Latest ArticlesCharge-transfer (CT) stoichiometric cocrystals are promising choice of organic materials for unveiling the structure-property relationship. However, due to the contradiction between large CT degree required for strong NIR absorption and flexible molecular stacking, construction of stoichiomorphism-based cocystals with near-infrared (NIR) photothermal property remains challenging. Herein, the first example of stoichiomorphism-based photothermal cocrystals were accomplished through the adaptive assembly of 3,3′,5,5′-tetramethylbenzidine (TMB) donor and 1,2,4,5-tetracyanobenzene (TCNB) acceptor. The selective cocrystallization could be controlled by varying the donor-acceptor stoichiometries via a surfactant-assisted method, resulting in two cocrystals with 1:1 (T1C1) and 1:2 (T2C1) stoichiometries. The absorbance intensity of T1C1 at 808 nm was nearly twice that of T2C1, while the photothermal conversion efficiency (PCE) of the former was 60.3% ± 0.6%, approximately 80% of that for the latter (75.5% ± 2.6%), which might be caused by the different intermolecular interactions in distinct molecular stacking patterns. Notably, both excellent PCEs of stoichiometric cocrystals were attributed to the nonradiative transition process, including internal conversion and charge dissociation processes, as elucidated by femtosecond transient absorption spectroscopy measurements. Furthermore, T1C1 was used as an NIR heater for preparing agarose-based photothermal hydrogel, showing great potential for light-controlled in-situ gelation. This strategy of balancing the CT degree and molecular packing orientation not only uncovered the relationship between stoichiometric stacking and photothermal property, but also provided an opportunity to develop advanced organic optoelectronic materials.
Deep-blue emitter with high photoluminescence efficiency (PLQY) is highly desirable in ultra-high definition displays and white solid-state lightings. In this work, two deep-blue phenanthro[9,10]imidazole derivatives, PPIS and PPPIS, with hot exciton property are successfully developed. Compared to PPIS, the embedded phenyl bridge in PPPIS is able to effectively increase the overlap of frontier molecular orbitals. In consequence, PPPIS shows higher oscillator strength and significantly enhanced PLQY. PPPIS also achieves better electroluminescence performance in non-doped device, showing deep-blue emission with Commission International de l'Eclairage (CIE) coordinates of (0.153, 0.087) and the maximum external quantum efficiency (EQEmax) of 8.5% with minuscule efficiency roll-off. Meanwhile, when PPPIS serves as the host for phosphor PO-01, high-efficiency orange phosphorescent device is obtained with high EQEmax of 29.8% and negligible efficiency roll-off at 1000 cd/m2. Further, efficient single-emissive-layer white device is assembled via utilizing PPPIS as a blue emitter as well as the host for PO-01 simultaneously, providing warm-white emission with CIE coordinates of (0.429, 0.433) at 1000 cd/m2, the forward-viewing EQEmax of 27.2% and maximum power efficiency (PEmax) of 80.1 lm/W, respectively. Our studies can establish a viable design strategy for deep-blue emitters in high-performance non-doped blue OLEDs and hybrid WOLEDs.
Bioelectronics have gained substantial research attention owing to their potential applications in health monitoring and diagnose, and greatly promoted the development of biomedicine. Recently, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) hydrogels have arose as a promising candidate for the next-generation bioelectronic interface due to its high-conductivity, versatility, flexibility and biocompatibility. In this review, we highlight the recent advances of PEDOT:PSS hydrogels, including the gelation methods and modification strategies, and summarize their wide applications in different type of sensors and tissue engineering in detail. We expect that this work will provide valuable information regarding the functionalizations and applications of PEDOT:PSS hydrogels.
It has been widely recognized that hole transporting materials (HTMs) play a key role in the rapid progress of perovskite solar cells (PVSCs). However, common organic HTMs such as spiro-OMeTAD not only suffer from high synthetic costs, but also usually require the additional chemical doping process to improve their hole transport ability, which unfortunately induces the terrible stability issue. Therefore, it is urgent to develop low-cost dopant-free HTMs for efficient and stable PVSCs. In this work, we have successfully developed a new class of efficient dopant-free fluoranthene-based HTMs (TPF1–5) with quite low lab synthetic costs by combining donor-acceptor and branched structure designs. The detailed structure-property study revealed that tuning the twisted arms at different substitution sites would regulate the intermolecular interactions and film-forming ability, thereby significantly affecting the performance of the HTMs. By applying these HTMs in conventional PVSCs, the dopant-free TPF1-based devices not only achieved the best efficiency of 21.76%, which is comparable to that of the doped spiro-OMeTAD control devices, but also showed much better operational stability, which maintained over 87% of the initial efficiency under maximum power point tracking after 1038 h.
As a hydrolase, chymotrypsin (CHT) is involved in many physiological activities, and its abnormal activity is closely related to diabetes, pancreatic fibrosis, chronic pancreatitis and pancreatic cancer. In this work, an innovative long-wavelength emission fluorescent probe TCF-CHT was designed and synthesized for the high specificity detection of CHT, which utilized TCF-OH and a mimetic peptide substrate 4-bromobutyryl as chromogenic group and recognition group, respectively. TCF-CHT exhibited excellent selectivity and eye-catching sensitivity (8.91 ng/mL) towards CHT, "off-on" long-wavelength emission at 670 nm and large Stokes shift (140 nm). Furthermore, the successful fulfillment and perfect performance in imaging endogenous CHT in complex organisms (P815 cells, HepG2 cells, zebrafish and tumor-bearing mice) verified its potential as a powerful tool for the recognition of CHT in complicated biological environments.
A novel and readily available binaphthyl-based fluorescent probe (S)-1 was designed and synthesized. (S)-1 can be used to not only chemoselectively discriminate 3 basic amino acids out of common amino acids, but also enantioselectively recognize histidine. Encouragingly, enantioselective imaging of histidine in cells was achieved for the first time by the probe (S)-1. These performances endowed it potential application in the chiral analysis of basic amino acids in asymmetric synthesis and cell imaging for diagnosis of diseases caused by racemization of histidine. Nuclear magnetic resonance (NMR) and mass spectrometry investigations suggested that different reaction extent of (S)-1 with l/d-histidine and different product structures generated the observed enantioselective fluorescent response. The molecular structures and thermodynamic stability of the complexes, formed from (S)-1 + Zn2+ and enantiomers of histidine, were calculated by Gaussian 16 based on density functional theory (DFT) to validate the above action mechanism.
The development of efficient and stable bifunctional overall water-splitting is a crucial goal for clean and renewable energy, which is a challenging task. Herein, we report an Mn-incorporated RuO2 (Mn-RuO2) catalyst for highly efficient electrocatalytic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in acid and alkaline media. Benefiting from a more electrochemical active area with the incorporation of Mn, the Mn-RuO2 required an overpotential of 200 mV to attain a current density of 10 mA/cm2 for OER in acid. DFT result indicates that the doping of Mn into RuO2 can enhance the OER activity. An acidic overall water-splitting electrolyzer with good stability constructed by bifunctional Mn-RuO2 only requires a cell voltage of 1.50 V to afford 10 mA/cm2 and can operate stably for 50 h at 50 mA/cm2, which is better than the state-of-the-art Ru-based catalyst. Additionally, the Mn-RuO2 exhibits excellent HER and OER activity in alkaline media, and it shows superior activity and durability for overall water-splitting, only needing a cell voltage of 1.49 V to attain 10 mA/cm2. The present work provides an efficient approach to designing and constructing efficient Ru-based electrocatalysts for overall water-splitting.
The first example of sono-photocatalytic bond formation was reported. With both visible light and ultrasound wave as the energy, various 3-aminoquinoxalin-2(1H)-ones were efficiently obtained with good functional group tolerance in the absence of any additive or external photocatalyst. Compared with the conventional photocatalysis, sono-photocatalysis not only dramatically improved the reaction rates and yields, but also reduced energy consumption.