Electrochemical actuators directly converting electrical energy to mechanical energy are critically important for artificial intelligence. However, their energy transduction efficiency is always lower than 1.0% because electrode materials lack active units in microstructure, and their assembly systems can hardly express the intrinsic properties. Here, we report a molecular-scale active graphdiyne-based electrochemical actuator with a high electro-mechanical transduction efficiency of up to 6.03%, exceeding that of the best-known piezoelectric ceramic, shape memory alloy and electroactive polymer reported before, and its energy density (11.5 kJ m−3) is comparable to that of mammalian skeletal muscle (~8 kJ m−3). Meanwhile, the actuator remains responsive at frequencies from 0.1 to 30 Hz with excellent cycling stability over 100,000 cycles. Furthermore, we verify the alkene–alkyne complex transition effect responsible for the high performance through in situ sum frequency generation spectroscopy. This discovery sheds light on our understanding of actuation mechanisms and will accelerate development of smart actuators.

In the interaction of PVP with Pt nanoparticles <7 nm in size, charge transfer is from carbonyl groups in PVP to Pt nanoparticles, whereas in the interaction of PVP with bulk Pt or Pt nanoparticles >25 nm in size, charge transfer is from Pt metal to the polymer side chain of PVP. There exists a critical nanoparticle size between 7 and 25 nm that would lead to a switch in the electron donor-acceptor property.

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With a carbazole moiety as the electron donor and a phosphine-oxide moiety as the electron acceptor, two novel star-shaped bipolar hosts, 4,4 0 ,4 00 -tri(N-carbazolyl)triphenylphosphine oxide (TCTP) and 3,6bis(diphenylphosphoryl)-9-(4 0 -(diphenylphosphoryl)phenyl)carbazole (TPCz), have been designed and synthesized. Their topology structure differences are that the phosphine-oxide moiety is located in the molecular centre and the periphery for TCTP and TPCz, respectively. The star-shaped architecture imparts them with high decomposition temperatures (T d : 497 C for TCTP and 506 C for TPCz) and results in the formation of a stable amorphous glassy state (T g : 163 C for TCTP and 143 C for TPCz), while the phosphine oxide linkage ensures the disrupted conjugation and the high triplet energy (>3.0 eV). In addition, both TCTP and TPCz possess a bipolar transporting capability. However, TCTP mostly transports holes and TPCz primarily conducts electrons. On the basis of appropriate device configurations, high performance blue electrophosphorescent devices with comparable efficiency (35.0-36.4 cd A À1 , 15.9-16.7%) have been realized using TCTP and TPCz as the host for the blue phosphor, respectively. Compared with the unipolar host, 4,4 0 ,4 00 -tri(N-carbazolyl)triphenylamine (TCTA, 15.9 cd A À1 , 7.8%), the efficiency is improved by more than two-fold. As far as the obtained state-of-the-art performance is concerned, we think that these novel materials should provide an avenue for the design of amorphous bipolar hosts with high triplet energy used for blue PhOLEDs on a star-shaped scaffold.

Bimetallic NiMo carbide supported on SiO2 has been synthesized by means of a temperature-programmed reaction. Characterization was performed by elemental analysis, Brunauer−Emmett−Teller (BET) surface area analysis, temperature-programmed reduction (H2−TPR), temperature-programmed oxidation (TPO), temperature-programmed desorption of NH3 (NH3−TPD), and X-ray diffraction (XRD). Elemental analysis and TPO characterization indicated that carbon was successfully introduced into the lattice of NiMo carbide by a temperature-programmed reaction with a mixture of H2 and CH4. Ethyl benzoate was used as a model molecule to investigate the hydrodeoxygenation (HDO) activities of NiMo carbide. As a comparison, HDO reactions of ethyl benzoate were also investigated over Mo carbide as well as CoMo sulfide. The results indicated that NiMo carbide was the most stable catalyst for HDO among the samples. On the basis of the hydrodeoxygenation (HDO) evaluation of ethyl benzoate and characterization of passivated and used NiMo carbide, it can be deduced that the changes of catalytic activity of NiMo carbide, during HDO reactions, may be ascribed to oxygen accumulation as well as coke deposition on the surface of the catalyst. HDO reactions of acetone and acetaldehyde were also investigated over NiMo carbide. The results indicated that NiMo carbide was a highly active and stable catalyst for HDO of acetone and acetaldehyde.

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An electroactive room‐temperature phosphorescence (RTP) polymer has been demonstrated based on a characteristic donor‐oxygen‐acceptor geometry. Compared with the donor–acceptor reference, the inserted oxygen atom between donor and acceptor can not only decrease hole‐electron orbital overlap to suppress the charge transfer fluorescence, but also strengthen spin‐orbital coupling effect to facilitate the intersystem crossing and subsequent phosphorescence channels. As a result, a significant RTP is observed in solid states under photo excitation. Most noticeably, the corresponding polymer light‐emitting diodes (PLEDs) reveal a dominant electrophosphorescence with a record‐high external quantum efficiency of 9.7 %. The performance goes well beyond the 5 % theoretical limit for typical fluors, opening a new door to the development of pure organic RTP polymers towards efficient PLEDs.