Phenazine-based small molecules with well-defined structures and adjustable potentials may accurately disperse and support Pd nanoparticles, making them suitable as anode carrier materials for direct alcohol fuel cells. Herein, a series of carbazole-modified A-D-type phenazine-conjugated polycyclic aromatic hydrocarbons (PAHs) were conveniently obtained via the tandem cross-oxidative coupling/aromatization of readily available polyaromatic amines (PAAs) with p-phenylenediamine and subsequent coupling with diiodobiphenyl. These nitrogen-rich and insoluble organic small molecules with tunable properties can efficiently disperse and load Pd nanoparticles and can be used as anode carrier materials for ethanol oxidation. By adjustment of the electronic structure, stacking mode, and strength of the interaction between Pd and active sites of the carrier, the catalytic activity of the electrocatalysts can be regulated. Comparative studies unveil that there exist moderate Pd-N-C interactions in loosely stacked rod-shaped Pd/PPACz, resulting in the minimum Pd particle size of 2.6 ± 0.9 nm. The as-prepared electrochemical stable electrode exhibits good durability and the highest mass-specific current density of 3058 mA mg-1. Through the analysis of carrier morphology and Pd-N-C interactions, we attributed the high catalytic activity of Pd/PPACz to the effective dispersion of Pd on the carrier surface and the synergistic effect of the Pd and PPACz carriers. The results indicate that different PAH blocks have a direct effect on the morphology and electronic structure of the carrier material film. The coplanarity between the strong electron donor carbazole and the phenazine nucleus electron acceptor can directly change the electronic state of Pd, thereby affecting the adsorption behavior of Pd toward the intermediate products. Moreover, the nanoscale and effectively dispersed morphology of the carriers provide additional active centers. This study provides a new strategy for the rational design and rapid construction of organic small-molecule electrode materials for energy storage and conversion.

The popular planar carbazole‐based hole‐selective self‐assembled molecules (SAMs) for perovskite solar cells (PSCs) suffered from intrinsic instability toward electric potential, heat, and light illumination. To address this issue, herein, we report a kind of chiral helically shaped SAM, aza‐helicene phosphonic acid A5HPA, and A7HPA, featuring their self‐assembly attributed to the extended nonplanar π‐conjugated system of aza‐helicene with highly intrinsic stability toward thermal aging, light soaking, and electrical oxidation. Due to the increased torsion degree of the helicene backbone and the improved helical chiral molecular self‐consistency, P and M enantiomers of A7HPA molecules tend to stack in an alternating pattern similar to “gear mesh,” leading to reinforced intermolecular π–π interactions and conjugation effect to rigidify the hole transport layer. Consequently, the A7HPA‐based single‐junction wide bandgap PSC and perovskite‐silicon tandem solar cell exhibited impressive long‐term stability under both damp‐heat and light‐thermal synergetic stress tests and provided 23.41% and 33.06% (certified as 32.57%) power conversion efficiencies, respectively.

This article takes the representative ternary and quaternary polycyclic aromatic amines (PAAs) isomers such as phenanthamine and pyreneamine as examples, and uses the Clar's aromatic it-sextet rule combined with nucleus independent chemical shift (NICS) criteria and structural and electronic indices (such as HOMA, MCBO and MCI), to study their structure-reactivity relationship in electrochemical radical reactions based on the experimental results. By analyzing and discussing the changes in aromaticity and bond length of various ring systems in the structures of the substrates, radical intermediates, and products, as well as radical stability, we have gained a deeper understanding of the reaction mechanism and regioselectivity for construction of large it-conjugated frameworks of nitrogen fused helicenes and functional polymers through electrochemical tandem reactions of PAAs. In general, resonant structures containing more Clar's aromatic it-sextet in the structure have higher stability, which determines the reaction pathway and types of the product. In this study, Clar's rule, NICS criteria, HOMA, MCBO and MCI mutually supported and validated each other well, demonstrated that the combination of Clar's rule and NICS criteria may be a beneficial tool for analyzing and predicting the reactivity of PAH derivatives and the structure of complex polycyclic aromatic products, moreover, expanding their application to non-planar heteroatom doped helicenes beyond PAH compounds.

Buried defects at the interface between the wide-bandgap perovskite and the self-assembled monolayer (SAM) limit the performance of p-i-n solar cells, particularly in textured monolithic perovskite-silicon tandem solar cells. Here we reveal that uncontrolled perovskite crystallization dynamics on conventional SAMs drives the co-evolution of electronic defects and morphological degradation at the buried interface. This stems from structural and energetic incompatibility between the perovskite precursor solution and the SAM. To precisely control the perovskite crystallization, we develop a tailored SAM that mitigates defect formation and enhances interfacial electronic coupling. Integrated into a perovskite-silicon tandem solar cell, this approach enables a power conversion efficiency of 33.86% (certified as 33.59%) for a device with a 1-cm2 area and a power conversion efficiency of 29.25% (certified as 28.53%) for an area of 16 cm2. The tandem device demonstrates remarkable operational stability, retaining more than 90% of the initial power conversion efficiency after 2,000 h of operational under 1-sun illumination.

Experimental and theoretical study of the regioselectivity and mechanism of polycyclic aromatic amine (PAA) electrochemical oxidation is important for designing nitrogen doped large π-conjugated functional molecules. Herein, we used binary-, ternary-, and quaternary-fused PAAs as electro-oxidative reaction substrates to investigate the yield changes of carbazole and phenazine based aza-helicene other than oligomers, which were obtained through pyrrole and pyrazine annulation pathways. Combined with the restrained electrostatic potential (RESP) and steric hindrance factor analysis of the substrate, the electron spin density distribution of free radical resonance hybrid and the spin population analysis of the atoms in the structure of each free radical tautomer indicate that the degree of delocalized dispersion of N free radical and the resulting change in the spin density distribution of C free radical tautomers determine the reaction regioselectivity. The potential charge of the K-region, Bay-region, and L-region adjacent to the C(α)-C(β1) bond is higher than that of other regions within the molecule, and the charge in these high RESP regions tends to delocalize more strongly toward electron-deficient N free radicals. Thus, the activity of N-C(α)-C(β1) region is increased, which supports the proposed free radical addition and free radical coupling mechanism for the electro-oxidative reaction of PAA.

Developing high-performance adsorbents for energy-efficient separation of xylene isomers has important research and application value. Identification and separation of xylene isomers (PX, MX, and OX) at room temperature based on the different relative positions of two methyl groups on the benzene ring is an unprecedented attempt. Herein, 1-aminopyrene polymer (PAP) is designed and electro-synthesized composited with a supporting electrolyte as an adsorbent for the separation of xylene isomers using a multi-stage dispersed liquid-solid adsorption process at room temperature. Each -NH-pyrene-NH- unit can form a force field to identify and discriminate xylene isomer through pi-pi interaction combined with -CH3-NH- interactions of different strength, thereby achieving separation of PX, MX, and OX isomers by amplifying the slight differences in the adsorption capacity and diffusion rates. The density functional theory (DFT) simulations provide a more quantitative analysis of the adsorbate-adsorbent interactions to illustrate PX > MX > OX order of adsorption selectivity. This study may offer an alternative strategy for the precise designing of energy-efficient and adsorption-based separation materials.

Repeated tandem electro-oxidative C-C and C-N coupling and aromatization were employed for the efficient construction of aza[7]helicene (BA7) as a key intermediate and the targeted pyrazine-fused bis-aza[7]helicene (PBBA7) derivatives in 90.0-93.2% isolated yields under a controlled potential. The electrosynthetic protocol showed high selectivity and enabled rapid access to functionalized organic conjugated materials from readily available polycyclic aromatic amines. A synthetic mechanistic study along with an investigation of the photoelectrical properties and application of PBBA7-C16 as a potential hole-transporting material for perovskite solar cells were performed.

通过集成微流控流体操控、反应控制和电子控制3个系统,成功研制了模块化微流控芯片正电子发射计算机断层扫描(positron emission tomography,PET)显像剂合成仪.将不同结构的微流控芯片进行组合,实现富集、控温合成、分离、纯化等功能的模块化,以满足不同PET显像剂的合成制备要求.实验结果表明,用该仪器自动化合成18F-FDG显像剂仅需25 min,放射化学产率为48％～56％(未衰减校正,n>20),放射化学纯度高于98％,单次合成剂量为10～50 mCi,达到临床使用要求.

Ion migration, an intrinsic property that cannot be suppressed by device encapsulation, is of great importance to the long-term stability of perovskite solar cells. Herein, we synthesize a polyethylene glycol-modified fullerene (PCBHGE) and then incorporate it into perovskite absorber layers. It is found that PCBHGE can stabilize [PbI6](4-) octahedral frameworks by forming Lewis acid-base pairs. Decoupling the efficient defect passivation of the fullerene core, ion migration is suppressed significantly in the as-fabricated devices. As a result, our state-of-the-art device demonstrates a highest efficiency of 23.19%. Most importantly, the device with PCBHGE can retain 87% of its maximum efficiency after 206 days. Tracked at the maximum power point under a continuous bias, the device efficiency hardly decreases in the first 212 h with a UV filter and can retain 80% of its initial efficiency after the next 600 h under full spectrum illumination including UV light.

Chrysene is a readily available material for exploring new polycyclic aromatic hydrocarbons (PAHs). In this study, two chrysene based azahelicenes, nine-membered BA7 and ten-membered DA6, are constructed by intermolecular oxidative annulation of 6-aminochrysene and intramolecular annulation of N6 ,N12 -bis(1-chloronaphthalen-2-yl)chrysene-6,12-diamine, respectively. The hexylated BA7 and DA6 and their brominated products were undoubtedly characterized by single crystal XRD. Subsequent amination with bis(9-methyl-9H-carbazol-3-yl)amine (BMCA) electron donor afforded D-π-D-type semiconductors BA7-BMCA and DA6-BMCA with beneficial properties to act as hole transport materials for perovskite solar cell. Compared with 19.4 % champion power conversion efficiency (PCE) of BA7-BMCA based device, a higher PCE of 20.2 % for DA6-BMCA counterpart may be attributed to its S-shaped double helicene-like linker with extended π-conjugated system.

A thia[5]helicene based molecular semiconductor maintains π–π stacking, ensuring a large domain of molecular aggregates and a high hole mobility.

The superior role of helical pi-linkers is demonstrated for the design of donor-pi linker-donor typed molecular semiconductors in perovskite solar cells (PSCs). Flat N-annulated perylene (NP) and contorted aza[5]helicene (A5H) are side-functionalized with methoxyphenyl and end-capped with dimethoxydiphenylamine electron-donor to afford two small-molecule hole-transporters J3 and J4. For methoxyphenyl functionalized pi-linkers, intermolecular pi...pi interactions in planar NP exist more extensively than those in helical A5H. However, for the dimethoxydiphenylamine derived hole-transporters with high highest occupied molecular orbital energy levels, a part of the pi...pi interaction remains for J4 with A5H, while this desirable effect for charge transport is completely deprived for J3 with NP. Thus, the theoretically predicted hole mobility of J4 single-crystal is even over two times higher than that of J3 one. Because of the larger size of the molecular aggregate, the hole mobility of the spin-coated J4 thin film is also over three times as high as that of the J3 analog. Due to the reduced transport resistance and enhanced recombination resistance, PSCs with J4 exhibit a power conversion efficiency of 21.0% at standard air mass 1.5 global conditions, which is higher than that of 19.4% with J3 and that of 20.3% with spiro-OMeTAD control.

Maintaining persistent thin-film morphology under certain thermal stress is desirable for durable operation of multi-layer organic optoelectronic devices. We herein report a thioxanthenothioxanthene-centered hole-transporter (N-3,N-3,N-9,N-9-tetrakis(4-methoxyphenyl)thioxantheno [2,1,9,8- klmna]thioxanthene-3,9-diamine, TXTX-OMeDPA) characteristic of two-dimensional molecular stacking in a single crystal. TXTX-OMeDPA can be solution-processed into smooth thin films with suitable energy level and good hole mobility, allowing for the fabrication of perovskite solar cells with an impressive power conversion efficiency of 22.2% when measured under illumination of AM 1.5G sunlight. The remarkable morphological stability of TXTX-OMeDPA-based thin film ensures good stability for perovskite solar cells not only stored at 60 degrees C in the dark but also operated under equivalent full sunlight at 60 degrees C.

Triphenylamine (TPA) and binaphthyl (BINAP) have been widely used as building blocks in optoelectronics materials for their good electron donating and transport capability. However, TPA-bonded BINAP type of fluorescent probe towards Fe3+, a kind of important metal ion, has not been studied. Herein, a series of TPA-bonded BINAP D A-D type derivatives, 6,6-TB-1, 6,6-TB-2, 7,7-TB-1, 7,7-TB-2, and 7,7-OMeTB-1, was synthesized to investigate their fluorescence (FL) chemosensor properties and electronic effect on sensitivity. Results showed that these probes exhibited highly selective FL quenching toward Fe3+ in the presence of other common metal ions, and an enhanced sensitivity (limit of detection 1.7 x 10(-7) M) not inferior to that of other works, could be achieved by introducing electron-donating substituent into TPA group. Then, comprehensive studies, such as NMR, EPR, MALDI-TOF-MS, and XPS combined with Mulliken atomic charges analysis were performed to gain an insight into the probe's binding with Fe3+ to understand the detection mechanism. Compared with other works on TPA-based fluorescent probes ascribed to fluorescence resonance energy transfer (FRET) or charge transfer (CT) mechanism, we reveal the interaction between Fe3+ and N atom of TPA and the formation of probe-Fe3+ complex leading to FL quenching. This work provides a simple strategy for designing a cost-effective Fe3+ fluorescent probe based on a single binding site to target one specific analyte.

So far, the application of fullerene derivative support in electrocatalysis has been limited by fullerene’s low electronic conductivity and the difficulty in film morphology control. Although highly conductive (1.5 s m−1) fullerene ammonium iodide (PCBANI) had been demonstrated to be a potential support, the solid self-assembled film is not of benefit for metallic nanoparticle (NP) to exhibit catalytic activity. In this work, we found solvent engineering of pristine PCBANI aggregate could maintain stacked short-range assembly structure and porous morphology. Moreover, PCBANI film fabricated from the optimized DMSO/methanol could immobilize Pd NPs with a uniform size of around 4.8 ± 1.7 nm which was characterized by SEM, TEM, and SAED. The resulting Pd/PCBANI-1-coated electrode exhibits a mass-specific activity for Pd of 3361.0 mA mg−1 at a scan rate of 50 mV s−1 and good stability toward alcohol electrooxidation, which are both significantly higher than that of the Pd/PCBANI-2 fabricated from PCBANI’s acetic acid/methanol dispersion and commercial Pd/C (active carbon). To the best of our knowledge, Pd/PCBANI-1 exhibits almost the highest catalytic activity among the existing fullerene-based Pd nanocatalysts. The high performance of the as-fabricated catalyst is attributed to highly conductive and porous PCBANI support, good dispersibility of Pd NPs on support, and favorable mass transfer.

Halide ion's doping of fullerene core is crucial on the properties of highly conductive self-n-doped fullerene ammonium halides, which are a kind of promising electron transport material for photovoltaics. Herein, to understand their photoexcited electron transfer (ET) property, antimicrobial photodynamic inactivation (aPDI) activities of these materials were tested based on their unique electronic structure and bacterial electrokinesis. We observed that illuminated self-n-doped fullerene ammonium iodides (PCBANI and PCBDANI) could exhibit significant improvement of activity against two important plant pathogenic fungi, Sclerotinia sclerotiorurn and Fusarium graminearum as electron donor, compared with that in dark. Through comprehensive studies, such as aPDI activity, hyphal cell morphology, ultrafast transient absorption spectroscopy, solid state nuclear magnetic resonance (ssNMR), level of total cellular reactive oxygen species (ROS), we verified that not ROS but I radical's oxidative stress is responsible for the improved aPDI activity. Moreover, the photobiological activity of self-n-doped fullerene ammonium halides is dependent on the reducing capacity of halide anions. The ET rate from anion to an excited fullerene core decreased successively from I- to Br- and then Cl-, illustrating that the generation rate of I radical species was the fastest and consistent with the high activity of fullerene ammonium iodides. Remarkably, adding potassium iodide did not enhance PCBANI's antifungal activity. These results disclose that the unique electronic structure of iodide and fullerene core in self-n-doped PCBANI aggregates are critical for its aPDI activity. Consequently, we propose a possible dual-redox cycles mechanism involving photoexcited fullerene radical anions and I radical species in self-n-doped fullerene ammonium iodide aggregate to exhibit sustainable aPDI activity. This work reveals that halide ions play an equally important role as fullerene core in photoexcited ET property of self-n-doped fullerene ammonium halides.

Reduced graphene oxide/[6,6]-phenyl-C61-butyric acid trimethylaminoethyl ester iodide hybrid composites (RGO-PCBANI) were used to support Pd nanoparticle to fabricate Pd/RGO-PCBANI electrocatalysts on electrode. The morphology and structure of the RGO-PCBANI and Pd/RGO-PCBANI were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Furthermore, the electrocatalytic performance of Pd/RGO-PCBANI towards ethanol oxidation was evaluated by using electrochemical methods such as cyclic voltammetry and chronoamperometry. The results showed that the prepared RGO-PCBANI (6:1) support displayed good dispersibility and could immobilize Pd nanoparticle with 5. 2 nm average size. Moreover, the fabricated Pd/RGO-PCBANI(6:1) catalyst exhibited best catalyst activity and stability. The mass current density reached 1288. 8 mA/mg. The good catalytic performance is attributed to highly conductive PCBANI's spacer function in the RGO-PCBANI composite support.

Stable and highly conductive self-n-doped fullerene ammonium halides are promising optoelectronic materials. It is necessary to thoroughly understand their structure-function relationship and to develop their applications. Here, the assembly behaviors of the self-n-doped fullerene ammonium halides, as well as the functional areas in the well-developed 2D-3D lamellar structures in their ordered aggregates are systematically characterized using comprehensive methods. In the self-assembly, the solvation effect of DMSO promotes the flexibility of side-chains and drives the formation of fullerene ammonium halides into ordered bilayer structures. The conductivity-active area, which contains tightly packed halide anions sandwiched between fullerenes, provides good electron transfer property. Remarkably, residual DMSO in the side-chain area can induce aqueous Pd precursor into the highly conductive framework. After reduction, Pd nanoparticles are immobilized in the confined spaces within the conductive support. The resulting electrode can be used to electrooxidize ethanol. This study provides a facile solution strategy for the in situ fabrication of electrocatalysts on working electrodes, which can be applied in direct alcohol fuel cells.

A methanol-soluble diamine-modified fullerene derivative (denoted as PCBDANI) was applied as an efficient cathode buffer layer (CBL) in planar p-i-n perovskite solar cells (pero-SCs) based on the CH3NH3PbI3–x Cl x absorber. The device with PCBDANI single CBL exhibited significantly improved performance with a power conversion efficiency (PCE) of 15.45%, which is approximately 17% higher than that of the control device without the CBL. The dramatic improvement in PCE can be attributed to the formation of an interfacial dipole at the PCBM/Al interface originating from the amine functional group and the suppression of interfacial recombination by the PCBDANI interlayer. To further improve the PCE of pero-SCs, PCBDANI/LiF double CBLs were introduced between PCBM and the top Al electrode. An impressive PCE of 15.71% was achieved, which is somewhat higher than that of the devices with LiF or PCBDANI single CBL. Besides the PCE, the long-term stability of the device with PCBDANI/LiF double CBLs is also superior to that of the device with LiF single CBL.

Iodide–fullerene π interactions play decisive roles in n-doping and electron transport of fullerenes at the perovskite–PCBM interface in the devices of perovskite solar cells (Pero-SCs).