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The development of high mobility organic laser semiconductors with strong emission is of great scientific and technical importance, but challenging. Herein, we present a high mobility organic laser semiconductor, 2,7-diphenyl-9H-fluorene (LD-1) showing unique crystallization-enhanced emission guided by elaborately modulating its crystal growth process. The obtained one-dimensional nanowires of LD-1 show outstanding integrated properties including: high absolute photoluminescence quantum yield (PLQY) approaching 80 %, high charge carrier mobility of 0.08 cm2 V-1 s-1 , Fabry-Perot lasing characters with a low threshold of 86 μJ cm-2 and a high-quality factor of ≈2400. Furthermore, electrically induced emission was obtained from an individual LD-1 crystal nanowire-based light-emitting transistor due to the recombination of holes and electrons simultaneously injected into the nanowire, which provides a good platform for the study of electrically pumped organic lasers and other related ultrasmall integrated electrical-driven photonic devices.

While manganese (Mn2+)-doped chalcogenide and perovskite CsPbX3 nanocrystals (NCs) have been extensively investigated, the research of color-tunable dual-emissive Mn2+-incorporated two-dimensional ...

Purpose This study aimed to develop a multi-long noncoding RNA (lncRNA) signature for the prediction of gastric cancer (GC) based on differential gene expression between recurrence and nonrecurrence patients. Methods By repurposing microarray expression profiles of RNAs from The Cancer Genome Atlas (TCGA), we performed differential expression analysis between recurrence and nonrecurrence patients. A prognostic risk prediction model was constructed based on data from TCGA database, and its reliability was validated using data from Gene Expression Omnibus database. Furthermore, the lncRNA-associated competing endogenous RNA (ceRNA) network was constructed, namely, DIANA-LncBasev2 and starBase database. Results We identified 363 differentially expressed RNAs (317 mRNAs, 18 lncRNAs, and 28 microRNAs [miRNAs]). Principal component analysis showed that the seven-feature lncRNAs screened by support vector machine–recursive feature elimination algorithm was more informative for predicting recurrence of GC in comparison with the eight-feature lncRNAs screened by random forest–out-of-bag algorithm. Four of the seven-feature lncRNAs including LINC00843, SNHG3, C21orf62-AS1, and MIR99AHG were chosen to develop a four-lncRNA risk score model. This risk score model was able to distinguish patients with high and low risk of recurrence, and was tested in two independent validation sets. The ceRNA network of this four-lncRNA signature included 10 miRNAs and 178 mRNAs. The mRNAs significantly related to the Wnt-signaling pathway and relevant biological processes. Conclusion A useful four-lncRNA signature recurrence was established to distinguish GC patients with high and low risk of recurrence. Regulating the relevant miRNAs and Wnt pathway might partly affect GC metastasisby.

Two-dimensional (2D) cocrystals open a new way to get 2D functional materials via crystal engineering instead of molecular engineering. Here, large-area 2D cocrystals with length reaching several millimeters with strong near-infrared (NIR) absorption have been successfully designed and prepared. Driven by the intermolecular charge-transfer (CT) interactions, zinc tetraphenylporphyrin (donor) and C 60 (acceptor) self-assemble into a NIR cocrystals with absorption wavelength up to 1080 nm. By tailoring the growth solvents and processes, the cocrystal morphologies can be tuned from 1D nanowires, 2D nanosheets to large-area 2D cocrystal films with length reaching several millimeters. Impressively, due to the highly ordered donor-acceptor arrangement, the CT absorption in the 2D cocrystals is significantly enhanced and becomes comparable to singlet absorption. The uniform 2D cocrystals, with enhanced CT absorption in the NIR region, displays a high responsivity of 2424 mA/W to NIR light and a fast response time of 0.6 s. The excellent device performance can be attributed to the generation of long-lived free charge carriers as revealed by transient absorption spectroscopy and the optimization of device configuration. This work shows an example of controlled growth of 2D cocrystals for broadband photodetectors, which reveals the brilliant future of cocrystal films for high-performance electronics and paves their way towards large-scale, integrated, flexible, practical applications.

The utilization of highly efficient fluorescent materials for latent fingerprints (LFPs) is attractively important for criminal investigations but remains challenging. Herein, we developed a low-cost near-infrared (NIR) emission composite powder made up of organic fluorophores doped into the montmorillonite (MMT) medium for the visualization of LFPs based on powder dusting. Our design of twisted donor–acceptor structures of CASN and TASN not only enables NIR emissions at 650 and 686 nm but also assures high solid state photoluminescence quantum yields (Φsolid) of 0.17 and 0.32, respectively. Furthermore, TASN doped into the MMT medium has the merits of a high adsorptive capacity and a mass ratio as low as 10%. Compared with traditional magnetic and red fluorescent powders, the TASN/MMT powder could give reliable fluorescent images of LFPs with a higher contrast and resolution, under visible light (405 nm) rather than harmful UV (365 nm) excitation. Florescence fingerprint images of specific level 1–3 details on different substrates, including both smooth and rough surfaces, can be obtained within 10 s by mobile phone photography. These results prove that the TASN/MMT powder is a promising candidate for the forensic sciences.

Polymorph-selective synthesis of organic heterostructured architectures represents a tough challenge due to the diversity of organic species and the growth complexity of seed crystals with specific polymorphs as well as complicated epitaxial relationships among diverse constituent materials. Herein, we employ three polymorphic π-conjugated molecules to construct three types of binary organic heterostructures based on a molecular design principle via a solution seeded-mediated strategy, where pre-existing crystals with a specific polymorph serve as seeds to afford epitaxial growth of another organic crystal. As a consequence, the crystal form of the second growth component can be exclusively determined regardless of the synthetic procedures. Indeed, epitaxial growth of these dual-color-emitting organic heterostructures was realized depending on the small lattice mismatch between two specific polymorphs of any two constituent materials, which is determined by their structural compatibility and elaborate selection of the seed crystals. The present work offers a promising platform to understand polymorph-selective synthesis of organic heterostructured microstructures, which may be used to achieve unprecedented photonic and electronic properties.

Organic semiconductors with long-range exciton diffusion length are highly desirable for optoelectronics but currently remain rare. Here, the estimated diffusion length of singlet excitons (LD ) in 2,6-diphenyl anthracene (DPA) crystals grown by solvent evaporation was shown to be up to approximately 124 nm. These crystals showed a previously unseen parallelogram morphology with layer-by-layer edge-on molecular stacking, isotropic optical waveguiding, radiation rate and non-radiation rate constants of 0.15 and 0.26 ns-1 respectively, as well as good field-effect transistor hole mobility and theoretically computed strong electronic couplings as high as 109 meV. Photoresponse experiments revealed that the photoconductivity of DPA crystals is surprisingly not related to the radiative pathway but associated with rapid exciton diffusion to the crystal surface for charge separation and carrier bimolecular recombination. Taken together, DPA was shown to be a promising semiconducting material for a new organic optoelectronics paradigm.

An electron donor/acceptor pair comprising perylene (Pe) and 9,10-dicyanoanthracene (DCA) was specifically designed to construct organic charge-transfer (CT) alloys via weak CT interaction through a solution co-assembly route. By adjusting the molar ratio between Pe and DCA, we achieve color- and dimension-tunable CT alloy assemblies involving one-dimensional (1D) (DCA)1-x (Pe)x (0 ≤ x ≤10 %) microribbons and two-dimensional (2D) (Pe)1-y (DCA)y (0 ≤ y ≤5 %) nanosheets as a consequence of energy transfer from DCA or α-Pe to Pe-DCA CT complex. Importantly, dimension-related optical waveguiding performances are also revealed: continuously adjustable optical loss in 1D (DCA)1-x (Pe)x microribbons and successive conversion from isotropic waveguide to anisotropic waveguide in 2D (Pe)1-y (DCA)y nanosheets. The present work provides a desired platform for in-depth investigation of light-harvesting organic CT alloy assemblies, which show promising applications in miniaturized optoelectronic devices.

Large-area multicolor laser arrays on the nano- to microscale are key components for the development of on-chip nanophotonics and next-generation color display technology, which remain a formidable...

Although organic polariton condensation has been recently demonstrated, they only utilize the photon part of polaritons and ignore the excitonic contribution because the polariton-polariton and polariton-reservoir interactions are weak in organic microcavities owing to the absence of Coulomb exchange-interactions between Frenkel excitons. We demonstrate highly efficient and strongly polarization-dependent polariton condensates in a microcavity consisting of an H-aggregate organic single-crystalline microbelt sandwiched between two silver reflectors. Benefitting from the advantages of vibronic coupling in H-aggregates and heavy exciton-like polaritons, both macroscopic coherent polariton ground-state population and high-energy quantized-modes are observed. The measurements are qualitatively reproduced based on simulations of the spatiotemporal polariton dynamics. The observation of low threshold polariton lasing, the ease of fabrication, and the potential for efficient electronic charge injection make microcrystals of organic semiconductors attractive candidates for continuous wave and electrically pumped functional photonic polariton circuits and organic polariton lasers, operating at room temperature.

Xin Zhang,1,* Hejing Huang,2,* Ziran Wei,1,* Zhenxin Zhu,1 Dejun Yang,1 Hongbing Fu,1 Jiapeng Xu,1 Zunqi Hu,1 Yu Zhang,1 Qing You,1 Xin Huang,1 Ronglin Yan,1 Weimin Wang,1 Qingping Cai1 1Department of Gastrointestinal Surgery, Changzheng Hospital, Second Military Medical University, Shanghai, People’s Republic of China; 2Department of Ultrasound, Changzheng Hospital, Second Military Medical University, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Qingping Cai; Ronglin Yan Tel +86-21-81885601; +86-21-81885603Fax +86-21-81886000Email caiqingping@smmu.edu.cn; yanronglin@smmu.edu.cnBackground: What is the optimal neoadjuvant chemotherapy (NAC) regimen for locally advanced gastric cancer (LAGC) remains debatable. The objective of this study was to compare the efficacy of docetaxel+oxaliplatin+S-1 (DOS) vs oxaliplatin+S-1 (SOX) as NAC for LAGC.Methods: Data of 248 LAGC patients who received either DOS or SOX as NAC in our hospital between January 2010 and January 2018 were reviewed retrospectively. Propensity score matched (PSM) analysis was applied to minimize the selection bias in both groups. Prognostic factors were screened by univariate and multivariate Cox regression analyses.Results: Of the 248 LAGC patients included, 180 patients were subjected to the PSM analysis. Patients in DOS group showed a better tumor response to NAC, higher radical resection rate and R0 resection rate than those in SOX group. The overall survival (OS) rate in DOS group was better than that in SOX group, although the overall incidence of Grade 3/4 NAC-related toxicity in DOS group was higher, as represented by leukopenia and neutropenia. Multivariate analysis revealed that the NAC regimen, cTNM stage and the R0 resection rate were independent prognostic factors. In addition, patients with TLND less than 16 population showed a worse OS rate. Subgroup analysis indicated that patients benefited from the addition of docetaxel regardless of the clinical T stage, but those with high clinical N stages (N2-3) did not.Conclusion: DOS is a safe and feasible NAC regimen for LAGC, which is worth popularizing in clinical practice.Keywords: locally advanced gastric cancer, neoadjuvant chemotherapy, radical gastrectomy, propensity score matched analysis, docetaxel

Creating nano-to-macroscopic-sized artificial actuators in response to light has been a challenging issue. Herein, we describe the design, synthesis, and operation of a photomechanical molecular crystal (PMMC) that exhibits well-controlled multiple photo-driven motions, including translation, rotation, and jumping, by adjusting the irradiation sites. Theoretical calculation discloses that conversion of light energy into macroscopic motion occurs through a molecular conformation change between the excited and ground states mediated by ultrafast conical internal conversion, making the photomechanical/recovery responses a rapid cycle. Therefore, our PMMCs can complete the directional and continuous motions using only one laser beam. We also demonstrated the actuated rotation of a cross-shaped sample by rotating the polarization of the laser beam at a rate of >2 Hz, like a dancer under a spotlight. This finding could lead to remote-controlled micrometer-sized vehicles and valves on solid substrates.

Organic solid-state semiconductor lasers are attracting ever-increasing interest for their potential application in future photonic circuits. Despite the great progress made in recent years, an organic laser from 3D chiral structures has not been achieved. Now, the first example of an organic nano-laser from the micro-helix structure of an achiral molecule is presented. Highly regular micro-helixes with left/right-handed helicity from a distyrylbenzene derivative (HM-DSB) were fabricated and characterized under microscope spectrometers. These chiral micro-helixes exhibit unique photonic properties, including helicity-dependent circularly polarized luminescence (CPL), periodic optical waveguiding, and length-dependent amplified spontaneous emission (ASE) behavior. The successful observation of laser behavior from the organic micro-helix extends our understanding to morphology chirality of organic photonic materials and provides a new design strategy towards chiral photonic circuits.

Patterning of single-crystalline lead halide perovskites (APbX3, X = Cl, Br, I) into laser arrays has attracted considerable research attention. However, the random size distribution leads to an unrepeatable lasing action, which makes the fabrication of highly ordered laser arrays a formidable task. Beyond those single-crystalline units, here, we report novel hybrid Concrete-like perovskites (CPs) of CsPbBr3@MABr to obtain high-quality optical micro-cavity arrays for lasing. Similar to the case of Concrete, ∼100 nm inorganic CsPbBr3 coarse aggregates bonded with finer cement-like MABr, and presented a huge enhancement in optical gain (G = 200 cm−1) and deformable plasticity. Well-controlled dimensions and uniform geometries enable the CP micro-rings and nanowires to function as high-quality whispering-gallery mode (WGM) and Fabry–Perot (FP) lasers, respectively. The “Concrete” perovskite strategy provides new insights for the fabrication of high-quality laser arrays with promising applications in integrated coherent light sources and photonics.

Nanowire laser arrays for integrated on-chip optical interconnects demand the uniformity of lasing wavelengths from different modules, which, however, is challenging owing to inevitable heterogeneity in subunit fabrication. Herein, we demonstrated a facile method to prepare uniform nanolaser arrays based on a transverse lateral Fabry–Perot (FP) microresonator built within single-crystalline organic microribbons of 1,4-bis((E)-2,4-dimethylstyryl)-2,5-dimethylbenzene (6M-DSB). Theoretically, spectroscopic and crystallographic results together reveal that short-axis brickwork-packing and long-axis uniaxial-alignment of 6M-DSB molecules result in a mixed Hj-type aggregation within microribbons. On the one hand, such a kind of Hj-type aggregation exhibits enhanced radiative decay and therefore 100% photoluminescence quantum yield for minimizing the singlet–triplet annihilation and reabsorption of laser photons owing to triplet absorption. On the other hand, the uniaxial alignment gives rise to a transverse lateral FP microresonator along the width of 6M-DSB microribbons, rather than a longitudinal microresonator in conventional nanowire lasers. By positioning a microribbon onto a PDMS pad with patterned grooves, only the suspended parts support transverse waveguiding and high quality FP resonances. A proof-of-concept 1 × 4 transverse nanolaser array constructed from the same microribbon was demonstrated with almost identical lasing thresholds, wavelengths and FP resonances, providing coupled lasing subunits for integrated organic photonics.

Optical activity, also called circular birefringence, is known for two hundred years, but its applications for topological photonics remain unexplored. Unlike the Faraday effect, the optical activity provokes rotation of the linear polarization of light without magnetic effects, thus preserving the time-reversal symmetry. In this work, we report a direct measurement of the Berry curvature and quantum metric of the photonic modes of a planar cavity, containing a birefringent organic microcrystal (perylene) and exhibiting emergent optical activity. This experiment, performed at room temperature and at visible wavelength, establishes the potential of organic materials for implementing non-magnetic and low-cost topological photonic devices., Most work in topological photonics is performed in periodically structured systems. Here, the authors directly measure the nontrivial Berry curvature of the photonic modes of a birefringent continuous organic system exhibiting emergent optical activity.

Organic solid-state lasers (OSSLs) have been paid great attention due to their ease-of-fabrication, low cost and tailor-made molecular tunability. Optical gain materials of OSSLs are currently focused on fluorescent materials, which can bring only 25% exciton utilization for future current-injection OSSLs due to spin statics under electrical excitation. While thermally active delayed fluorescent (TADF) materials can obtain a theoretical 100% internal quantum efficiency by harvesting triplet excitons. However, OSSLs based on TADF materials remain largely unexplored yet. Here, we report the first TADF-based OSSL from whispering-gallery mode microring resonator arrays fabricated by a confined solution-growth method. The newly designed TADF emitter of carbozyl borondifluoride curcuminoid derivative, namely, CAZ-A, when doped into a host matrix of 4,4′-bis(N-carbazolyl)-1,10-biphenyl (CBP), reaches the highest gain-coefficient of 640 cm–1 at 4 wt %. These MRs with well-controlled sizes and uniform geometries c...

Compared with their 3D counterparts, layered 2D Ruddlesden–Popper perovskites (2D RPPs) with the formula of (A′)2An–1PbnX3n+1 exhibit improved photo and moisture stability. To develop flexible sing...

Stimulated emission depletion (STED) nanoscopy is a powerful sub-diffraction imaging tool to probe subcellular structures and organelles. Conventional organic dyes require high STED power (PSTED) to obtain sub-diffraction resolution, leading to serious photo-bleaching. Herein, this study demonstrates highly emissive silica-coated core-shell organic nanoparticles (CSONPs) as a new type of photostable probe with ultrahigh stimulated emission depletion efficiency for low-power super-resolution STED nanoscopy. The CSONPs offer (i) efficient red emission with high solid-state fluorescence quantum yields around 0.6, (ii) large Stokes shift of 150 nm and (iii) high photostability owing to silica shell protection. The stimulated emission depletion efficiency (η) of CSONPs was extremely high up to η = 99% (the highest value reported so far) with a saturation intensity as low as Isat = 0.18 MW cm-2. Moreover, this research demonstrates the super-resolution imaging of living HeLa cells stained using CSONPs with a lateral spatial resolution of 63 nm at an extremely low depletion power of ISTED = 0.89 MW cm-2 and a long-term stability >600 s at η = 80% without obvious fatigue. The excellent and comprehensive performances of the CSONPs are promising for super-resolution imaging in biological applications.

Stimulated emission depletion (STED) nanoscopy plays a key role in achieving sub-50 nm high spatial resolution for subcellular live-cell imaging. To avoid re-excitation, the STED wavelength has to be tuned at the red tail of the emission spectrum of fluorescent probes, leading to high depletion laser power that might damage the cell viability and functionality. Herein, with the highly emissive silica-coated core-shell organic nanoparticles (CSONPs) enabling a giant Stokes shift of 150 nm, ultralow power STED is achieved by shifting the STED wavelength to the emission maximum at 660 nm. The stimulated emission cross section is increased by ∼20-fold compared to that at the emission red tail. The measured saturation intensity and lateral resolution of our CSONP are 0.0085 MW cm-2 and 25 nm, respectively. More importantly, long-term (>3 min) dynamic super-resolution imaging of the lysosomal fusion-fission processes in living cells is performed with a resolution of 37 nm.

Thermally activated delayed fluorescent (TADF) emitters have received great attention in organic light-emitting diodes and laser diodes because of high exciton utilization efficiency and low optical loss caused by triplets. However, the direct observation of lasing emission from nondoped TADF microcrystals has yet to be reported. Here, we demonstrated a three-color (green, yellow, and red) microlaser from three nondoped TADF microcrystals with well-controlled geometries. The temperature-dependent dynamic analyses testify that the regenerated singlets which originated from the reverse intersystem crossing process at room temperature are beneficial for population inversion and reduce triplet-absorption/annihilation optical loses, together resulting in thermally activated lasing actions. Thanks to single-crystalline structures of TADF emitters, the relationship between triplet-harvesting capability and the molecular structure was systematically investigated. The results not only offer rational design of pure TADF gain materials but also provide guidance for the high-performance electrically driven organic solid-state lasers and multicolor laser integration.

Two-photon excited fluorescence (TPEF) bio-probes are important for tissue imaging. Here, we demonstrated a strategy for highly emissive, photostable, low cytotoxicity and full-color tunable TPEF organic nanoparticles (ONPs) comprising of commercially available dyes doped in a TPEF host matrix. Because of efficient Forster resonance energy transfer (FRET), near-IR laser pumping light can be strongly absorbed by host matrix molecules via a two-photon absorption (TPA) process and transferred to dopant dyes, which then emit visible photons in different colors from blue, green, and yellow to red with high quantum yields. Our strategy significantly enhanced the photo-stability and TPEF of dopant dyes in ONPs, avoiding the need to resort to specially engineered expensive dyes.

Here, we design and synthesize an organic laser molecule, 2,7-diphenyl-9H-fluorene (LD-1), which has state-of-the-art integrated optoelectronic properties with a high mobility of 0.25 cm2 V-1 s-1, a high photoluminescence quantum yield of 60.3%, and superior deep-blue laser characteristics (low threshold of Pth = 71 μJ cm-2 and Pth = 53 μJ cm-2 and high quality factor (Q) of ∼3100 and ∼2700 at emission peaks of 390 and 410 nm, respectively). Organic light-emitting transistors based on LD-1 are for the first time demonstrated with obvious electroluminescent emission and gate tunable features. This work opens the door for a new class of organic semiconductor laser molecules and is critical for deep-blue optical and laser applications.

Integrating electronics and photonics is critically important for the realization of high-density and high-speed optoelectronic circuits. However, it remains challenging to achieve this target due to the difficulty of merging many different areas of science and technology. Here, we show an organic integrated optoelectronic device, namely, organic field-effect optical waveguide, integrating field-effect transistor and optical waveguide together. In such device, the propagation of optical waveguide in the active organic semiconductor can be tuned by the third terminal—the gate electrode of transistor, giving a controllable modulation depth as high as 70% and 50% in parallel and perpendicular directions of charge transport versus optical waveguide, respectively. Also, the optical waveguide with different directions can turn the field-effect of the device with the photodependence ratio up to 14800. The successful integration of active field-effect transistor with semiconductor waveguide modulator expands opportunities for creating scalable integration of electronics and photonics in a chip., Despite recent advances in organic optoelectronics development, integration of electronics and photonics in a chip remains a challenge. Here, the authors demonstrate organic field-effect optical waveguides that control propagating photons by the electric field produced in an organic transistor.

Miniaturized nanowire nanolasers of 3D perovskites feature a high gain coefficient; however, room-temperature optical gain and nanowire lasers from 2D layered perovskites have not been reported to date. A biomimetic approach is presented to construct an artificial ligh-harvesting system in mixed multiple quantum wells (QWs) of 2D-RPPs of (BA)2 (FA)n-1 Pbn Br3n+1 , achieving room-temperature ASE and nanowire (NW) lasing. Owing to the improvement of flexible and deformable characteristics provided by organic BA cation layers, high-density large-area NW laser arrays were fabricated with high photostability. Well-controlled dimensions and uniform geometries enabled 2D-RPPs NWs functioning as high-quality Fabry-Perot (FP) lasers with almost identical optical modes, high quality (Q) factor (ca. 1800), and similarly low lasing thresholds.

Rational design and fabrication of organic microcrystal polymorphs with controlled molecular-stacking arrangements provides an effective way to optimize the optical and electronic properties, but remains challenging owing to weak van der Waals’ intermolecular interactions associated with the kinetic process of crystal growth. In this paper, we synthesized a novel compound, 1,4-dimethoxy-2,5-di[bithiophenestyryl]benzene (TPDSB), which combines the high optical-gain of the oligomeric phenylene vinylene (OPV) core-moiety with enhanced charge transportation offered by bithiophene end-groups. Controlled fabrication of one-dimensional microwires (1D-MWs) and two-dimensional microdisks (2D-MDs) was achieved by controlling the growth temperature: 1D-MWs at 30 °C as a kinetically favored morphology and 2D-MDs at 2 °C as a thermodynamically stable product. We found that though both 1D-MWs and 2D-MDs belong to the monoclinic phase, their different molecular packing arrangements caused by different molecular conformations result in distinctly different optical and electrical properties. In particular, well-faceted 1D-MWs and 2D-MDs can function as yellow-emissive Fabry–Perot (FP) and red-emissive whispering-gallery-mode (WGM) microlasers, respectively. Furthermore, single-crystal data reveal that TPDSB molecules adopt a planar conformation in 1D-MWs with relatively loose molecular-packing into rolled π-stacks, while twist molecules in 2D-MDs exhibit tight molecular-packing into slipped π-stacks. This makes 2D-MDs have a higher PL quantum yield (Φ), a lower lasing threshold and a higher carrier mobility than 1D-MWs. Our results demonstrated that these easily solution-processed organic microcrystal polymorphs might be optimized on the way to realizing electrically driven organic lasers.

Development of nanowire photonics requires integration of different nanowire components into highly ordered functional heterostructures. Herein, we report a sequential self-assembly of binary molecular components into branched nanowire heterostructures (BNHs) via lattice-matched epitaxial growth, in which the microribbon backbone of 2,5-Bis(5-tert-butyl-2-benzoxazolyl)thiophene (BBOT) functions as blue-emitting microlaser source to pump the nanowire branches of BODIPY. By constructing Au electrodes on both branch sides and measuring the photocurrent in them, we successfully realize the integration of an organic laser and a power meter in a single device. This work provides a new insight into the integration of 1D organic nanostructures into BNHs for realizing organic multifunctional photonic devices.

Development of luminescence probes with polarized and narrow emissions simultaneously is helpful for removing multiply scattered light and enables multiplexing detection, but it remains challenging to use conventional organic dyes, fluorescence proteins, and quantum dots. Here, we demonstrated smart one-dimensional microlaser probes (MLPs) by coating a thin layer of silica shell on the surface of organic nanowires (ONWs) of 1,4-dimethoxy-2,5-di[4′-(methylthio)styryl]benzene (TDSB), namely, ONW@SiO2 core–shell structures. Different from the Fabry–Perot (FP) cavity formed between two end-faces of semiconductor nanowires, whispering gallery mode (WGM) microresonators are built within the rectangular cross section of ONW@SiO2 MLPs. This enables a lasing threshold as low as 1.54 μJ/cm2, above which lasing emissions are obtained with a full width at half-maximum (fwhm) 83%. Meanwhile, small dimensions of ONW@SiO2 MLPs with a side-length of ca. 500 nm and a length of 3...

Integration of multi-color semiconductor nanowire lasers (NWLs) on a silicon substrate is a very challenging task, owing to both the material lattice mismatch and the incompatible growth temperature. Recently, organic–inorganic perovskite (CH3NH3PbX3; X = Cl, Br, I) NWLs have been developed using a surface-initiated solution-growth method, which, however, requires post-synthesis transfer of nanowires from a growth substrate to a silicon wafer for device fabrication. Herein, we report multi-color perovskite nanowire lasers on arbitrary substrates (silicon or quartz substrates) through kinetically controlled growth followed by gas-phase halide exchange. First, we developed an antisolvent–vapor-diffusion induced crystallization method to kinetically direct the growth of CH3NH3PbCl3 towards single-crystal nanowires rather than the crystal habit of plate-like morphology. The ratio of nanowires to square microplates was adjusted to be as high as 97% : 3%. Then we introduced a gas-phase halide-anion-exchange reaction to convert chloride nanowires into bromide and iodide ones upon exposure to the vapor of HX (X = Br, I), while preserving both the high crystallinity and the nanowire morphology. Upon optical excitation, Fabry–Perot lasing around 550 and 785 nm occurs from CH3NH3PbBr3 and CH3NH3PbI3 nanowires with an onset of 9.8 and 9.2 μJ cm−2, respectively, with a maximum quality factor of 1260.

Background and Aims Routine gastroesophagostomy has been shown to have adverse effects on the recovery of digestive functions and quality of life because patients typically experience reflux symptoms after proximal gastrectomy. This study was performed to assess the feasibility and quality of life benefits of a novel reconstruction method termed Roux-en-Y anastomosis plus antral obstruction (RYAO) following proximal partial gastrectomy. Methods A total of 73 patients who underwent proximal gastrectomy from June 2015 to June 2017 were divided into two groups according to digestive reconstruction methods [RYAO (37 patients) and conventional esophagogastric anastomosis with pyloroplasty (EGPP, 36 patients)]. Clinical data were compared between the two groups retrospectively. Results The mean operative time for digestive reconstruction was slightly longer in the RYAO group than in the EGPP group. However, the incidence of postoperative short-term complications did not differ between the RYAO and the EGPP groups. At the 6-month follow-up, the incidence rates of both reflux esophagitis and gastritis were lower in the RYAO group than in the EGPP group (P = 0.002). Additionally, body weight recovery was better in the RYAO group (P = 0.028). The scale tests indicated that compared with the patients in the EGPP group, the patients in the RYAO group had significantly reduced reflux, nausea and vomiting and reported improvements in their overall health status and quality of life (all P < 0.05). Conclusion RYAO reconstruction may be a feasible procedure to reduce postoperative reflux symptoms and the incidence of reflux esophagitis and gastritis, thus improving patient quality of life after proximal gastrectomy.

Obesity is a severe medical problem endangering the health of individuals worldwide. Sleeve gastrectomy (SG), one of the most commonly performed bariatric procedures, has been widely applied to the treatment of such patients. Currently, the potential mechanisms underlying the significant weight loss and metabolic improvement after SG have been well studied. First, and most importantly, by removing a large volume of stomach, the SG directly or indirectly restricts food intake. Then, there are alterations in the absorption and metabolism of both macro- and micronutrients, which may benefit or worsen the patients' well-being. Another profound change is enhanced secretion of the satiety gut hormone and reduced secretion of the hunger hormone as a consequence of the operation. Additionally, adjustment of gastrointestinal motility, alteration in the gut microbial community, and an inflammatory response were found after surgery. Therefore, the purpose of the present review was focused on such hypotheses and to compile the accumulated facts on the physiologic mechanism of bariatric surgery so that these results can help improve the understanding of how SG produces substantial weight loss and a significant improvement in the metabolism of patients with metabolic syndrome.

Efficient red‐emitting aggregation‐induced emission luminogens with tunable organelle‐specific anchoring of PIZ‐CN and PID‐CN are designed and synthesized. By virtue of their large Stokes shift, excellent photostability, and low stimulated emission depletion (STED) saturation intensity, the dynamic motions of lysosomes and mitochondria are recorded with high resolution under low STED power.

Photoinitiated interfacial electron transfer from organic semiconductors to inorganic ones is extremely important in organic/inorganic hybrid optoelectronic materials. Herein, we have prepared hybrid ZnO nanorods by grafting TDPP and TTDPP molecules through carboxyl acid groups. The steady-state spectroscopy results revealed that photoluminescence was subjected to severe quenching in the hybrid nanocomposites. Furthermore, time-resolved fluorescence and femtosecond transient absorption data verified the occurrence of the interface charge transfer between TDPP or TTDPP molecules and ZnO nanorods in the hybrid nanocomposites. The high performance UV-vis photodetector based on the TTDPP/ZnO hybrid have been fabricated with a photoresponsivity of 16.9 A W−1 and an on/off ratio as high as 104. The excellent visible-light photoresponse of the hybrid device can be attributed to the broadband absorption after the anchoring of the TTDPP compound on the surface of ZnO nanorods, the efficient cascade charge transfer process and the excellent capability of ZnO nanorods to provide direct and stable pathways for the transport of photogenerated electrons toward the collection electrode. This provides guidelines for the construction of organic/inorganic hybrids for optoelectronic applications.

Organic solid-state lasers (OSSLs) have been a topic of intensive investigations. Perylenediimide (PDI) derivatives are widely used in organic thin-film transistors and solar cells. However, OSSLs based on neat PDIs have not been achieved yet, owing to the formation of H-aggregates and excimer trap-states. Here, we demonstrated the first PDI-based OSSL from whispering-gallery mode (WGM) hexagonal microdisk (hMD) microcavity of N,N'-bis(1-ethylpropyl)-2,5,8,11-tetrakis(p-methyl-phenyl)-perylenediimide (mp-PDI) self-assembled from solution. Single-crystal data reveal that mp-PDI molecules stack into a loosely packed twisted brickstone arrangement, resulting in J-type aggregates that exhibit a solid-state photoluminescence (PL) efficiency φ15%. Moreover, we found that exciton-vibration coupling in J-aggregates leads to an exceptional ultrafast radiative decay, which reduces the exciton diffusion length, in turn, suppresses bimolecular exciton annihilation (bmEA) process. These spectral features, plus the optical feedback provided by WGM-hMD microcavity, enable the observation of multimode lasing as evidenced by nonlinear output, spectral narrowing, and temporal coherence of laser emission. With consideration of high carrier-mobility associated with PDIs, hMDs of mp-PDI are attractive candidates on the way to achieve electrically driven OSSL.

Obtaining a large open-circuit voltage (VOC ) and high short-circuit current density (JSC ) simultaneously is important in improving power conversion efficiency (PCE) of organic photovoltaics. The ternary strategy with using a higher lowest unoccupied molecular orbital (LUMO) level nonfullerene acceptor (NFA) guest can achieve increased VOC , yet JSC is decreased or maintained, so it's still a challenge to offer increased VOC and JSC values concurrently via the newly presented VOC -increased ternary strategy. To overcome this issue, a new narrow bandgap NFA TT-S-4F is reported by introducing 3,6-dimethoxylthieno[3,2-b]thiophene (TT) as π-spacers to connect electron-rich core with terminal groups, so as to upshift the LUMO level and extend π-system. When adding 10% TT-S-4F into binary system based on PTB7-Th:IEICO-4F, the higher-LUMO-level of TT-S-4F, the increased charge mobilities, the reduced trap-assisted combination loss, and a finer nanofiber structure and increased phase separation size are obtained, which simultaneously promotes JSC , VOC , and fill factor (FF), thus obtaining an optimal PCE (12.5% vs 11.5%). This work illustrates that an extending conjugated backbone with large π-spacers and inclusion of alkylthiophenyl side-chains is a concept to synthesize NFA guests for use on the VOC -increased ternary strategy that enables to realize simultaneously increased JSC , VOC , and FF.

DPP-based conjugated polymers exhibit a broad optical absorption and high motilities for hole and electron, all of which will be advantageous to high photocurrents and good fill factors in OPV. However, their power conversion efficiency (PCE) still lag behind other polymer donor materials. In order to understand the reason hindering the PCE improvement, it is especially important to reveal the underlying electronic processes in Donor-Acceptor blending active layer. Through optical pump terahertz probe investigation, we found that the combination of fast exciton separation and long carrier lifetime will convenient to optic-electricity conversion efficiency. Although high charge mobility lead to long carrier lifetime, the difficulty of exciton separation in narrow band gap polymer DPPDTT is a key factor affecting device efficiency.

Organic solid-state lasers (OSSLs) have been widely investigated during the past decades, owing to their amenability to low-cost and low-temperature processing, compatibility with plastic substrates, and broad spectral tunability. A variety of optical resonators have been applied for optically pumped OSSLs, including planar waveguide Fabry-Perot (FP) microcavity, distributed feedback (DFB), whispering-gallery mode (WGM) microring microresonator, and photonic band-gap structures. Nevertheless, electrically driven OSSLs remain still a great challenge, partially because the conflicting requirement between large stimulated emission and high charge carrier mobility narrows the range of organic semiconductor gain materials available for electrically driven OSSLs. Recently, we demonstrated that organic microcrystal with well-defined dimensions and different polymorphisms can serve as microresonators for fundamental investigation of optical confinement effect on laser behaviors, such as nanowire FP and microdisk WGM microlasers. Moreover, organic single crystals are ideal for use as high-mobility materials, because their long-range ordered structures minimize traps and are free from grain boundaries. Therefore, organic microcrystals provide a platform to combine high carrier transport, efficient optical gain, and microresonator together on the way to develop electrically pumped organic lasers. In this talk, I will present our research on the photonic performance of molecular microcrystal microcavities and the latest breakthroughs toward organic microlaser devices. Overall, organic microcrystals bring tunable optical properties based on molecular design, size-dependent light confinement in low-dimensional structures, and various device geometries for nanophotonic integration.

The small organic molecule p-distyrylbenzene (DSB) has been controllably prepared into one-dimensional microwires (1D-MWs) and 2D rhombic microdisks (2D-RMDs) by modulating the growth kinetics in the process of morphology growth. These as-prepared organic microcrystals, 1D-MWs and 2D-RMDs, exhibit a shape-dependent microcavity effect in that the single 1D-MW can act as a Fabry-Perot (FP) mode lasing resonator while the individual 2D-RMD functions as the whispering-gallery-mode (WGM) microcavity. Moreover, as compared with the 1D FP resonators, there exists a higher quality factor (Q) in the WGM lasing resonator under the identical optical path length. Significantly, the lasing threshold, Eth = 1.02 μJ/cm2, of 2D-RMDs is much lower than Eth = 2.57 μJ/cm2 of 1D-MWs. Our demonstration can give the direction for the development of the organic solid-state microlasers.

Near-infrared (NIR) lasers are key components for applications, such as telecommunication, spectroscopy, display, and biomedical tissue imaging. Inorganic III-V semiconductor (GaAs) NIR lasers have achieved great successes but require expensive and sophisticated device fabrication techniques. Organic semiconductors exhibit chemically tunable optoelectronic properties together with self-assembling features that are well suitable for low-temperature solution processing. Major blocks in realizing NIR organic lasing include low stimulated emission of narrow-bandgap molecules due to fast nonradiative decay and exciton-exciton annihilation, which is considered as a main loss channel of population inversion for organic lasers under high carrier densities. Here we designed and synthesized the small organic molecule (E)-3-(4-(di-p-tolylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one (DPHP) with amphiphilic nature, which elaborately self-assembles into micrometer-sized hemispheres that simultaneously serves as the NIR emission medium with a photoluminescence quantum efficiency of ∼15.2%, and the high-Q (∼1.4 × 10(3)) whispering gallery mode microcavity. Moreover, the radiative rate of DPHP hemispheres is enhanced up to ∼1.98 × 10(9) s(-1) on account of the exciton-vibrational coupling in the solid state with the J-type molecular-coupling component, and meanwhile the exciton-exciton annihilation process is eliminated. As a result, NIR lasing with a low threshold of ∼610 nJ/cm(2) is achieved in the single DPHP hemisphere at room temperature. Our demonstration is a major step toward incorporating the organic coherent light sources into the compact optoelectronic devices at NIR wavelengths.

A laser array on the nano-and microscale is a key component for integration in photonic devices, but remains a challenge when using semiconductor nanowire lasers. Here we report a low-threshold lateral-cavity microlaser, formed between two lateral-faces of a single-crystalline organic microbelt (OMB) of 1,4-dimethoxy-2,5-di-[4'-(cyano)styryl]benzene (COPV). By cutting a single OMB into six pieces by a top-down two-photon processing technique, we successfully fabricated a compact and uniform 1 x 6 microlaser array along the length direction of the OMB. The microlasers had excellent reproducibility and addressable high precision, thus making them attractive candidates as miniaturized coherent light sources for future nanophotonics.

A novel quinacridone-based polymer containing a vinylene linkage, PQTE, was synthesized and exhibited higher performance both in organic thin-film transistors and solar cells than that of the reference polymer PQ2T. On introducing the vinylene linkage, a strong interchain interaction is obtained with a short π–π stacking distance of 3.49 A in the polymer PQTE, which is responsible for the highest mobility of 0.67 cm2 V−1 s−1 reported to date for quinacridone-based semiconductors. More significantly, the incorporation of a thienylene–vinylene–thienylene unit contributes to good miscibility between PQTE and PC71BM. Because of the effective intercalation of PC71BM in the PQTE lamellar structure, a high power conversion efficiency of 3.9% was achieved without any additives or post-treatments. Our rational molecular design qualifies quinacridone as a promising building block simultaneously in high performance polymer thin-film transistors and solar cells.

3D organic-inorganic hybrid perovskites have featured high gain coefficients through the electron-hole plasma stimulated emission mechanism, while their 2D counterparts of Ruddlesden-Popper perovskites (RPPs) exhibit strongly bound electron-hole pairs (excitons) at room temperature. High-performance solar cells and light-emitting diodes (LEDs) are reported based on 2D RPPs, whereas light-amplification devices remain largely unexplored. Here, it is demonstrated that ultrafast energy transfer along cascade quantum well (QW) structures in 2D RPPs concentrates photogenerated carriers on the lowest-bandgap QW state, at which population inversion can be readily established enabling room-temperature amplified spontaneous emission and lasing. Gain coefficients measured for 2D RPP thin-films (≈100 nm in thickness) are found about at least four times larger than those for their 3D counterparts. High-density large-area microring arrays of 2D RPPs are fabricated as whispering-gallery-mode lasers, which exhibit high quality factor (Q ≈ 2600), identical optical modes, and similarly low lasing thresholds, allowing them to be ignited simultaneously as a laser array. The findings reveal that 2D RPPs are excellent solution-processed gain materials potentially for achieving electrically driven lasers and ideally for on-chip integration of nanophotonics.

Fabrication of semiconductor nanowire laser arrays is very challenging, owing to difficulties in direct monolithic growth and patterning of III–V semiconductors on silicon substrates. Recently, methylammonium lead halide perovskites (MAPbX3, X = Cl, Br, I) have emerged as an important class of high-performance solution-processed optoelectronic materials. Here, we combined the “top–down” fabricated polydimethylsiloxane rectangular groove template (RGT) with the “bottom-up” solution self-assembly together to prepare large-scale perovskite nanowire (PNW) arrays. The template confinement effect led to the directional growth of MAPbX3 along RGTs into PNWs. We achieved precise control over not only the dimensions of individual PNWs (width 460–2500 nm; height 80–1000 nm, and length 10–50 μm) but also the interwire distances. Well-defined dimensions and uniform geometries enabled individual PNWs to function as high-quality Fabry–Perot nanolasers with almost identical optical modes and similarly low-lasing thresho...

Self-assembled nano/microcrystals of organic semiconductors with regular faces can serve as optical microresonators, which hold a promise for studying the light confinement and the light-matter interaction. Here, single crystalline microribbons of 1,4-bis(2-(4-(N,N-di(p-tolyl)amino)phenyl)-vinylbenzene (DPAVB) are synthesized with well-controlled sizes by a facile solution-exchange method. We find that individual microribbon can work as Fabry-Perot (FP) resonator along its width (w), in which strong coupling of optical modes with excitons results in the formation of exciton polaritons (EPs). The dispersion relation of E ∼ kz of EPs is constructed by extracting the energies (E) of FP resonances at integer multiples of π/w in the wavevector (kz) space. By simulating the significantly curved dispersion of EPs with a two coupled harmonic oscillator model, a coupling strength between 0.48 and 1.09 eV are obtained. Two coupling regimes are classified: in regime I, the coupling strength is constant at 0.48 eV fo...

One-dimensional (1D) ribbon-like and two-dimensional (2D) square-like perylene crystals were prepared in a controlled manner via a simple drop-casting solution method by changing the temperature and concentration of the solution. Based on SAED and XRD results, both the ribbon and square perylene crystals belong to the α phase. From further optical and electronic characterizations, we find that perylene crystals show unique dimension-dependent optoelectronic properties. In 2D crystal, photons propagate along the two edge directions without anisotropy, indicating that the optical waveguide property may not be related to molecular packing. Propagation of photons along the direction of the axis in the 1D crystal seems to be a little more efficient than that in the 2D structure. Moreover, hole mobility of the 1D crystal is the same as that along the [001] direction of the 2D square sheet, while hole carriers are transported along the two directions of square sheet with an anisotropy about 2.3. This excellent example shows that the optical waveguide and field-effect mobility of an organic crystal can be tuned by controlling the number of dimensions of the crystal during the synthesis.

Development of nanoscale optical components has been an active topic in nanophotonics, with potential for use in high-speed data highways on electronic chips. Organic semiconductors are low-cost advanced materials, exhibiting ease of processing, along with chemically tunable electronic and optical properties. Moreover, the large binding energy and oscillator strength of Frenkel excitons make polaritons in organic semiconductors highly stable at room temperature. Here, we demonstrate a waveguide exciton–polariton (WGEP) sub-microlaser from a built-in Fabry–Perot (FP) cavity based on self-assembled organic nanowires (ONWs) of 1,4-chloride-2,5-di[4′-(methlthio)styryl-benzene (CDSB). The strong light–matter coupling results in strong optical confinement, enabling ONWs to guide and steer WGEP laser light on the wavelength scale. An optical router was realized using a dendritic structure as a result of efficient polariton waveguiding and photoluminescence (PL) anisotropy of ONWs, opening a new route to future photonic circuits.