Improving the performance of polymer solar cells by adjusting the crystallinity and nanoscale phase separation

In this paper, we report a high-perfornmnce P3HT/PCBM bulk-heterojunction solar cell with a power conversion efficiency of 4.85% fabricated by adjusting the polymer crystallinity and nanoscale phase separation using an ultrasonic irradiation mixing approach for the polymer. The grazing incidence X-ray diffraction, UV/Vis spectroscopic, and atomic force microscopic measurement results for the P3HT/PCBM blend films reveal that the P3HT/PCBM film fabricated by ultrasonic irradiation mixing of the P3HT and PCBM solutions for 10 min has a higher degree of crystallinity, a higher absorption efficiency, and better phase separation, which together account for the higher charge transport properties and photovoltaic cell performance.

Solvent-Assisted Supramolecular Assembly of Cyclotetrasiloxane– Functionalized Alkynylplatinum(II) Terpyridine Complexes

Our present study demonstrated and explored the solvent effects on the association mechanism of the supramolecular nanomaterials in a series of cyclo-tetrasiloxane-appended alkynylplatinum(II)terpyri-dine complexes.Through the delicate balance of molecular interactions,some of these complexes were found to exhibit molecular association prop-erties,with possible morphological transformation in response to solvent polarities.

Aggregation-induced emission luminogen for in vivo three-photon fuorescence lifetime microscopic imaging

Compared with visible light,near infrared(NIR)light has deeper penetration in biological tisues.Three-photon fuorescence microscopy(3PFM)can effectively utilize the NIR excitation to obtain high-contrast images in the deep tisue.However,the weak three photon fluorescence signals may be not well presented in the traditional fuorescence intensity imaging mode.Fluorescence lifetime of certain probes is insensitive to the intensity of the excitation laser.Moreover,fluorescence lifetimne imaging microscopy(FLIM)can detect weak signals by utilizing time correlated single photon counting(TCSPC)technique.Thus,it would be an improved strategy to combine the 3PFM imaging with the FLIM together.Herein,DCDPP-2TPA,a novel agegation-induced emission luminogen(AIEgen),was adopted as the fluorescent probes.The three-photon absorption cros-section of the AlEgen,which has a deep-red fluorescence emission,was proved to be large.DCDPP-2TPA nanoparticles were synthesized,and the three photon fluorescence lifetime of which was measured in water.Moreover,in vrivo thre-photon fuorescence lifetime microscopic imaging of a craniotomy mouse was conducted via a home made optical system.High contrast cerebrovascular images of different vertical depths were obtained and the maximun depth was about 600 pumn.Even reaching the depth of 600 pum,tiny capillary vessels as small as 1.9 pum could still be distinguished.The three photon fuorescence lifetimes of the capillaries in some representative images were in accord with that of DCDPP-2TPA nanoparticles in water.A vivid 3D reconstruction was further organized to present a wealth of lifetime information.In the future,the combination strategy of 3PFM and FLIM could be further applied in the brain functional imaging.

A ggregation-induced emission nanoparticles for in vivo three-photon fuorescence microscopic rat brain angiography

Rodents are popular biological models for physiological and behavioral research in neuroscience and rats are better models than mice due to their higher genome similarity to human and more accessible surgical procedures.However,rat brain is larger than mice brain and it needs powerful imaging tools to implement better penetration against the scattering of the thicker brain tissue.Three-photon fluorescence microscopy(3PFM)combined with near-infrared(NIR)excitation has great potentials for brain circuits imaging beause of its abilities of anti scattering,deep-tissue imaging,and high signal-to-noise ratio(SNR).In this work,a type of AIE lumninogen with red fuorescence was synthesized and encapsulated with Pluronic F-127 to make up form nano-particles(NPs).Bright DCDPP-2TPA NPs were employed for in trino three-photon fuorescent laser scanning microscopy of blood vessels in rats brain under 1550 nm femtosecond laser exci-tation.A fine three-dimensional(3D)reconstruction up to the deepness of 600 pm was achieved and the blood flow velocity of a selected vessel was measured in vrito as well.Our 3PFM deep brain imaging method simultaneously recorded the morphology and function of the brain blood vessels in vivo in the rat model.Using this angiography combined with the arsenal of rodent's brain disease,models can accelerate the neuroscience research and clinical diagnosis of brain disease in the future.

Supramolecular Self-assembly of Amphiphilic Alkynylplatinum(II)2,6-Bis(N-alkylbenzimidazol-2′-yl)pyridine Complexes

Alkynylplatinum(II)bzimpy complexes of trimethylammoniumbenzylethynyl ligand have been synthesized and characterized.Complexes with long alkyl chains have been found to exhibit interesting self-assembly properties in the acetonitrile solution.The amphiphilic nature of the complexes has led to the formation of nanorods,as revealed by electron microscopy experiments.Further increasing the polarity of the solvent media has given rise to the enhancement of low-energy emission.

Rational design of platinum(Ⅱ)complexes with orthogonally oriented triazolyl ligand with emission enhancement characteristics for cancer chemotherapy in vivo

The mitochondria are essential for tumorigenesis and have been regarded as important targets in cancer chemotherapy.Herein,the mitochondria-targeted platinum(Ⅱ)complexes have been prepared.The introduction of the triazole group with larger steric hindrance through post-click reaction converts the hybridization of carbon from sp to sp^(2),endowing the complexes with an orthogonally oriented ligand with restricted rotation and emission enhancement characteristics.Methylation of the triazolyl ligand has led to platinum(Ⅱ)complexes that can efficiently enter cancer cells and selectively accumulate in mitochondria,leading to significant enhancement in phosphorescence.In vivo anti-cancer investigations have demonstrated their distinct antitumor efficacy in substantial inhibition of tumor growth in breast cancer mice through dissipation of mitochondrial membrane potential,inducing apoptosis of tumor cell with negligibly systemic cytotoxicity.

Preparing lipid nanoparticles with tunable drug loading capacity and morphology via improved sequential nanoprecipitation

Nanotechnology hailed as a revolutionary new technology of the 21st century, has ignited a wave of innovation across diverse fields spanning chemistry, physics, materials science,medicine, engineering, and electronics. In 2016, Nature published an article titled “The nanolight revolution is coming”, underscoring that “virus-sized particles that emit light in every color could transform applications ranging from television displays to cancer treatment”.

Preparation and self-assembly of amphiphilic polymer with aggregation-induced emission characteristics

An amphiphilic polymer bearing tetraphenylethene (TPE) moiety was synthesized by convenient reactions. The polymer exhibits unique aggregation-induced emission (AIE) characteristics and can self-assemble to size-tunable particles in DMF/water mixtures. The polymer nanoparticles can be used for cell imaging, which provides a potential stable fluorescent tool to monitor the distribution of drugs and bioconjugates in living cells.

Effective enhancement of the emission efficiency of tetraphenylporphyrin in solid state by tetraphenylethene modification

Tetraphenylporphyrin(TPP) is a typical red-emitting luminogen showing evident aggregation caused quenching(ACQ) effect. To enhance its emission efficiency in solid state, four tetraphenylethene(TPE)units were attached to the four meso-positions of TPP core via ester group through a facile and efficient route. The derived compound(4(TPE-COO)-TPP) emits red fluorescence(peak at 655 nm) with a good quantum efficiency(F) of 7.5%, which is much higher than that of TPP(Φ～ 0.1%). In molecular aggregate formed in tetrahydrofuran(THF) and water mixtures, 4(TPE-COO)-TPP has a relative high F of 12%. The evidently subdued ACQ behavior can be ascribed to the propeller shape and bulky size of the TPE units,which prevent the close packing and strong p-p interaction of TPP cores. The loose molecular packing and weak interchromophore interactions were validated by different characterization methods including UV-visible absorption, steady state and transient fluorescence spectroscope, X-ray diffraction and scanning electronic microscope observations. It is noted that 4(TPE-COO)-TPP has an emission efficiency of 14.4% in dilute THF solution. This is due to the conjugation break between the TPP and TPE moieties, the rotational and vibrational motions of the phenyl groups cannot quench the fluorescence of 4(TPE-COO)-TPP.

A facile design for multifunctional AIEgen based on tetraaniline derivatives

Aniline oligomers have been widely used in many fields due to their excellent physicochemical properties. Owing to strong intermolecular interactions, their emission is always weakened or quenched when they are in high concentration or aggregated state, which greatly limits their fluorescent applications. Inspired by the concept of aggregation-induced emission(AIE), herein we introduced large steric groups onto the aniline oligomer to prevent the formation of packing structure. In particular, diphenyl vinyl group was bonded with oligomeric tetraaniline by a facile synthetic procedure with high yield. The obtained aniline oligomer derivative exhibited typical AIE features, which was also confirmed by density functional theoretical calculation. More importantly, this AIE oligomer was able to detect Fe^(3+) ions selectively and quantitatively. The fluorescence intensity decreased linearly along with the increment of Fe^(3+) concentration. Moreover, we demonstrated that this AIE oligomer could stain live bacteria, such as E. coli and S. aureus efficiently. All these results suggest that such a readily accessible and multifunctional tetraaniline derivative provides a new platform for the construction of fluorescent materials.

The specific detection of Cu(Ⅱ) using an AIE-active alanine ester

Cu（Ⅱ） detection is important because it plays crucial role in several biological processes and ecological systems.Fluorescent techniques have attracted more and more attention in Cu（Ⅱ） detection.In this report,we contribute a novel strategy to use fluorescence spectroscopy for Cu（Ⅱ） specific detection.The specificity relies on the fact that,of the many metal cations,only Cu（Ⅱ） can catalyze the hydrolyzation of a-amino acid ester.The novelty originates from the unique aggregation-induced emission（AIE） property of the fluorescent label.We designed a model a-amino acid ester（TPE-Ala） constructed with alanine and tetraphenylethene-functionalized methanol（TPE-methanol）.In comparison with the precursor TPE-Ala, TPE-methanol has lower solubility and is easy to form aggregates in water,thereby displaying a higher fluorescent response.Thus,the Cu（Ⅱ） catalyzed hydrolyzation can be monitored by recording the fluorescence enhancement and fluorescent detection Cu（Ⅱ） is rationally achieved.

Metallated conjugation in small-sized-molecular donors for solution-processed organic solar cells

Four metallated conjugated oligothiophenes,S-1,S-2,S-3 and S-4,with platinum(II)aryleneethynylenes as the electron-rich building block were synthesized to investigate their physicochemical and photovoltaic properties.These small molecules possess fairly low-lying HOMO energy levels which match with the LUMO energy level of the electron acceptor PC70BM([6,6]-phenyl-C71-butyric acid methyl ester).Using the simple process of spin-coating solution fabrication technique,S-1:PC70BM(1:4,w/w)based organic solar cells exhibiting a high Voc of 0.913 V,with a PCE value of 0.88%were developed.In contrast,the OSC device based on S-2:PC70BM(3:7,w/w)displayed a higher PCE of 1.59%with a higher Jsc value of 5.89m A cm–2.The device based on S-4:PC70BM(1:4,w/w)exhibited a PCE value of 1.56%,with a Voc of 0.917 V.

Design, Synthesis, Photophysical Studies and Electrochemistry of Carbazole-, Oxadiazole-, and Oxadiazole-Triarylamine-Containing Rhenium(Ⅰ) Diimine Alkynyl Complexes

A series of rhenium(I)diimine alkynyl complexes with various electron-and hole-transporting moieties has been synthesized and characterized.Their electronic absorption,emission and electrochemical properties have also been studied.

Aggregation-induced emission luminogen for specific identification of malignant tumour in vivo

Colorectal cancer(CRC)is still a major killer,mainly due to the lack of early detection biomarker with sensitivity/specificity.Conventional histopathology is the gold standard approach in practice,but there are still some issues(false diagnosis and long waiting period).Aggregation-induced emission(AIE)is a novel photophysical phenomenon which has been widely utilized for biological imaging in vitro,including malignant cells,showing remarkable imaging contrast and enhanced emission in high concentrated state.However,it is unclear if AIE dyes can identify malignant cells specifically in vivo.A great challenge for specific labeling of malignant cells is probably ascribed to the complex compositions in tumor tissues.Herein,an AIE dye-based mitochondria-targeted histological staining strategy was employed to localize cancer and the metastatic track in the fresh colorectal cancer.This novel approach holds great potential to revolutionize the clinical diagnosis and intervention for devastating malignancy.

Substituent-Mediated Transformation of Polynuclear Gold(I)-Sulfido Complexes—From Pentanuclear to Octadecanuclear Cluster-to-Cluster Transformation

Polynuclear gold complexes show diverse structures and bonding.An exploration into their transformation represents a challenging area of research.Herein,an unprecedented substituent-mediated transformation from pentagold(I)to octadecagold(I)complexes has been observed.These gold(I)-sulfido complexes with distinct structures have been fully characterized,and the transformation process has been monitored by NMR spectroscopy in solution state.

Synthesis of benzo[b]phosphole-based alkynylgold(I)complexes with resistive memory properties modulated by donor–acceptor chromophores

A class of benzo[b]phosphole-based alkynylgold(I)complexes has been synthesized and characterized.These complexes share a similar benzo-[b]phosphole ligand,in which the phosphole moiety is substituted with variousπ-conjugated units with different donor strengths,namely phenoxazinylphenyl,tris(di-tert-butylcarbazolyl)phenyl and 2,4-dimethylphenyl moieties.These phosphole-containing gold(I)complexes are found to be strongly luminescent in toluene with tunable emission maxima and possess solvatochromic behaviors,suggesting an emission of metal-perturbed intraligand charge transfer origin.Cyclic voltammetry studies reveal that the presence of gold(I)metal center strongly perturbs the electronic properties of the phosphole moiety of the resultant complexes,which can be further finetuned by the auxiliary ligand on the gold(I)center.In the resistive memory studies,devices based on these alkynylgold(I)complexes exhibit satisfactory binary memory behaviors,demonstrating low threshold voltages in narrow distributions,high durability and low misreading rates.Such performances are believed to be originated from a field-induced charge transfer of the alkynylgold(I)complexes,in which the electron-accepting phosphole-gold(I)unit plays a crucial role in stabilizing the charge transfer state and that led to the observed resistive switching and memory behavior.

AZIDE-ALKYNE CLICK POLYMERIZATION:AN UPDATE

The great achievements of click chemistry have encouraged polymer scientists to use this reaction in their field. This review assembles an update of the advances of using azide-alkyne click polymerization to prepare functional polytriazoles（PTAs） with linear and hyperbranched structures.The Cu（I）-mediated click polymerization furnishes 1,4-regioregular PTAs,whereas,the metal-free click polymerization of propiolates and azides produces PTAs with 1,4-regioisomer contents up to 90%.The PTAs display advanced functions,such as aggregation-induced emission,thermal stability,biocompatibility and optical nonlinearity.

Thiol-yne click polymerization

The research on using thiol-ene click reaction to synthesize sulfur-containing polymers with topological structures and advanced functional properties is a hot topic. However, the application of the thiol-yne reaction in the functional polymer preparation is limited and the thiol-yne click polymerization is to be further developed. In this review, we summarized recent research efforts on using thiol-yne click polymerization to synthesize polymers with topological structures. The sulfur-containing polymers were facilely prepared by photo-and thermo-initiated, amine-mediated, and transition-metal-catalyzed thiol-yne click polymerizations. These polymers are promising to be used as drug-delivery vehicles, high refractive index optical materials, photovoltaic materials, and biomaterials etc.

A general powder dusting method for latent fingerprint development based on AIEgens

Powder dusting method is the most practically useful approach for latent fingerprint development in the crime scene. Herein, a general powder dusting method has been explored for latent fingerprint development based on aggregation-induced emission luminogens(AIEgens). A series of tetraphenylethene(TPE) derivatives with multiple diphenylamine(DPA), namely, TPE-DPA,TPE-2 DPA and TPE-4 DPA, were selected as candidates to dope with magnetic powders and applied for latent fingerprint development. After screening, the magnetic powder 3 doped with TPE-4 DPA proves to be the best, in terms of fluorescent intensity, resolution and adhesiveness. Afterwards, the magnetic powder 3 was applied for visualization of latent fingerprint on various smooth and porous substrates, including glass, stainless steel, leaf, ceram, plastic bag, lime wall, wood and paper money.Specific details, such as island, core, termination and bifurcation, can be clearly observed for the fluorescent fingerprint images.

Readily accessible rhodamine B-based photoresponsive material

A photochromic rhodamine B-based material containing Cd(Ⅱ)as bridge was facilely prepared.The 4-methoxylsalicylaldehyde rhodamine B hydrazone Cd(Ⅱ)complex displayed unusual ring-open response upon 365 nm UV irradiation,exhibiting long photochromic lifetime and good fatigue resistance.The UV-induced ring-open of the complex led to a distinct color and fluorescence change in acetonitrile.A new mechanism was put forward:salicylaldehyde part in the complex underwent UV-promoted isomerization from enol-form to keto-form,enhancing the chelation of Cd(Ⅱ)and yielding the ring-opening rhodamine B part.Compared to other reported photochromic systems,this new photochromic material offered attractive new insights into the development of low cost photochromic materials with good performance.