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The rapid development of the Internet of Things and wearable electronics has generated growing interest in creating high-performance and visually striking polymer thermoelectric (TE) devices. However, existing polymer TE materials have yet to fully meet these diverse demands. In this study, imprinted porous polymer films are introduced that exhibit both high TE performance and a spectrum of structural colors. The porous architecture not only preserves excellent charge transport properties but also significantly enhances phonon-like scattering, resulting in a more than 50% reduction in thermal conductivity for the PDPPSe-12 film. This leads to a 170% increase in the figure of merit (ZT), achieving a peak value of 0.52 at 363 K. Furthermore, the highly ordered porous structure imparts the PDPPSe-12 films with both a wide range of structural colors and remarkable stretchability, making them ideal for wearable TE generators. This approach is widely applicable to various polymeric systems, offering a novel strategy for advancing state-of-the-art plastic TE materials through microstructural engineering., (© 2024 Wiley‐VCH GmbH.)

Organic cocrystals formed through multicomponent self-assembly have attracted significant interest owing to their clear structure and tunable optical properties. However, most cocrystal systems suffer from inefficient long-wavelength emission and low phosphorescence efficiency due to strong non-radiative processes governed by the energy gap law. Herein, an efficient long-lived red afterglow is achieved using a pyrene (Py) cocrystal system incorporating a second component (NPYC4) with thermally activated delayed fluorescence (TADF) and ultralong organic phosphorescence (UOP) properties. The cocrystal (NPYC4-Py) not only inherits the excellent luminescence of its monomeric counterparts, but also exhibits unique dual-mode characteristics, including persistent TADF and UOP emission with a high quantum yield of 58% and a lifetime of 362 ms. The precise cocrystal stacking distinctly reveals that intermolecular interactions lock the cocrystal formation and weaken the intermolecular π-π interactions between NPYC4 and Py, thereby stabilizing the excited triplet excitons. Furthermore, the favorable energy level of NPYC4 acts as a bridge, reducing the energy gap between the S1 and T1 states for Py, therefore activating its red phosphorescence from Py. This research provides direct insights into achieving efficient red UOP through co-crystallization., (© 2024 Wiley‐VCH GmbH.)

Photo-patterning of polymer semiconductors using photo-crosslinkers has shown potential for organic circuit fabrication via solution processing techniques. However, the performance of patterning, including resolution (R), UV light exposure dose, sensitivity (S), and contrast (γ), remains unsatisfactory. In this study, a novel conjugated polymer based photo-crosslinker (PN3, Figure 1a) is reported for the first time, which entails phenyl-substituted azide groups in its side chains. Due to the potential π-π interactions between the conjugated backbone of PN3 and those of polymer semiconductors, PN3 exhibits superior miscibility with polymer semiconductors compared to the commonly used small molecule photo-crosslinker 4Bx (Figure 1a). Consequently, photo-patterning of polymer semiconductors with PN3 demonstrates improved performance with much lower UV light exposure dose, higher S and higher γ compared to 4Bx. By utilizing electron beam lithography, patterned arrays of polymer semiconductors with resolutions down to 500 nm and clearer edges are successfully fabricated using PN3. Furthermore, patterned arrays of PDPP4T, the p-type semiconductor (Figure 1b), after being doped, can function as source-drain electrodes for fabricating field-effect transistors (FETs) with comparable charge mobility and significantly lower sub-threshold swing value compared to those with gold electrodes., (© 2024 Wiley‐VCH GmbH.)

A number of quinoidal molecules with symmetric end-capping groups, particularly dicyanomethylene units, have been synthesized for organic optoelectronic materials. In comparison, dissymmetric quinoidal molecules, characterized by end-capping with different groups, are less explored. In this paper, we present the unexpected formation of new formal quinoidal molecules, which are end-capped with both dicyanomethylene and triphenylphosphonium moieties. The structures of these dissymmetric quinoidal molecules were firmly verified by single crystal structural analyses. On the basis of the control experiments and DFT calculations, we proposed the reaction mechanism for the formation of these dissymmetric quinoidal molecules. The respective zwitterionic forms should make contributions to the ground state structures of these quinoidal molecules based on the analysis of their bond lengths and aromaticity and Mayer Bond Orbital (MBO) calculation. This agrees well with the fact that negative solvatochromism was observed for these quinoidal molecules. Although these new quinoidal molecules are non-emissive both in solutions and crystalline states, they become emissive with quantum yields up to 51.4 % after elevating the solvent viscosity or dispersing them in a PMMA matrix. Interestingly, their emissions can also be switched on upon binding with certain proteins, in particular with human serum albumin., (© 2024 Wiley-VCH GmbH.)

Polymer semiconductors hold tremendous potential for applications in flexible devices, which is however hindered by the fact that they are usually processed by halogenated solvents rather than environmentally more friendly solvents. An effective strategy to boost the solubility of high-performance polymer semiconductors in nonhalogenated solvents such as tetrahydrofuran (THF) by appending hydroxyl groups in the side chains is herein presented. The results show that hydroxyl groups, which can be easily incorporated into the side chains, can significantly improve the solubility of typical p- and n-types as well as ambipolar polymer semiconductors in THF. Meanwhile, the thin films of these polymer semiconductors from the respective THF solutions show high charge mobilities. With THF as the processing and developing solvents these polymer semiconductors with hydroxyl groups in the side chains can be well photopatterned in the presence of the photo-crosslinker, and the charge mobilities of the patterned thin films are mostly maintained by comparing with those of the respective pristine thin films. Notably, THF is successfully utilized as the processing and developing solvent to achieve high-density photopatterning with ≈82 000 device arrays cm -2 for polymer semiconductors in which hydroxyl groups are appended in the side chains., (© 2024 Wiley‐VCH GmbH.)

In recent decades, polymer semiconductors, extensively employed as charge transport layers in devices like organic field-effect transistors (OFETs), have undergone thorough investigation due to their capacity for large-area solution processing, making them promising for mass production. Research efforts have been twofold: enhancing the charge mobilities of polymer semiconductors and augmenting their mechanical properties to meet the demands of flexible devices. Significant progress has been made in both realms, propelling the practical application of polymer semiconductors in flexible electronics. However, integrating excellent semiconducting and mechanical properties into a single polymer still remains a significant challenge. This review intends to introduce the design strategies and discuss the properties of high-charge mobility stretchable conjugated polymers. In addition, another key challenge faced in this cutting-edge field is maintaining stable semiconducting performance during long-term mechanical deformations. Therefore, this review also discusses the development of healable polymer semiconductors as a promising avenue to improve the lifetime of stretchable device. In conclusion, challenges and outline future research perspectives in this interdisciplinary field are highlighted., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Non-benzenoid polycyclic aromatic hydrocarbons (PAHs) have received a lot of attention because of their unique optical, electronic, and magnetic properties, but their synthesis remains challenging. Herein, we report a non-benzenoid isomer of peri-tetracene, diazulenorubicene (DAR), with two sets of 5/7/5 membered rings synthesized by a (3+2) annulation reaction. Compared with the precursor containing only 5/7 membered rings, the newly formed five membered rings switch the aromaticity of the original heptagon/pentagon from antiaromatic/aromatic to non-aromatic/antiaromatic respectively, modify the intermolecular packing modes, and lower the LUMO levels. Notably, compound 2 b (DAR-TMS) shows p-type semiconducting properties with a hole mobility up to 1.27 cm 2  V -1  s -1 . Moreover, further extension to larger non-benzenoid PAHs with 19 rings was achieved through on-surface chemistry from the DAR derivative with one alkynyl group., (© 2023 Wiley-VCH GmbH.)

The thermoelectric (TE) performance of organic materials is limited by the coupling of Seebeck coefficient and electrical conductivity. Herein a new strategy is reported to boost the Seebeck coefficient of conjugated polymer without significantly reducing the electrical conductivity by incorporation of an ionic additive DPPNMe 3 Br. The doped polymer PDPP-EDOT thin film exhibits high electrical conductivity up to 1377 ± 109 S cm -1 but low Seebeck coefficient below 30 µV K -1 and a maximum power factor of 59 ± 10 µW m -1 K -2 . Interestingly, incorporation of small amount (at a molar ratio of 1:30) of DPPNMe 3 Br into PDPP-EDOT results in the significant enhancement of Seebeck coefficient along with the slight decrease of electrical conductivity after doping. Consequently, the power factor (PF) is boosted to 571 ± 38 µW m -1 K -2 and ZT reaches 0.28 ± 0.02 at 130 °C, which is among the highest for the reported organic TE materials. Based on the theoretical calculation, it is assumed that the enhancement of TE performance for the doped PDPP-EDOT by DPPNMe 3 Br is mainly attributed to the increase of energetic disorder for PDPP-EDOT., (© 2023 Wiley-VCH GmbH.)

Molecular probes which can be modulated, functionalized and used to visualize the processes are highly desirable for understanding and manipulating biological systems. Geometric cis and trans isomers of tetraphenylethene (TPE) emerge as attractive candidates to fulfill these tasks thanks to the unique aggregation-induced emission properties, tailorable structures, and responsiveness to external stimuli. This minireview focuses on cis and trans isomers of TPE derivatives that are functionalized with molecular recognition units for fluorescence detection, bioimaging and cancer therapy. The effects of molecular geometry on fluorescence property, target binding ability and biological activity are summarized. The feasibility to in vitro and in vivo switch molecular configuration and thus bio-activity is discussed. Finally, the future development and challenges are discussed in view of TPE-based stereoisomers for targeted sensing and imaging-guided modulation of biological processes., (© 2023 Wiley-VCH GmbH.)

Emissive organic semiconductors are highly demanding for organic light-emitting transistors (OLETs) and electrically pumped organic lasers (EPOLs). However, it remains a great challenge to obtain organic semiconductors with high carrier mobility and high photoluminescence quantum yield simultaneously. Here, a new design strategy is reported for highly emissive ambipolar and even n-type semiconductors by introducing perfluorophenyl groups into polycyclic aromatic hydrocarbons such as perylene and anthracene. The results reveal that 3,9-diperfluorophenyl perylene (5FDPP) exhibits the ambipolar semiconducting property with hole and electron mobilities up to 0.12 and 1.89 cm 2 V -1 s -1 , and a photoluminescence quantum yield of 55%. One of the crystal forms of 5FDPA exhibits blue emission with an emission quantum yield of 52% and simultaneously shows the n-type semiconducting property with an electron mobility up to 2.65 cm 2 V -1 s -1 , which is the highest value among the reported organic emissive n-type semiconductors. Furthermore, crystals of 5FDPP are utilized to fabricate OLETs by using Ag as source-drain electrodes. The electroluminescence is detected in the transporting channels with an external quantum efficiency (EQE) of up to 2.2%, and the current density is up to 145 kA cm -2 , which are among the highest values for single-component OLETs with symmetric electrodes., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Non-benzenoid acenes containing heptagons have received increasing attention. We herein report a heptacene analogue containing a quinoidal benzodi[7]annulene core. Derivatives of this new non-benzenoid acene were obtained through an efficient synthetic strategy involving an Aldol condensation and a Diels-Alder reaction as key steps. The configuration of this heptacene analogue can be modulated from a wavy to a curved one by just varying the substituents from a (triisopropylsilyl)ethynyl group to a 2,4,6-triisopropylphenyl (Trip) group. When mesityl (Mes) groups are linked to the heptagons, the resulting non-benzenoid acene displays polymorphism with a tunable configuration from a curved to a wavy one upon varying the crystallization conditions. In addition, this new non-benzenoid acene can be oxidized or reduced by NOSbF 6 or KC 8 to the respective radical cation or radical anion. Compared with the neutral acene, the radical anion shows a wavy configuration and the central hexagon becomes aromatic., (© 2023 Wiley-VCH GmbH.)

Intrinsically stretchable polymer semiconductors are highly demanding for flexible electronics. However, it still remains challenging to achieve synergy between intrinsic stretchability and charge transport property properly for polymer semiconductors. In this paper, terpolymers are reported as intrinsically stretchable polymeric semiconductors with good ductility and high charge mobility simultaneously by incorporation of non-centrosymmetric spiro[cycloalkane-1,9'-fluorene] (spiro-fluorene) units into the backbone of diketopyrrolopyrrole (DPP) based conjugated polymers. The results reveal that these terpolymers show obviously high crack onset strains and their tensile moduli are remarkably reduced, by comparing with the parent DPP-based conjugated polymer without spiro-fluorene units. They exhibit simultaneously high charge mobilities (>1.0 cm 2 V -1 s -1 ) at 100% strain and even after repeated stretching and releasing cycles for 500 times under 50% strain. The terpolymer P2, in which cyclopropane is linked to the spiro-fluorene unit, is among the best reported intrinsically stretchable polymer semiconductors with record mobility up to 3.1 cm 2 V -1 s -1 at even 150% strain and 1.4 cm 2 V -1 s -1 after repeated stretching and releasing cycles for 1000 times., (© 2023 Wiley-VCH GmbH.)

A robust single-molecule light-emitting diode (SM-LED) with high color purity, linear polarization, and efficiency tunability is prepared by covalently integrating one fluorescent molecule into nanogapped graphene electrodes. Furthermore, single-molecule Förster resonance energy transfer from the electroluminescent center to different accepters is achieved through rational molecular engineering, enabling construction of a multicolor SM-LED. All these characterizations are accomplished in the photoelectrical integration system with high temporal/spatial/energy resolution, demonstrating the capability of the single-photon emission of SM-LEDs. The success in developing high-performance SM-LEDs inspires the development of the next generation of commercial display devices and promises a single-photon emitter for use in quantum computation and quantum communication., (© 2023 Wiley-VCH GmbH.)

We herein report a phosphoric-acid-substituted tetraphenylethene (T-P) capable of adapting its geometric configuration and biological activity to the microenvironment upon light irradiation for apoptosis modulation. Different from most ultraviolet-responsive isomerization, T-P undergoes cis-trans isomerization under visible light irradiation, which is biocompatible and thus photo-modulation is possible in living biosystems. By using alkaline phosphatase (ALP) and albumin as dual targets, T-P isomers display different protein binding selectivity, cancer-cell internalization efficiency and apoptosis-inducing ability. The proapoptotic activity was found to be kinetically controlled by the enzymatic reaction with ALP and regulated by co-existing albumin. Motivated by these findings, two-way modulation of proapoptotic effect and on-demand boosting anticancer efficacy were realized in vitro and in vivo using light and endogenous proteins as multiple non-invasive switching stimuli., (© 2022 Wiley-VCH GmbH.)

Herein, single-molecule conductance studies of TBT1-TBT6 which entails 1,4-dithienylbenzene as the backbone and SMe groups as the anchoring units, with the scanning tunneling microscope break junction (STM-BJ) technique, are reported. The molecular conductance of TBT1 with intramolecular O•••S noncovalent interactions is enhanced by about one order of magnitude in comparison to their analogue TBT2 (which contains alkyl instead of alkoxy chains). By replacing the methoxy groups in TBT1 with extending alkoxy chains in TBT3, TBT4, and TBT5, the molecular backbones become twisted and as a consequence the single-molecule conductance decreases gradually, showing that the intramolecular O•••S noncovalent interaction is influenced by the structural features of alkoxy chains. More importantly, the single-molecule conductance of TBT3, TBT4, and TBT5 can be boosted by increasing the electric field applied to the molecular junctions. Remarkably, the conductance of TBT3, TBT4, and TBT5 can be reversibly modulated due to the conformational changes between twisted and planar ones by varying the electric field. These results demonstrate that molecules with intramolecular O•••S noncovalent interactions have the potential for in situ control of the electrical properties of molecular-scale devices., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Molecular systems that can function as photoresists are essential for the fabrication of flexible electronics through all-photolithographic processes. Most of the reported molecular systems for photo-patterning of polymeric semiconductors contain binary or multi-components. In comparison, single component semiconducting photoresist is advantageous since it will circumvent the optimization of phase separation and ensure the patterned semiconducting thin films to be more uniform. In this paper, a single component semiconducting photoresist (PDPP4T-N 3 ) by incorporating azide groups into the branching alkyl chains of a diketopyrrolopyrrole-based conjugated polymer is reported. The results reveal that i) the azide groups make the side chains to be photo-cross-linkable; ii) uniform patterns with size as small as 5 µm form under mild UV irradiation (365 nm, 85 mW cm -2 ) at ambient conditions; iii) such photo-induced cross-linking does not affect the inter-chain packing; iv) benefiting from the single component feature, field-effect transistors (FETs) with the individual patterned thin films display satisfactorily uniform performances with average charge mobility of 0.61 ± 0.10 cm 2  V -1  s -1 and threshold voltage of 3.49 ± 1.43 V. These results offer a simple yet effective design strategy for high-performance single component semiconducting photoresists, which hold great potentials for flexible electronics processed by all-photolithography., (© 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Development of pure organic molecular materials with room temperature phosphorescence (RTP) and their applications for white emitters have received significant attentions recently. Herein, a D-π-A molecule (DMACPPY) which can realize white emitting under ambient conditions both in the crystal state and the doped-film state by combining RTP with two fluorescent emissions is reported. The white emission from the crystalline sample of DMACPPY consists fluorescence from S 2 (the second excited singlet state) and S 1 (the first excited singlet state) along with RTP from T 1 (the first excited triplet state), namely, SST-type white light. While, the white emission from the poly methyl methacrylate (PMMA) film doped with DMACPPY contains fluorescences from S 2 and S 1 , and RTP from T 2 (the second excited triplet state) rather than T 1 (STS type). DMACPPY cannot exhibit white spectrum within alternative crystalline state since inferior RTP intensity despite similar ternary emissions. The results demonstrate that the emissive properties for excited states of DMACPPY can be tuned by changing the aggregate state from crystalline to dispersion state in PMMA film. This new RTP emitter fulfills the talent for white emitting and achieves dual-mode white emissions, invisibly, expands the application range for pure organic and heavy atom-free RTP materials., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Photodynamic therapy (PDT) has emerged as an attractive alternative in cancer therapy, but therapeutic effects suffer from low photosensitizing efficiency and poor retention of photosensitizes in cancer cells. This paper reports the photosensitizers which show absorption and emission in the long-wavelength region and high photosensitizing efficiency can be formed in situ in cells from 4,6-dibromothieno[3,4-b]thiophene derivative (TT-5-P) after white light irradiation. The self-oligomerization of TT-5-P is uptaken in cells upon light irradiation-induced cell apoptosis simultaneously and efficiently. In addition, the formation of oligomers (TT-5-Ps) enhances the retention time in cells remarkably, which is advantageous for boosting the photodynamic therapy efficiency. Moreover, the selectivity toward tumor cells of TT-5-P can be improved obviously via the formation of complex of TT-5-P with albumin. This in situ photoinduced self-oligomerization strategy can be utilized to design effective biomaterials for long-term imaging and improved therapy., (© 2021 Wiley-VCH GmbH.)

A diazirine-based four-armed cross-linker (4CNN) with a tetrahedron geometry is presented for efficient patterning of polymeric semiconductors by photo-induced carbene insertion. After blending of 4CNN with no more than 3 % (w/w), photo-patterning of p-, n-, and ambipolar semiconducting polymers with side alkyl chains was achieved; regular patterns with size as small as 5 μm were prepared with appropriate photomasks after 365 nm irradiation for just 40 s. The interchain packing order and the thin film morphology were nearly unaltered after the cross-linking and the semiconducting properties of the patterned thin films were mostly retained. A complementary-like inverter with a gain value of 112 was constructed easily by two steps of photo-patterning of the p-type and n-type semiconducting polymers. The results show that 4CNN is a new generation of cross-linker for the photo-patterning of polymeric semiconductors for all-solution-processible flexible electronic devices., (© 2021 Wiley-VCH GmbH.)

Diketopyrrolopyrrole (DPP) as a building block has been intensively investigated for organic semiconductors and light emitting materials. The synthesis of N-aryl DPPs remains challenging. Herein, we firstly report a new easily handled synthetic method toward N-aryl DPPs through H-DPP with diaryliodonium salt in the presence of CuI, which shows broad reaction scope. Sixteen N-aryl DPPs, including phenyl, furan and thiophene as flanking aromatic groups, were synthesized with yields up to 78 %. These N-aryl DPPs are fluorescent in both solutions and solid states, with quantum yields up to 96 % and 40 %, respectively. Moreover, we show that the reaction between H-DPP and diaryliodonium salt can lead to π-expanded DPPs by using Pd(OAc) 2 as catalyst. Nine π-expanded DPPs were obtained in 27-61 % yields. These π-expanded DPPs exhibit good semiconducting properties with hole mobility of 0.71 cm 2  V -1  s -1 , demonstrating that they are useful building blocks for high performance organic semiconductors., (© 2021 Wiley-VCH GmbH.)

A systematic combination strategy is proposed for overcoming cisplatin resistance using near-infrared (NIR)-light-triggered hyperthermia. A new photothermal polymer DAP-F is complexed with a reduction-sensitive amphiphilic polymer P1 to form F-NPs with photothermal effect. Subsequently, to build the final nanosystem F-Pt-NPs, F-NPs are combined with Pt-NPs, which are obtained by encapsulating a Pt(IV) prodrug with P1. Mild hyperthermia (43 °C), generated from F-Pt-NPs induced by an 808 nm NIR laser, have various effects such as: i) enhancing the cellular membrane permeability to promote the uptake of drugs; ii) activating cisplatin by accelerating the glutathione consumption; iii) increasing the Pt-DNA adducts formation and possibly the formation of a portion of irreparable Pt-DNA interstrand crosslinks, thereby inhibiting the repair of DNA. In vitro, it is found that even on cisplatin-resistant A549DDP cells, the IC 50 of F-Pt-NPs (43 °C) is only 7.0 × 10 -6 m Pt mL -1 . In vivo, on a patient-derived xenograft model of multidrug resistant lung cancer, the efficacy of the F-Pt-NPs (43 °C) treatment group shows a tumor inhibition rate of 94%. Taken together, here, an important perspective of resolving cascade drug resistance with the assistance of mild hyperthermia triggered by NIR light is presented, which can be of great significance for clinic translation., (© 2021 Wiley-VCH GmbH.)

A new design strategy for photoresponsive semiconducting polymer with tri-stable semiconducting states is reported by simultaneous incorporation of tetra-ortho-methoxy-substituted azobenzene (mAzo) and arylazopyrazole (pAzo) in the side chains. The trans-to-cis transformations for mAzo and pAzo groups can sequentially occur within the polymer thin film after sequential 560 and 365 nm light irradiation. Remarkably, the trans-cis isomerization of mAzo and pAzo groups can modulate the thin film crystallinity. Accordingly, the performances of the resulting field-effect transistors (FETs) can be reversibly modulated, leading to tri-stable semiconducting states after sequential 560, 365, and 470 nm light irradiation. Therefore, the device performance can be logically controlled by light irradiation at three different wavelengths. In addition, with light irradiation and device current as the input and output signals, the three-value logic gate by using single FET device can be successfully mimicked., (© 2021 Wiley-VCH GmbH.)

The importance of mitochondria in tumorigenesis makes these organelles an ideal target for cancer therapy. In recent years, luminogens with the aggregation-induced emission (AIE) effect have been developed for mitochondrial targeting and cancer treatment. The induction of mitochondrial dysfunction can be an effective pathway of chemotherapy, photodynamic therapy, and combination therapy against cancer. This review focuses on recent progress in the field of AIE luminogens (AIEgens) for cancer theranostics based on mitochondrial targeting and dysfunction. AIEgens for cancer treatment, including chemotherapy, photodynamic therapy, and combination therapy, are summarized herein. Molecular design efforts toward mitochondrial targeting and mitochondria-damaging mechanisms are also discussed. Finally, we discuss the challenges and future directions of development for AIEgens in mitochondria-targeted cancer treatment., (© 2020 Wiley-VCH GmbH.)

Optically tunable field-effect transistors (FETs) with near infra-red (NIR) light show promising applications in various areas. Now, arylazopyrazole groups are incorporated in the side chains of a semiconducting donor-acceptor (D-A) polymer. The cis-trans interconversion of the arylazopyrazole can be controlled by 980 nm and 808 nm NIR light irradiation, by utilizing NaYF 4 :Yb,Tm upconversion nanoparticles and the photothermal effect of conjugated D-A polymers, respectively. This reversible transformation affects the interchain packing of the polymer thin film, which in turn reversibly tunes the semiconducting properties of the FETs by the successive 980 nm and 808 nm light irradiation. The resultant FETs display fast response to NIR light, good resistance to photofatigue, and stability in storage for up to 120 days. These unique features will be useful in future memory and bioelectronic wearable devices., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Tuning autophagy in a controlled manner could facilitate cancer therapy but it remains challenging. Pyridinium-substituted tetraphenylethylene salts (PTPE 1-3), able to target mitochondria and disrupt autophagy after forming complexes with albumin, are reported. Mitochondrion affinity and autophagy-inducing activity are improved by prolonging the length of alkyl chains in PTPE 1-3. PTPE 1-3 demonstrate proautophagic activity and a mitophagy blockage effect. Failure of autophagosome-lysosome fusion in downstream autophagy flux results in cancer cell death. Moreover, fast formation of complexes of PTPE 1-3 with albumin in blood can facilitate biomimetic delivery and deep tumor penetration. Efficient tumor accumulation and effective tumor suppression are successfully demonstrated with in vitro and in vivo studies. PTPE 1-3 salts exhibit dual functionality: they target and image mitochondria because of aggregation-induced emission effects and they are promising for cancer therapy., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Polycyclic aromatic hydrocarbons with hexagons/pentagons or hexagons/heptagons have been intensively investigated in recent years, but those with simultaneous presence of hexagons, pentagons and heptagons remain rare. In this paper, we report dicyclohepta[ijkl,uvwx]rubicene (DHR), a non-benzenoid isomer of dibenzo[bc,kl]coronene with two pentagons and two heptagons. We developed an efficient and scalable synthetic method for DHR by using Scholl reaction and dehydrogenation. Crystal structure of DHR shows that the benzenoid rings, two pentagons and two heptagons are coplanar. The bond lengths analysis and the ICSS(1)zz and LOL-π calculations indicate that the incorporation of two formal azulene moieties has an effect on the conjugated structure. The π-electrons of benzenoid and pentagon rings are more delocalized. Cyclic voltammetry studies indicate that DHR shows multiple oxidation and reduction potentials. Interestingly, DHR exhibits unusual S 0 to S 2 absorption and abnormal anti-Kasha S 2 to S 0 emission. Moreover, crystals of DHR exhibit semiconducting behaviour with hole mobility up to 0.082 cm 2  V -1  s -1 ., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The experimental investigation of intermolecular charge transport in π-conjugated materials is challenging. Herein, we describe the investigation of charge transport through intermolecular and intramolecular paths in single-molecule and single-stacking thiophene junctions by the mechanically controllable break junction (MCBJ) technique. We found that the ability for intermolecular charge transport through different single-stacking junctions was approximately independent of the molecular structure, which contrasts with the strong length dependence of conductance in single-molecule junctions with the same building blocks, and the dominant charge-transport path of molecules with two anchors transited from an intramolecular to an intermolecular path when the degree of conjugation increased. An increase in conjugation further led to higher binding probability owing to the variation in binding energies, as supported by DFT calculations., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Development of high-performance organic thermoelectric (TE) materials is of vital importance for flexible power generation and solid-cooling applications. Demonstrated here is the significant enhancement in TE performance of selenium-substituted diketopyrrolopyrrole (DPP) derivatives. Along with strong intermolecular interactions and high Hall mobilities of 1.0-2.3 cm 2  V -1  s -1 in doping-states for polymers, PDPPSe-12 exhibits a maximum power factor and ZT of up to 364 μW m -1  K -2 and 0.25, respectively. The performance is more than twice that of the sulfur-based DPP derivative and represents the highest value for p-type organic thermoelectric materials based on high-mobility polymers. These results reveal that selenium substitution can serve as a powerful strategy towards rationally designed thermoelectric polymers with state-of-the-art performances., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

It is shown that the semiconducting performance of field-effect transistors (FETs) with PDPP4T (poly(diketopyrrolopyrrole-quaterthiophene)) can be reversibly tuned by UV light irradiation and thermal heating after blending with the photochromic hexaarylbiimidazole compound (p-NO 2 -HABI). A photo-/thermal-responsive FET with a blend thin film of PDPP4T and p-NO 2 -HABI is successfully fabricated. The transfer characteristics are altered significantly with current enhanced up to 10 6 -fold at V G = 0 V after UV light irradiation. However, further heating results in the recovery of the transfer curve. This approach can be extended to other semiconducting polymers such as P3HT (poly(3-hexyl thiophene)), PBTTT (poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b] thiophene)) and PDPPDTT (poly(diketopyrrolopyrrole-dithienothiophene)). It is hypothesized that TPIRs (2,4,5-triphenylimidazolyl radicals) formed from p-NO 2 -HABI after UV light irradiation can interact with charge defects at the gate dielectric-semiconductor interface and those in the semiconducting layer to induce more hole carriers in the semiconducting channel. The application of the blend thin film of PDPP4T and p-NO 2 -HABI is further demonstrated to fabricate the photonically programmable and thermally erasable FET-based nonvolatile memory devices that are advantageous in terms of i) high ON/OFF current ratio, ii) nondestructive reading at low electrical bias, and iii) reasonably highly stable ON-state and OFF-state., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Recent decades have witnessed the rapid development of semiconducting polymers in terms of high charge mobilities and applications in transistors. Significant efforts have been made to develop various conjugated frameworks and linkers. However, studies are increasingly demonstrating that the side chains of semiconducting polymers can significantly affect interchain packing, thin film crystallinity, and thus semiconducting performance. Ways to modify the side alkyl chains to improve the interchain packing order and charge mobilities for conjugated polymers are first discussed. It is shown that modifying the branching chains by moving the branching points away from the backbones can boost the charge mobilities, which can also be improved through partially replacing branching chains with linear ones. Second, the effects of side chains with heteroatoms and functional groups are discussed. The siloxane-terminated side chains are utilized to enhance the semiconducting properties. The fluorinated alkyl chains are beneficial for improving both charge mobility and air stability. Incorporating H bonding group side chains can improve thin film crystallinities and boost charge mobilities. Notably, incorporating functional groups (e.g., glycol, tetrathiafulvalene, and thymine) into side chains can improve the selectivity of field-effect transistor (FET)-based sensors, while photochromic group containing side chains in conjugated polymers result in photoresponsive semiconductors and optically tunable FETs., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Conjugated molecules with low lying LUMO levels are demanding for the development of air stable n-type organic semiconductors. In this paper, we report a new A-D-A'-D-A conjugated molecule (DAPDCV) entailing diazapentalene (DAP) and dicyanovinylene groups as electron accepting units. Both theoretical and electrochemical studies manifest that the incorporation of DAP unit in the conjugated molecule can effectively lower the LUMO energy level. Accordingly, thin film of DAPDCV shows n-type semiconducting behavior with electron mobility up to 0.16 cm 2 ⋅V -1 ⋅s -1 after thermal annealing under N 2 atmosphere. Moreover, thin film of DAPDCV also shows stable n-type transporting property in air with mobility reaching 0.078 cm 2 ⋅V -1 ⋅s -1 ., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Photoresponsive molecular systems are essential for molecular optoelectronic devices, but most molecular building blocks are non-photoresponsive. Employed here is a photoinduced proton transfer (PIPT) strategy to control charge transport through single-molecule azulene junctions with visible light under ambient conditions, which leads to a reversible and controllable photoresponsive molecular device based on non-photoresponsive molecules and a photoacid. Also demonstrated is the application of PIPT in two single-molecule AND gate and OR gate devices with electrical signal as outputs., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Photooxidation under sunlight has potential in organic synthesis, bacterial killing, and organic waste treatment. Photosensitizers (PSs) can play an important role in this process. High 1 O 2 generation efficiency and excellent photostability under sunlight, as well as easy recyclability are ideal properties for PSs, but are not easy to achieve simultaneously. Herein, a pure organic porous conjugated polymer PS, CPTF, shows great photostability, large specific surface area, and high 1 O 2 generation efficiency under sunlight for photooxidation. For the oxidation of aromatic aldehyde to aromatic acid, the PS catalyst shows excellent recyclability, and enables solvent-free reactions in high yields both under direct sunlight and simulated AM 1.5G irradiation. In addition, the successful application of CPTF as an antibacterial agent and organic waste decomposition under simulated AM 1.5G irradiation indicates the potential of CPTF in sunlight-induced waste water treatment., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Development of facile and economic approaches for assembling organic semiconductors into more ordered structures toward high charge mobilities is highly demanding for the fabrication of organic circuits. Here a simple and facile approach is reported to prepare conjugated polymer thin films with improved crystallinities and charge mobilities by self-assembling semiconducting polymers on water. The formation of polymer thin films with more ordered structures is attributed to coffee ring effect induced by solvent-evaporation on water, and the hydrophobic nature of conjugated polymers that forces the polymer chains to pack densely and orderly on water surface. This approach is applicable to typical semiconducting polymers, and charge mobilities of their thin films are boosted remarkably. Finally, this new method can be utilized to easily fabricate the array of field-effect transistors with high charge mobilities in an economic way.

Three dibenzothiophene-S,S-dioxide-based alternating copolymers were synthesized by facile Suzuki polymerization for visible light-responsive hydrogen production from water (> 420 nm). Without addition of any cocatalyst, FluPh2-SO showed a photocatalytic efficiency of 3.48 mmol h -1 g- 1 , while a larger hydrogen evolution rate (HER) of 4.74 mmol h -1 g -1 was achieved for Py-SO, which was ascribed to the improved coplanarity of the polymer that facilitated both intermolecular packing and charge transport. To minimize the possible steric hindrance of FluPh2-SO by replacing 9,9'-diphenylfluorene with fluorene, Flu-SO exhibited a more red-shifted absorption than FluPh2-SO and yielded the highest HER of 5.04 mmol h -1 g -1 . This work highlights the potential of dibenzothiophene-S,S-dioxide as a versatile building block and the rational design strategy for achieving high photocatalytic efficiency., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The immobilization of fluorescent photoinduced electron transfer (PET) switches/sensors into solid state, which usually cannot maintain their identical properties in solution, has remained a big challenge. Herein, a water-stable anthracene and maleimide appended zirconium-based-metal-organic framework (Zr-MOF; UiO-68-An/Ma) is reported. Unlike the regular intramolecular "fluorophore-spacer-receptor" format, the separated immobilization of fluorescent (anthracene) and acceptor (maleimide) groups into the framework of a multivariate MOF can also favor a pseudo-intramolecular fluorescent PET process, resulting in UiO-68-An/Ma with very weak fluorescence. Interestingly, after Diels-Alder reaction or thiol-ene reaction of maleimide groups, the pseudo-intramolecular fluorescent PET process in UiO-68-An/Ma fails and the solid-state fluorescence of the crystals is recovered. In addition, UiO-68-An/Ma shows an interesting application as solid-state fluorescent turn-on sensor for biothiols, with the naked eye response at a low concentration of 50 µmol L -1 within 5 min. This study represents a general strategy to enable the efficient tuning of fluorescent PET switches/sensors in solid state, and considering the fluorescence of the PET-based MOFs can be restored after addition of analyte/target species, this research will definitely inspire to construct stimuli-responsive fluorescent MOFs for interesting applications (e.g., logic gate) in future., (© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Singlet fission (SF), in which one singlet exciton (S 1 ) splits into two triplets (T 1 ) on adjacent molecules through a correlated triplet-pair 1 (TT) state, requires precise but difficult tuning of exciton energetics and intermolecular electronic couplings in the solid state. Antiaromatic 4nπ dibenzopentalenes (DPs) are demonstrated as a new class of single-chromophore-based intramolecular SF materials that exhibit an optically allowed S 2 state with E(S 2 )>2×E(T 1 ) and an optically forbidden S 1 state. Ultrafast population transfer from a high-lying S 2 state to a 1 (TT) state was observed in monomeric solution of styryl-substituted DP (SDP) on a sub-picosecond timescale. There is evidence of exciton diffusion (ED) of the 1 (TT) state to yield two individual long-lived triplets in SDP thin film. The overall triplet yield via intramolecular SF and subsequent triplet-pair diffusion can be as high as 142±10 % in thin film., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Apart from sensing and imaging, luminogens with aggregation-induced emission (AIE) are also interesting for photosensitizing. The photosensitizing behavior and bacteria-killing performance of a pyridinium-substituted tetraphenylethylene with an alkyne group (TPE-A-Py + ) is reported herein. Interestingly, TPE-A-Py + exhibits higher photosensitizing efficiency than TPE-Py + (without alkyne group) when I - was used as a counteranion. This is well explained by the fact that the ΔΕ ST between the excited singlet state (S 1 ) and triplet state (T 1 ) was lower for TPE-A-Py + than for TPE-Py + , according to theoretical calculations. Moreover, replacement of I - with other anions (PF 6 - , N(SO 2 CF 3 ) 2 - and BPh 4 - ) led to a decrease of photosensitizing efficiency for TPE-A-Py + . Notably, TPE-A-Py + could be used as an efficient photosensitizer to photo-inactivate ampicillin-resistant (amp r ) E. coli at low concentration under white-light irradiation very quickly., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Solid state emissive materials with high quantum yields and tunable emissions are desirable for various applications. A new TPE derivative (1) with two carbazole moieties and two cyano groups is reported, which shows typical aggregation induced emission behavior. Four crystals 1a, 1b, 1c, and 1d are obtained after crystallization from N,N-dimethylformamid (DMF), trichloromethane (CHCl 3 ), tetrahydrofuran (THF), and dichloromethane (CH 2 Cl 2 ), respectively. Crystal structural analyses reveal that (i) molecules of 1 co-crystallize with DMF, CHCl 3 , THF, and CH 2 Cl 2 in 1a, 1b, 1c, and 1d, respectively, and (ii) conformations of 1 are different within 1a, 1b, 1c, and 1d, and compound 1 within crystal 1a adopts the most twisting conformation. Crystalline solids 1a, 1b, 1c, and 1d exhibit high emission quantum yields up to 0.65, but their emission colors are varied from blue to green. In comparison, the amorphous solid of 1 is yellow-emissive with emission maximum at 542 nm. Moreover, the blue- or green-emissive crystalline solids and the yellow-emissive amorphous solid can be inter-converted by the grinding of crystalline solids and exposure of the amorphous solid to vapors of appropriate solvents. It is also demonstrated that microrods of 1a, 1b, and 1d show typical optical waveguiding behavior., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The fluorescence detection of nitroreductase (NTR) and evaluation of the hypoxia status of tumor cells are vital, not only for clinical diagnoses and therapy, but also for biomedical research. Herein, we report the synthesis and application of a new fluorometric "turn-on" probe for the detection of NTR (TPE-NO 2 ) that takes advantage of the aggregation-induced emission of tetraphenylethylene. TPE-NO 2 can detect NTR at concentrations as low as 5 ng mL -1 in aqueous solution. The detection mechanism relied on the aggregation and deaggregation of tetraphenylethylene molecules. Moreover, this fluorescent probe can be used to monitor the hypoxia status of tumor cells through the detection of endogenous NTR., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A comprehensive investigation into the spectral properties and excitation energy transfer in di- or tribranched dithienyldiketopyrrolopyrrole (DPP) molecules with meta-substituted benzene as a central core (TADPP2-TT and TADPP3), by means of steady-state and transient measurements and quantum chemical calculations, is reported. Excitation in the meta-substituted chromophores is localized on one of the DPP units in the branching molecules owing to the disruption of conjugation by meta substitution for both TADPP2-TT and TADPP3. Weak electronic couplings result from the long distance between the DPP chromophores and the steric effects from the attached side chains on DPP. The attachment of the acetylene linker in each branch, which has a very low twisting barrier, could also play an important role in reducing the interaction between DPP chromophores. The dynamics of the excited states show that excitation energy transfer occurs on the picosecond scale, which is attributed to the incoherent hopping mechanism., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Molecular materials with concomitant light-emissive and semiconducting properties have received increasing attention in recent years. Such dual functional materials ensure the development of multifunctional devices (e.g., organic light-emitting transistors) and the emergence of new technologies. However, owing to the fact that intermolecular interactions and dense packing have opposite effects on photoluminescence and charge-carrier mobility, it is still rather challenging to rationally design high-performance molecular materials that exhibit both semiconducting and light-emissive properties. In fact, only a limited number of such dual functional materials are available, and most of their performances need to be further improved. In this concept article we discuss the design strategies and perspectives of this challenging area with the introduction of representative examples of such dual functional materials reported in recent years., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We studied charge transport through core-substituted naphthalenediimide (NDI) single-molecule junctions using the electrochemical STM-based break-junction technique in combination with DFT calculations. Conductance switching among three well-defined states was demonstrated by electrochemically controlling the redox state of the pendent diimide unit of the molecule in an ionic liquid. The electrical conductances of the dianion and neutral states differ by more than one order of magnitude. The potential-dependence of the charge-transport characteristics of the NDI molecules was confirmed by DFT calculations, which account for electrochemical double-layer effects on the conductance of the NDI junctions. This study suggests that integration of a pendant redox unit with strong coupling to a molecular backbone enables the tuning of charge transport through single-molecule devices by controlling their redox states., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this paper seven salts of pyridinium-substituted tetraphenylethylene with different anions are reported. They show typical aggregation-induced emission. Crystal structures of three of the salts with (CF(3)SO(2))(2) N(-), CF(3) SO(3)(-), and SbF(6)(-) as the respective counter anions, are determined. The emission behavior of their amorphous and crystalline solids is investigated. Both amorphous and crystalline solids, except for the one with I(-), are highly emissive. Certain amorphous solids are red-emissive with almost the same quantum yields and fluorescence life-times. However, some crystalline solids are found to show different emission colors varying from green to yellow. Thus, their emission colors can be tuned by the counter anions. Furthermore, certain crystalline solids are highly emissive compared to the respective amorphous solids. Such solid-state emission behavior of these pyridinium-substituted tetraphenylethylene salts is interpreted on the basis of their crystal structures. In addition, optical waveguiding behavior of fabricated microrods is presented., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report a method for the rapid and efficient identification of bacteria making use of five probes having fluorescent characteristics (F-array) and subsequent statistical analysis. Eight kinds of bacteria, including normal and multidrug-resistant bacteria, are differentiated successfully. Our easy-to-perform and time-saving method consists of mixing bacteria and probes, recording fluorescent intensity data by automated flow cytometry, and statistical analysis. No washing steps are required in order to identify the different bacteria simultaneously., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two-dimensional covalent organic frameworks (2D COFs) provide a unique platform for the molecular design of electronic and optoelectronic materials. Here, the synthesis and characterization of an electroactive COF containing the well-known tetrathiafulvalene (TTF) unit is reported. The TTF-COF crystallizes into 2D sheets with an eclipsed AA stacking motif, and shows high thermal stability and permanent porosity. The presence of TTF units endows the TTF-COF with electron-donating ability, which is characterized by cyclic voltammetry. In addition, the open frameworks of TTF-COF are amenable to doping with electron acceptors (e.g., iodine), and the conductivity of TTF-COF bulk samples can be improved by doping. Our results open up a reliable route for the preparation of well-ordered conjugated TTF polymers, which hold great potential for applications in fields from molecular electronics to energy storage., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

New arylacetylene-substituted naphthalene diimides (NDIs) 1-6, with both light-emitting and semiconducting functions, are reported. Among them, the crystal structure of 1 was determined. On the basis of their reduction potentials and thin-film absorption spectra, the HOMO/LUMO energies of these modified NDIs were estimated. The results reveal that their HOMO/LUMO energies are slightly affected by the flanking aryl groups. The emission colors of these NDIs vary from green to red, and interestingly, they show aggregation-induced emission enhancement behavior with fluorescence quantum yields reaching 9.86% in the solid state. Microrods of 1, 3, and 5 show typical optical wave-guiding behavior with relatively low optical-loss coefficients. Organic field-effect transistors with thin films of these NDIs were fabricated with conventional techniques. The results indicate that thin films of 2, 4, and 6, with long and branched alkyl chains, show air-stable n-type semiconducting properties with electron mobilities of up to 0.035 cm(2) V(-1) s(-1) after thermal annealing, whereas 1, 3, and 5, with short alkyl chains, behave as n-type semiconductors under a nitrogen atmosphere with electron mobilities of up to 0.075 cm(2) V(-1) s(-1) after thermal annealing., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Due to their high electron affinities, chemical and thermal stabilities, π-conjugated molecules with imide/amide frameworks have received considerable attentions as promising candidates for high-performance optoelectronic materials, particularly for organic semiconductors with high carrier mobilities. The purpose of this Research News is to give an overview of recent advances in development of high performance imide/amide based organic semiconductors for field-effect transistors. It covers naphthalene diimide-, perylene diimide- and amide-based conjugated molecules and polymers for organic semiconductors., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)