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The synthesized near infrared molybdenum oxide quantum dots perform excellent red fluorescence imaging performance and photothermal performance, which have 600, 650 and 700 nm three unique peaks excited at 540 nm, with a high quantum yield around 20%. Meanwhile, with 808 nm NIR laser excitation, 10 mg/mL modified Molybdenum oxide quantum dots can increase temperature up to 72.2 °C within 150 s and 77.7 °C within 270 s, respectively.

Catalytic activity and stability, reflected in high conversion, heat sink, and time on stream, are the major concerns of endothermic hydrocarbon fuel cracking. In this work, we synthesized a stable...

Organic semiconductors are functional (macro)molecules with tunable physical properties that can be processed as mechanically flexible films over large areas via printing and other solution-based casting methods. Their unique characteristics make them ideal active components for the fabrication of novel flexible, low-power, ultra-light and high-performance devices such as displays, memories and sensors. Compared with planar field-effect transistors, vertical transistors emerged as a cheap and up-scalable solution for the fabrication of devices with nanoscale-sized active channels. The latter offers access to higher current densities at low operating voltages and thus to transition frequencies higher than planar organic transistors. As a result, the vertical organic transistor (VOT) design represents an ideal platform for applications requiring fast operating speeds with reduced power consumption, such as phototransistors and light-emitting devices. In fact, the future development of inexpensive and wearable smart devices depends on the ability to fabricate devices that can operate at low voltages as fast switching units while keeping size and manufacturing costs as low as possible. In this Perspective, we examine the most enlightening works on the development of multifunctional VOTs reported during the last decade and we discuss the challenges and opportunities to expand these strategies towards the technological implementation of VOTs in the next generation of opto-electronics and photonics technologies.

International audience; Long-lasting luminescence in optoelectronic devices is highly sought after for applications in optical data storage and display technology. While in light-emitting diodes this is achieved by exploiting long-afterglow organic materials as active components, such a strategy has never been pursued in light-emitting transistors, which are still rather unexplored and whose technological potential is yet to be demonstrated. Herein, the fabrication of long-afterglow organic light-emitting transistors (LAOLETs) is reported whose operation relies on an unprecedented strategy based on a photoinduced synaptic effect in an inorganic indium-gallium-zinc-oxide (IGZO) semiconducting channel layer, to power a persistent electroluminescence in organic light-emitting materials. Oxygen vacancies in the IGZO layer, produced by irradiation at λ = 312 nm, free electrons in excess yielding to a channel conductance increase. Due to the slow recombination kinetics of photogenerated electrons to oxygen vacancies in the channel layer, the organic material can be fueled by postsynaptic current and displays a long-lived light-emission (hundreds of seconds) after ceasing UV irradiation. As a proof-of-concept, the LAOLETs are integrated in active-matrix light-emitting arrays operating as visual UV sensors capable of long-lifetime green-light emission in the irradiated regions.

In order to meet the demand of large-scale production of organic solar cells and concept of green chemistry, it is essential to develop environment friendly solvent to fabricate OSCs. In this paper, we utilize thiophene (TH) and diphenyl ether (DPE) as halogen-free processing solvent to optimize performance of OSCs based on PTB7-Th:PC71BM, and we choose chlorobenzene (CB) and 1,8-diiodineoctane (DIO) combination as comparison. For PTB7-Th:PC71BM blend film based on pure TH solvent, the blend film exhibits high photoelectron conversion, efficient exciton separate and charges collection and well developed morphology properties, thus, higher Voc, Jsc and FF were obtained than that of pure CB solvent. Furthermore, excellent photovoltaic performance was achieved with the addition of additive. The PCE of 9.02% from TH:5% DPE system was achieved without any thermal or solvent treatments (the pure TH processed devices PCE is 6.93%), while CB (with 2% DIO) based devices show a lower PCE of 7.41% (the pure CB processed devices PCE is 4.06%). The enhanced photovoltaic performance demonstrates that halogen-free solvent of thiophene provides a new strategy to large-scale fabrication of organic solar cells in future.

A series of Ce0.75Zr0.25O2-Al2O3 samples were prepared by conventional coprecipitation, wet impregnation method and novel deposition precipitation, after the corresponding Pd-only close coupled catalysts were obtained by incipient wet impregnation. Differences in surface properties and catalytic performance were investigated systematically by a wealth of characterizations. XPS, H2-TPR and CO chemisorption revealed that the different preparation methods of Ce0.75Zr0.25O2-Al2O3 led to different intensity of interaction between PdO species and support, thus forming different palladium dispersions. BET, XRD and activity evaluation indicated the catalyst obtained by novel deposition precipitation presented superior textural properties, catalytic performance and thermal stability, due to the strongest interaction proved by H2-TPR, XPS and CO chemisorption, which could retard the sintering of noble metal during the aging process. HRTEM images indicate for the catalysts, PdO species are mainly dispersed and stabilized on the ceria resulting from the lower redox potential of Pd2+/Pd0 (0.95 V) than that of Ce4+/Ce3+ (1.72 V). Consequently, it owned higher surface PdO content and dispersion than the catalysts prepared by coprecipitation and impregnation method, presenting its higher catalytic properties.

The dual-emissive N, S co-doped carbon dots (N, S-CDs) with a long emission wavelength were synthesized via solvothermal method. The N, S-CDs possess relatively high photoluminescence (PL) quantum yield (QY) (35.7%) towards near-infrared fluorescent peak up to 648 nm. With the advanced characterization techniques including X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), etc. It is found that the doped N, S elements play an important role in the formation of high QY CDs. The N, S-CDs exist distinct pH-sensitive feature with reversible fluorescence in a good linear relationship with pH values in the range of 1.0–13.0. What is more, N, S-CDs can be used as an ultrasensitive Ag+ probe sensor with the resolution up to 0.4 μM. This finding will expand the application of as prepared N, S-CDs in sensing and environmental fields.

P3HT-based organic solar cells (OSCs) have great advantages for commercialization including straightforward and scalable synthesis and well-developed roll-to-roll manufacturing technology. However, it is difficult to control the morphology of P3HT:acceptor blend films due to their highly crystalline characteristics. In this work, we designed and synthesized two thiazole (Tz) containing small molecular acceptors with an A–π–D–π–A type structure for the P3HT donor material. Both small molecules exhibit a good planar configuration due to incorporation of S⋯N noncovalent conformational locks. Upon changing the side chains, the interchain π–π stacking and the crystallinity of the small molecules were fine-tuned. Interestingly, P-IDTzR with bulky side chains exhibits suitable crystallinity, which matches well with P3HT. As a result, the P3HT:P-IDTzR blend films demonstrate optimal morphology, leading to a larger short circuit current (JSC), an enhanced fill factor (FF), and thus a larger power conversion efficiency (5.01%). This contribution provides important guidance in designing nonfullerene acceptors for high-performance P3HT based OSCs.

Janus heterostructural materials as photothermal agents with enhanced optical conversion capability are promising for artery inflammation treatment by the hyperthermia of macrophages, a primordial part in the artery inflammation response that can deteriorate into atherosclerosis and even break the vessels. Herein, a synthesis route of Janus Ag/Ag2S beads with hydrophilic ligands has been developed with a precise control over concentration, time and surface functionalization. These Ag/Ag2S heterodimers show desirable sizes of around 90 nm in diameter, in which Ag nanocrystals have a diameter of around 25 nm, and they exhibit a photothermal conversion efficiency of up to 50.0% as well as relatively low biotoxicity and good biocompatibility. Importantly, the as-prepared Janus Ag/Ag2S beads with a high biological safety can be effectively swallowed by macrophages and have a remarkable benefit of eliminating these cells from the original state of artery inflammation through the excellent photothermal effect of this material, without causing any further damage to the arteries and major organs in vivo. This study further promotes the development of treatment for vascular inflammation by the photothermal melting of macrophage cells in intima environments.

International audience; MXenes are highly conductive layered materials that are attracting a great interest for high-performance opto-electronics, photonics, and energy applications.. Their non-covalent functionalization with ad hoc molecules enables the production of stable inks of 2D flakes to be processed in thin-films. Here, the formation of stable dispersions via the intercalation of Ti3C2Tx with didecyldimethyl ammonium bromide (DDAB) yielding Ti3C2Tx–DDAB, is demonstrated. Such functionalization modulates the properties of Ti3C2Tx, as evidenced by a 0.47 eV decrease of the work function. It is also shown that DDAB is a powerful n-dopant capable of enhancing electron mobility in conjugated polymers and 2D materials. When Ti3C2Tx–DDAB is blended with poly(diketopyrrolopyrrole-co-selenophene) [(PDPP–Se)], a simultaneous increase by 170% and 152% of the hole and electron field-effect mobilities, respectively, is observed, compared to the neat conjugated polymer, with values reaching 2.0 cm2 V−1 s−1. By exploiting the balanced ambipolar transport of the Ti3C2Tx–DDAB/PDPP–Se hybrid, complementary metal–oxide–semiconductor (CMOS) logic gates are fabricated that display well-centered trip points and good noise margin (64.6% for inverter). The results demonstrate that intercalant engineering represents an efficient strategy to tune the electronic properties of Ti3C2Tx yielding functionalized MXenes for polymer transistors with unprecedented performances and functions.

Self‐assembly of semiconducting (macro)molecules enables the development of materials with tailored‐made properties which could be used as active components for optoelectronics applications. Supramolecular nanostructures combine the merits of soft matter and crystalline materials: They are flexible yet highly crystalline, and they can be processed with low‐cost solution methods. Photodetectors are devices capable to convert a light input into an electrical signal. To achieve high photoresponse, the photogenerated charge carriers should be transported efficiently through the self‐assembled nanostructures to reach the electrodes; this can be guaranteed via optimal π–electron overlapping between adjacent conjugated molecules. Moreover, because of the high surface‐to‐bulk ratio, supramolecular nanostructures are prone to enhance exciton dissociation. These qualities make supramolecular nanostructures perfect platforms for photoelectric conversion. This review highlights the most enlightening recent strategies developed for the fabrication of high‐performance photodetectors based on supramolecular nanostructures. We introduce the key figure‐of‐merit parameters and working mechanisms of organic photodetectors based on single components and p–n heterojunctions. In particular, we describe new methods to devise unprecedented planar and vertical devices to ultimately realize highly integrated and flexible photodetectors. The incorporation of ordered mesoscopic supramolecular nanostructures into macroscopic optoelectronic devices will offer great promise for the next generation of multifunctional and multiresponsive devices.

Summary Three-dimensional chromatin structures undergo dynamic reorganization during mammalian spermatogenesis; however, their impacts on gene regulation remain unclear. Here, we focused on understanding the structure-function regulation of meiotic chromosomes by Hi-C and other omics techniques in mouse spermatogenesis across five stages. Beyond confirming recent reports regarding changes in compartmentalization and reorganization of topologically associating domains (TADs), we further demonstrated that chromatin loops are present prior to and after, but not at, the pachytene stage. By integrating Hi-C and RNA-seq data, we showed that the switching of A/B compartments between spermatogenic stages is tightly associated with meiosis-specific mRNAs and piRNAs expression. Moreover, our ATAC-seq data indicated that chromatin accessibility per se is not responsible for the TAD and loop diminishment at pachytene. Additionally, our ChIP-seq data demonstrated that CTCF and cohesin remain bound at TAD boundary regions throughout meiosis, suggesting that dynamic reorganization of TADs does not require CTCF and cohesin clearance., Graphical Abstract, Highlights • Chromatin loops are reorganized during mouse spermatogenesis, being absent in pacSC • CTCF and cohesin remain bound to pacSC chromatin while TADs and loops are lost • Chromatin accessibility per se is not involved in the loss of TADs or loops in pacSC • A/B compartments switching is related to meiosis-specific mRNAs and piRNAs expression, Male Reproductive Endocrinology; Genomics; Transcriptomics

Two-dimensional metal organic framework nanosheets demonstrate various applications in chemical separation and purification, biological recognition and sensing, catalysis, and optoelectronics, though the exfoliation of metal organic framework nanosheets with good dispersibility are challenging. Here we report an efficient method for exfoliating a novel tellurophene-based two-dimensional metal organic framework with a branched polymer surfactant polyethylenimine ethoxylate to prepare single- and few-layer nanosheets. Furthermore, the hybrid ink is directly integrated as an electron extraction layer for high-performance organic solar cells, which exhibits enhanced power conversion efficiency in comparison to the polyethylenimine ethoxylate-based ones due to the suppressed charge recombination, tunable work function and improved conductivity. This contribution not only reports a novel method to prepare stable two-dimensional metal organic framework nanosheets but also opens an avenue for their applications in solar cells.

Mother Nature is always the best source for scientists to draw inspiration. Herein, a three-dimensional perylene diimide (PDI)-based molecular acceptor was designed and synthesized, in which six PDI units form an "iris-like" structure upon connecting with the hexaphenylbenzene core. Interestingly, this molecule is the nonfullerene acceptor containing most PDI units, which can absorb solar light to exhibit excellent power conversion efficiency, much more efficient than the natural flowers. This contribution presents an interesting example of learning from Mother Nature to design novel materials for applications.

Heteroatom-doped carbon dots (CDs) with a high photoluminescent quantum yield (PLQY) have recently attracted attention due to their applications in chemical sensors, photocatalysis, bioimaging, and drug delivery. Nitrogen and phosphorus are in close proximity to carbon in the periodic table and are key tracking elements in the field of biomedical imaging. These two elements alter the optical and electronic properties of CDs and help improve the fundamental understanding of their PLQY. This can also lead to multifunctional usage in photoimaging and photothermal therapy. However, most PLQYs resulting from the synthesis of P-doped CDs are currently below 50%. These CDs have limited usefulness in the fields of bioimaging and drug delivery. In this study, a single-step, high-efficiency hydrothermal method was applied to synthesize nitrogen and phosphorous-doped carbon dots ((N,P)-CDs) with a PLQY of up to 53.8% with independent emission behavior. Moreover, the CDs presented high monodispersity, robust excitation-independent luminescence, and stability over a large pH range. Spectroscopic investigations indicated that the PLQY of the (N,P)-CDs was primarily due to the addition of P and the passivation effect of the oxidized surface. The excellent fluorescence properties of (N,P)-CDs can be effectively and selectively quenched by Hg2+ ions. Such systems show a linear response in the 0–900 nM concentration range with a short response time, indicating their potential for applications in the fields of chemistry and biology.

As a class of the heteroatom-doped carbon materials, metal charge-transfer doped carbon dots (CDs) exhibited an excellent optical performance and were widely used as fluorescent probes. To improve fluorescence quantum yield (QY) remains one of the fundamental and challenging issues in the carbon dots field. Herein, we prepared a novel manganese doped CDs (Mn-CDs), which exhibited an ultrahigh quantum yield of 54%, the highest quantum yield for metal-doped CDs. Various spectroscopic measurements revealed an in situ change of dopant oxidation state during the synthesis. Our further study indicated the presence of metal–carbonate, which served as an important component for high quantum yield. We have also studied the reversibly switchable fluorescence property of Mn-CDs by adding Hg2+/S2–, as well as elucidating the underlying mechanism of this switching fluorescence phenomenon. By using the Mn-CDs as fluorescent probes, we developed an extremely sensitive detection method for heavy metal Hg2+ detection at a...

Constructing heterojunction is one of the methods to restrain the hole-electron recombination and thus improve the photoelectric property. In this work, PbS nanoparticles were grown directly on ultra thin MoS 2 nanosheets to fabricate 2D MoS 2 /PbS nanocomposites via a facile one-pot solvothermal route. PbS nanoparticles anchored on MoS 2 sheets exhibited high crystallinity and uniformity. The particle size can be controlled by varying the precursor concentration. The nanocomposites displayed higher photocurrent compared with pristine MoS 2 , due to the improved light harvesting and the construction of p-n heterojunction structure.

Heteroatom-doped carbon dots (CDs) with excellent optical characteristics and negligible toxicity have emerged in many applications including bioimaging, biosensing, photocatalysis, and photothermal therapy. The metal-doping of CDs using various heteroatoms results in an enhancement of the photophysics but also imparts them with multifunctionality. However, unlike nonmetal doping, typical metal doping results in low fluorescence quantum yields (QYs), and an unclear photoluminescence mechanism. In this contribution, we detail results concerning zinc doped CDs (Zn-CDs) with QYs of up to 35%. The zinc ion charges serve as a surface passivating agent and prevent the aggregation of graphene π–π stacking, leading to an increase in the QY of the Zn-CDs. Structural and chemical investigations using spectroscopic and first principle simulations further revealed the effects of zinc doping on the CDs. The robust Zn-CDs were used for the ultra-trace detection of Hg2+ with a detection limit of 0.1 μM, and a quench mechanism was proposed. The unique optical properties of the Zn-CDs have promise for use in applications such as in vivo sensing and future phototherapy applications.

Brass-coated steel cords are widely used as reinforcement material for rubber composites. The adhesion between steel cord and rubber is critical throughout the lifetime use of steel cord/rubber composites; thus, the adhesion mechanism has been a focus of the rubber industry for several decades. Various modern analytical instruments, such as X-ray spectroscopy and mass spectroscopy, have been applied to the study of this bonding interface. In this paper, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) was used to research the morphology of the steel cord surface and the adhesion mechanism. According to these morphology testing results, the rubber residue bands were observed be orientated and located mostly in Cu/Zn void areas. Further research reveals that macro-structure adhesion layer leads to interlocking mechanism for rubber residue.

Developing advanced catalysts that deliver high metal dispersion and outstanding catalytic activity is crucial for practical demand. In incipient wetness impregnation, the metal precursor–support surface interactions are very weak, which usually results in severe sintering and poor dispersion of the active component. In this work, Pt catalysts supported on a CZLP support are prepared via an impregnation method with pH adjustment of the precursor solutions. This means can enhance the Pt precursor–support interactions, and as a result, the Pt species are highly dispersed on the surface of the support. Meanwhile, the catalysts prepared by pH adjustment possess preferable reducibility, excellent thermostability and a smaller Pt nanoparticle size. Thus, the modified catalysts exert a positive effect on converting all target poisons, regardless of fresh or aged samples. When the pH of the impregnating solution is about 3, the catalyst exhibits the optimal performance. Therefore, this work provides a simple and valid synthesis route for advanced catalysts to purify vehicle exhaust.

Severe air pollution is pushing towards developing more efficient three-way catalysts (TWCs), especially for the elimination of NO and C3H8. In this work, the highly active κ-Ce2Zr2O8 phase was investigated and introduced into TWCs. First, we demonstrated that the cation-ordered pyrochlore-type structure was formed during severe reduction, accompanied by a Zr-rich surface as detected by CH3OH-FTIR. Although only partial κ-Ce2Zr2O8 nano-domains were observed by HRTEM, which nucleated within the fluorite matrix of CZ-950RO, they acted as a blasting fuse to boost the whole reduction. Moreover, the presence of κ-Ce2Zr2O8 phase strengthened Pd-CZ interaction, providing a route to generate highly reactive Pdδ+ (δ ≥ 3) and immobilize palladium nanoparticles through Pd-O-Ce bonds as evidenced by XPS and CO chemisorption. Thanks to the strengthened Pd-CZ interaction, Pd/950RO exhibited a stable activity toward NO and C3H8 conversion.

14%REOx 2.5%La2O3 33.5%ZrO2 50%Al2O3 (RE = Ce, Y, Pr) composites were prepared by a co-precipitation method. The Pd catalysts were obtained by an aqueous solution of Pd(NO3)2 loaded on the rare earths modified composites with an initial wet impregnated method. The experiment results show that catalytic activity of the rare earths modified Pd/La2O3 ZrO2 Al2O3 catalysts is better than bare sample for methane oxidation. The structural characterization results reveal that the rare earths modified Pd catalysts increase amounts of surface active oxygen species by X-ray photoelectron spectroscopy (XPS) analysis and improve the dispersion of active component from H2-temperature programmed reduction (H2-TPR) measurement compared with bare sample. Especially, Pd/14%Y2O3 2.5%La2O3 33.5%ZrO2 50%Al2O3 sample exhibits highly active stability, it is related to the Pd particles highly dispersion, which was observed by transmission electron microscope (TEM) images.

Two new small-molecular acceptors SF-2IIG and SF-4IIG were designed and synthesized to investigate the influence of the numbers of electron-deficient subunits of non-fullerene acceptors on the efficencies of photovotaic devices. The studies showed that these two acceptors have different optical absorbption, energy levels, charge transport mobilities. As a result, the efficiencies of SF-4IIG based solar cells are significantly higher than those of SF-2IIG based ones.

Two small-molecule non-fullerene acceptors, TPE-4PDI and SF-4PDI, and one polymer donor PTB7-Th are selected to construct ternary polymer solar cells with electron-cascade energy levels. In this novel combination, TPE-4PDI is employed as the third component to tune the morphology, achieve balanced hole/electron mobilities, enhance the exciton separation and improve the FF and J sc . Hence, the best efficiency of the ternary organic solar cells increase by ∼20% compared with the binary system.

Open circuit voltage (Voc) is a critical parameter for ternary organic solar cells, while its mechanism is obscure. Here we employed two non-fullerene molecules TPE-4PDI and FT-2PDI (perylenediimide, a PDI-based small molecule) to form acceptor alloys with ITIC-Th (indacenodithieno, an IDDT-based small molecule) for ternary systems. The results demonstrated that the experimental Voc values fit the simulation data accurately based on the equation not only in our new ternary systems but also in other reported small molecular alloy based ternary systems. More importantly, TPE-4PDI is more efficient to enhance the Voc of ternary solar cells as the third component than FT-2PDI, since TPE-4PDI possesses a larger quasi frontier orbital density (Ne) value. Thus, upon tuning the weight ratio of the TPE-4PDI:ITIC-Th acceptor alloy, high performance ternary solar cells with an efficiency over 11% were achieved. This contribution has shed light on understanding the mechanisms of ternary solar cells and demonstrated a method for enhancing Voc efficiently to achieve high performance solar cells.

Non-fullerene organic solar cells (OSCs) have attracted great attention due to their advantages including tunable light absorption and low cost fabrication. Many important strategies have been used to achieve high performing OSCs including increasing the charge transport mobility and reducing the energy loss (Eloss). In this contribution, two wide bandgap small molecular acceptors (IDTzCR and IDTCR) were designed and synthesized for OSCs. Through replacing the thiophene moieties with thiazole ones, charge transport mobility was increased due to introducing S⋯N noncovalent conformational locks, resulting in a significant enhancement of photovoltaic performances. Furthermore, IDTCR based OSCs afforded a record low Eloss value for “narrow bandgap donor:wide bandgap acceptor” systems due to the small LUMO/LUMO energy offset. This contribution showed a novel method to achieve excellent wide bandgap acceptors for OSCs and sheds lights on understanding the relationship between the materials properties and device performances.

Alkyl chain engineering has been employed to tune the physicochemical properties of conjugated polymers. Usually, several building blocks with different alkyl chains need to be synthesized in multiple steps, which is synthetically costly. Also, it is challenging to systematically tune the alkyl chains to enhance device performances due to the complex morphological characteristics of the conjugated polymers and the effects of molecular weight and purity. Here we designed and synthesized a series of conjugated polymers with similar molecular weights through random polymerization of BDT building blocks with two TT building blocks possessing different alkyl chains. Upon simply altering the molecular ratio of two TT units, the physicochemical characteristics, solid state packing, and photovoltaic properties of the conjugated polymers were systematically tuned. As a result, a conjugated polymer that can pair with both fullerene (PC71BM) and non-fullerene (ITIC-Th) acceptors to generate high power conversion efficiencies (10.3% and 9.1%, respectively) was achieved. This contribution provides a novel strategy for designing high performance conjugated polymers.

In this contribution, we developed a novel type of IDT-based small molecular acceptor, IDT-Tz, using thiazole as π-bridges. Through employing thiazole units as the π-bridges, nitrogen⋯sulfur noncovalent conformational locks were introduced to enhance the rigidity and planarity of the backbone, and thus reduce the reorganization energy, increase the charge transport mobility, and enhance the photovoltaic performance. The differences between the IDT-Tz and IDT-T based solar cells were fully investigated to understand the influences of the nitrogen⋯sulfur noncovalent conformational locks. The organic solar cells based on the IDT-Tz electron acceptor exhibit power conversion efficiencies (PCEs) as high as 8.4%, which is significantly higher than the PCE (4.1%) of the IDT-T based devices. This work demonstrated a novel strategy for enhancing the PCE of organic solar cells through introducing noncovalent conformational locks, which will be promising in designing novel high-performance non-fullerene materials.

International audience; Two-dimensional (2D) photodetecting materials have shown superior performances over traditional materials (e.g., silicon, perylenes), which demonstrate low responsivity (R) (

An efficient hole extraction layer (HEL) is critical to achieve high-performance organic solar cells (OSCs). In this study, we developed a pinhole-free and efficient HEL based on MoS2 quantum dots (QDs) combined with UV–ozone (UVO) treatment. The optophysical properties and morphology of MoS2 QDs and their photovoltaic performance are investigated. The results showed that MoS2 QDs can form homogeneous films and can be applied as an interfacial layer not only for donors with shallow highest occupied molecular orbital (HOMO) but also for those with deep HOMO energy levels after UVO treatment (O-MoS2 QDs). The solar cells based on O-MoS2 QDs yield a power conversion efficiency (PCE) of 8.66%, which is 71% and 12% higher than those of the OSCs with pristine MoS2 QD and O-MoS2 nanosheets, respectively, and the highest PCEs for OSCs containing MoS2 materials. Furthermore, the stability of solar cells based on MoS2 QDs is greatly improved in comparison with state-of-the-art PEDOT:PSS. These results demonstrate t...

Two analogous dimer and tetramer compounds, SF-PDI2 and SF-PDI4, were designed, theoretically calculated, synthesized, and developed as electron acceptors for organic solar cells. The effects of the number of the electron deficient building blocks on the optical absorption, energy levels, charge transport, morphology, crystallinity, and photovoltaic performance of the molecules were investigated. In combination with two different donors, PTB7-Th and PffBT4T-2OD, the results showed that increasing the numbers of PDI building blocks is beneficial to photovoltaic performance and leads to efficiency over 5%.

Three acceptor–acceptor (A–A) type conjugated polymers based on isoindigo and naphthalene diimide/perylene diimide are designed and synthesized to study the effects of building blocks and alkyl chains on the polymer properties and performance of all-polymer photoresponse devices. Variation of the building blocks and alkyl chains can influence the thermal, optical, and electrochemical properties of the polymers, as indicated by thermogravimetric analysis, differential scanning calorimetry, UV–vis, cyclic voltammetry, and density functional theory calculations. Based on the A–A type conjugated polymers, the most efficient all-polymer photovoltaic cells are achieved with an efficiency of 2.68%, and the first all-polymer photodetectors are constructed with high responsivity (0.12 A W−1) and detectivity (1.2 × 1012 Jones), comparable to those of the best fullerene based organic photodetectors and inorganic photodetectors. Photoluminescence spectra, charge transport properties, and morphology of blend films are investigated to elucidate the influence of polymeric structures on device performances. This contribution demonstrates a strategy of systematically tuning the polymeric structures to achieve high performance all-polymer photoresponse devices.

Heteroatom doped carbon dots, due to their excellent fluorescent properties and related applications, have attracted great attention from different fields. Herein, we reported for the first time a facile and economic approach to synthesize copper doped carbon dots (Cu-CDs) via a one-step hydrothermal approach. The chemical and fluorescent properties of these Cu-CDs as well as the mechanism involved for the enhancement of the fluorescent were investigated through various microscopic and spectroscopic analyses, such as transmission electron microscopy (TEM), fluorescence spectra, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). It is observed that the Cu-CDs with the average size of 3.76 nm are spherical and monodisperse. Additionally, the as-prepared Cu-CDs exhibited a strong emission at 440 nm when excited at 350 nm (λex) and the photoluminescence quantum yields (PLQY) reached 9.81% after the optimization of synthesis conditions. The excellent fluorescent properties of Cu-CDs make them great candidates for the selective and fast detection of Fe3+ in range of 0.001–200 μM, while the limit of detection (LOD) is 1 nM, which can be further applied to detect Fe3+ in human blood serum and other biomedical applications.

Developing three-way catalysts (TWCs) with improved activity and hydrothermal stability is essential for automotive exhaust treatment. Here, citric acid-assisted sol-gel method was used to prepare Pt/CeO2 TWCs, in order to obtain excellent activity and hydrothermal stability. The catalytic performance was evaluated on the conversions of pollutants CO, NOx and HC, and the catalysts were characterized using N2 adsorption-desorption, XRD, CO-adsorption, XPS and H2-TPR techniques. It is interesting to note that the Pt/CeO2 catalyst synthesized by sol-gel method (PC-sg) showed improved activity after 13 h exposure to steam and oxidizing atmosphere at 750 °C and exhibited comparable activity with the fresh catalyst (PC-im) prepared by impregnation method. Combined with characterization results, the improved performance for aged PC-sg catalysts is ascribed to the segregation of Pt out from ceria and dispersion on the surface of ceria after aging treatment, and the PC-sg catalysts had stronger metal-support interaction between metal and support to facilitate the creation of oxygen vacancies. The results obtained in this study showed a simple and effective method to synthesize TWCs with high activity and hydrothermal stability which provided valuable information for the design of advanced TWCs.

The adhesion energy of kerogen in continental and marine shale was innovatively discovered using the colloid probe technique with atomic-force microscopy (AFM). AFM results indicated that the adhesion force of kerogen was higher than the inorganic material in both the continental and marine shale samples. The chemical elements in the two kinds of samples were measured by energy-dispersive X-ray analysis with scanning electron microscopy (SEM). The chemical compositions of kerogen involved C═C bonding, C═O bonding, pyridine nitrogen, and pyrrole nitrogen, whereas the primary constituent involving inorganic matter was Si–O bonding. These results were confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The high percentages of C═C and C═O bonding in kerogen are attributed to the large dipole on the kerogen surface which allowed kerogen to contain liquid and gaseous hydrocarbons.

Multicolor carbon dots (C-dots) have excellent performance characteristics, high photoluminescence efficiency, ease of fabrication and low toxicity. C-dots have been used in a wide variety of fields including bioimaging, biomedicine, photocatalysis and environmental monitoring. The mass production of multicolor CDs using low-cost, facile methods is an important issue for future industrial applications. In this article, we reported a simple and highly effective way to prepare the multicolor C-dots and use them to detect heavy metal iron ions. Hydrochar acquired from food waste processed with hydrothermal carbonization (HTC) was used as the carbonaceous material for this process. Four colors of C-dots were obtained and included blue, green, yellow and red. These multicolor C-dots could be used as fluorescence probes with unique selectivity to detect the Fe3+ ion. The luminescence response ranged from 1 to 50 μM with a correlation coefficient of 0.9968. This discovery not only shows the high value-added products which can be obtained from food waste but can also lead to new developments in carbonaceous materials which can be used as “green resources”.

Triplet materials have been employed to achieve high-performing organic solar cells (OSCs) by extending the exciton lifetime and diffusion distances, while the triplet non-fullerene acceptor materials have never been reported for bulk heterojunction OSCs. Herein, for the first time, three triplet molecular acceptors based on tellurophene with different degrees of ring fusing were designed and synthesized for OSCs. Significantly, these molecules have long exciton lifetime and diffusion lengths, leading to efficient power conversion efficiency (7.52 %), which is the highest value for tellurophene-based OSCs. The influence of the extent of ring fusing on molecular geometry and OSCs performance was investigated to show the power conversion efficiencies (PCEs) continuously increased along with increasing the extent of ring fusing.

Heteroatom doped carbon dots (CDs), with high photoluminescence quantum yield (PLQY), are of keen interest in various applications such as chemical sensors, bio-imaging, electronics, and photovoltaics. Zinc, an important element assisting the electron-transfer process and an essential trace element for cells, is a promising metal dopant for CDs, which could potentially lead to multifunctional CDs. In this contribution, we report a single-step, high efficiency, hydrothermal method to synthesize Zn-doped carbon dots (Zn-CDs) with a superior PLQY. The PLQY and luminescence characteristic of Zn-CDs can be tuned by controlling the precursor ratio, and the surface oxidation in the CDs. Though a few studies have reported metal doped CDs with good PLQY, the as prepared Zn-Cds in the present method exhibited a PLQY up to 32.3%. To the best of our knowledge, there is no report regarding the facile preparation of single metal-doped CDs with a QY more than 30%. Another unique attribute of the Zn-CDs is the high monodispersity and the resultant highly robust excitation-independent luminescence that is stable over a broad range of pH values. Spectroscopic investigations indicated that the superior PLQY and luminescence of Zn-CDs are due to the heteroatom directed, oxidized carbon-based surface passivation. Furthermore, we developed a novel and sensitive biosensor for the detection of hydrogen peroxide and glucose leveraging the robust fluorescence properties of Zn-CDs. Under optimal conditions, Zn-CDs demonstrated high sensitivity and response to hydrogen peroxide and glucose over a wide range of concentrations, with a linear range of 10–80 μM and 5–100 μM, respectively, indicating their great potential as a fluorescent probe for chemical sensing.

Here, a facial and scalable method for efficient exfoliation of bulk transition metal dichalcogenides (TMD) and graphite in aqueous solution with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) to prepare single- and few-layer nanosheets is demonstrated. Importantly, these TMD nanosheets retain the single crystalline characteristic, which is essential for application in organic solar cells (OSCs). The hybrid PEDOT:PSS/WS2 ink prepared by a simple centrifugation is directly integrated as a hole extraction layer for high-performance OSCs. Compared with PEDOT:PSS, the PEDOT:PSS/WS2-based devices provide a remarkable power conversion efficiency due to the “island” morphology and benzoid–quinoid transition. This study not only demonstrates a novel method for preparing single- and few-layer TMD and graphene nanosheets but also paves a way for their applications without further complicated processing.

Acceptor alloys based on n-type small molecular and fullerene derivatives are used to fabricate the ternary solar cell. The highest performance of optimized ternary device is 10.4%, which is the highest efficiency for one donor/two acceptors-based ternary systems. Three important parameters, JSC , VOC , and FF, of the optimized ternary device are all higher than the binary reference devices.