiO2 MNPs. Meanwhile, the target p21 mRNA and miRNA-21 were released and then involved in the next round of signal reactions. The proposed strategy allowed quantitative detection of p21 mRNA and miRNA-21 and the limit of detection (LOD) was 0.12 fM and 0.17 fM, respectively. This method gives a great potential for multiplex detection of biological molecules.

In order to effectively overcome the inherent defects of TiO2 in practical applications including low quantum efficiency and wide band gap, the B/Co/Fe tridoped TiO2/SiO2 composite films with high photocatalytic properties were prepared by the sol-gel method. The physicochemical properties of catalysts were characterized by XRD, FE-SEM, EDS, DTA-TG, BET, DRS and PL. The results shown that the compositing of SiO2 and doping of B/Co/Fe ions in TiO2 could effectively inhibit the phase transformation of anatase to ruffle and the growing of crystal grains at high annealing temperatures. The compositing of SiO2 could enhance the specific surface area (82.6 increased to 335.8 m(2)/g) of samples and provide more adsorption sites. The doping of B/Co/Fe tridoping could form impurity levels in the band gap of TiO2 to shorten the band gap energy (2.54 ev). And the B/Co/Fe tridoped TiO2/SiO2 films could increase the interfacial transfer rate and decrease recombination rate of electrons and holes. The photocatalytic activities of the B/Co/Fe tridoped TiO2/SiO2 films were evaluated under UV or visible light irradiation with two pollutants as target for photodegradation. The results indicated that the films exhibited more excellent photocatalytic activities compared to pure TiO2. The plausible photocatalytic degradation mechanism had been proposed.

Highly luminescent inks are desirable for various applications such as decorative coating, art painting, and anticounterfeiting, to name a few. However, present inks display low photoluminescent efficiency requiring a strong excitation light to make them glow. Here, we report a highly luminescent ink based on the copper-iodide/1-Propyl-1,4-diazabicyclo[2.2.2]octan-1-ium (Cu4I6(pr-ted)2) hybrid cluster with a quantum efficiency exceeding 98%. Under the interaction between the Cu4I6(pr-ted)2 hybrid cluster and polyvinylpyrrolidone (PVP), the highly luminescent Cu4I6(pr-ted)2/PVP ink can be facilely prepared via the one-pot solution synthesis. The obtained ink exhibits strong green light emission that originates from the efficient phosphorescence of Cu4I6(pr-ted)2 nanocrystals. Attractively, the ink displays high conversion efficiency for the ultraviolet light to bright green light emission due to its wide Stokes shift, implying great potential for anticounterfeiting and luminescent solar concentrator coating.

The exploration of lead-free halide perovskite nanocrystals (NCs) with intriguing optical properties is highly desirable owing to the toxicity and instability of lead halide perovskite NCs. Here, a new kind of uniform lead-free double perovskite Cs2NaBiCl6 NCs are reported as versatile hosts to accommodate ionic dopants for improving optical properties especially the photoluminescence (PL). In contrast to the low deep-blue PL with a quantum yield of only 1.7% of the as-synthesized pristine Cs2NaBiCl6 NCs, the PL of the Cs2NaBiCl6 NCs can be impressively regulated and enhanced via doping Ag+, Mn2+, or Eu3+ ions in the double perovskite lattices. The femtosecond time-resolved transient absorption spectroscopy is adopted to unravel the PL enhancement mechanism of the ion doping in the Cs2NaBiCl6 NCs. For the Ag+-doping, the excitonic absorption energy of the Cs2NaBiCl6 NCs can be tuned from 3.82 to 3.48 eV with the significant improvement of the PL quantum yield (PLQY) from 1.7% to 20%. The Mn2+-doped Cs2NaBiCl6 NCs show broad orange-red emission peak centered at 585 nm with a PLQY of 3%, owing to the T-4(1)->(6)A(1) transition of octahedrally coordinated Mn2+. Eu3+-doped Cs2NaBiCl6 NCs are endowed with strong Eu3+5D0 -> F-7(J) (J = 1, 2) orange-red emission at 591 and 615 nm.

All-inorganic lead halide perovskite nanocrystals (NCs) are potential candidates for fabricating high-performance light-emitting diodes (LEDs) owing to their precisely tunable bandgaps, high photoluminescence (PL) efficiency, and excellent color purities. However, the performance of pure red (630-640 nm) all-inorganic perovskite LEDs is still limited by the halide segregation-induced instability of the electroluminescence (EL) of mixed halide CsPbI3-xBrx NCs. Herein, we report an effective approach to improving the EL stability of pure red all-inorganic CsPbI3-xBrx NC-based LEDs via the passivation of potassium bromide on NCs. By adding potassium oleate to the reaction system, we obtained potassium bromide surface-passivated (KBr-passivated) CsPbI3-xBrx NCs with pure red PL emission and a photoluminescence quantum yield (PLQY) exceeding 90%. We determine that most potassium ions present on the surface of NCs bind with bromide ions and thus demonstrate that potassium bromide surface passivation of NCs can both improve the PL stability and inhibit the halide segregation of NCs. Using KBr-passivated CsPbI3-xBrx NCs as an emitting layer, we fabricated stable and pure red perovskite LEDs with emission at 637 nm, showing a maximum brightness of 2671 cd m-2, maximum external quantum efficiency of 3.55%, and good EL stability. The proposed KBr-passivated NC strategy will open a new avenue for fabricating efficient, stable, and tunable pure color perovskite NC LEDs.

For the sake of improving the photocatalytic performance of TiO2, we prepared the B/Ag/Fe tridoped TiO2 films on common glass and stone substrates by the sol–gel method. In this work, the optical absorption, recombination of photogenerated electrons (e−) and holes (h[Formula: see text]), crystal types, thermal stability, composition, specific surface area and photocatalytic activity of the modified TiO2 films were investigated. The results indicated that B/Ag/Fe tridoping not only enhanced the absorption of visible light by TiO2, but inhibited the recombination of electron–hole (e−/h[Formula: see text]) pairs. The tridoping also promoted the formation of anatase and prevented the transformation of anatase to rutile at high temperature. The composite TiO2 has a large specific surface area, about three times that of pure TiO2. The photocatalytic activity of the TiO2 films were evaluated by methyl green (MG) and formaldehyde degradation. In all samples, the B/Ag/Fe tridoped TiO2 film exhibited the highest degradation rate of MG under both ultraviolet and visible light irradiation. The improvement of photocatalytic performance of TiO2 films is due to the synergistic effect of the B/Ag/Fe tridoping, which enhances the absorption of visible light and prolongs the lifetime of e−/h[Formula: see text] pairs and facilitates transfer of interface charge.

Lead halide perovskite nanocrystals (NCs) exhibit great application potential in optoelectronic devices because of their tunable band gaps and facile colloidal synthesis, but they suffer from serious lead toxicity and instability. It is highly desirable to substitute lead with other elements to acquire nontoxic and environmentally friendly lead-free perovskite NCs for optoelectronic devices. Here, we report a general method for the colloidal synthesis of a series of bismuth/antimony-based halide perovskite NCs with various constituents and optical band gaps from 1.97 to 3.15 eV. In our proposed synthetic system, 1-dodecanol is adopted as the solvent instead of the conventionally used 1-octadecene to realize size controllability of bismuth/antimony-based metal halide perovskite NCs. It is found that 1-dodecanol can act as a surfactant to tightly adsorb on the surface of bismuth/antimony-based halide perovskite NCs, enabling their small sizes (∼2 nm) and high dispersibility. Simultaneously, the band gaps of bismuth/antimony-based halide (A3B2X9, where A = CH3NH3, Cs, or Rb, B = Bi or Sb, and X = Cl, Br, or I) perovskite NCs can be systematically tuned by the atomic substitution of A, B, or X lattice sites. Moreover, to show the optoelectronic application potential of these lead-free halide perovskite NCs, a solar cell based on colloidal Cs3Bi2I9 perovskite NCs is demonstrated. The developed colloidal synthesis of bismuth/antimony-based halide NCs in 1-dodecanol will offer an alternative route to fabricating lead-free halide perovskite optoelectronic devices.

With the desire to realize both high capacity and high voltage, a series of materials xLi(2)MnO(3)center dot(1-x)NaNi1/3Co1/3Mn1/3O2 (0.5 >= x >= 0.2) are designed and prepared, which is inspired by the idea from Li-excess materials (the addition of extra lithium, manganese and charge-compensating oxygen lead to formation of structurally integrated xLi(2)M'nO(3)center dot(1-x)LiMO2, M' = Mn or Ti and M = Mn, Co or Ni typically). The addition of Li2MnO3 is intended to enhance the high voltage operation of sodium ternary system NaNi1/3Co1/3Mn1/3O2. X-ray diffraction patterns show that the materials are prone to form P2-type structure with the increment of Li2MnO3. Rate capability and cycle performance indicate that a more stable structure tends to be distinguishable when the content of Li(2)MnO(3 )exceeds 0.3. It is manifested that the introduction of Li2MnO3 not only plays important role in enhancing interface stability but also prevents from dramatic side reaction with electrolyte during high voltage operation. (C) 2019 Elsevier B.V. All rights reserved.