Utilization of renewable solar energy is crucial for addressing the global energy and environmental concerns and achieving sustainable development in our society. In this regard, photocatalytic water splitting has attracted significant interest as a cost-effective means to convert sustainable solar energy into valuable chemicals.
　　However, efficiency is sensitive to reaction conditions and experimental setup, it is difficult to compare the results obtained by different research groups or provide a reliable guide for large-scale implementation. Due to the lack of testing standards, it is difficult to compare the results obtained by different research groups or provide a reliable guide for large-scale implementation.
　　Recently, a research team led by Prof. LI Can and Prof. LI Rengui from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in collaboration with Prof. Kazunari Domen from The University of Tokyo, Prof. Lianzhou Wang from The University of Queensland, Prof. Kazuhiro Sayama from the National Institution of Advanced Industrial Science and Technology, and Prof. Gang Liu from the Institute of Metal Research, CAS, initiated the establishment of international efficiency accreditation and testing protocols for particulate photocatalysts toward solar fuel production.
　　Efficiency accreditation and testing protocols for particulate photocatalysts toward solar fuel production (Image by LI Rengui)
　　Their perspective, published in Joule, was expected to serve as a useful guide for developing a well-recognized testing standard and for further promoting research advances in the field of photocatalytic solar energy conversion.
　　The researchers discussed the protocols for the reliable determination of the efficiency of the overall photocatalytic water splitting reaction based on particulate photocatalysts.
　　They also proposed to establish accreditation research laboratories for efficiency certification toward the launch of a figure of merit - a "Best research photocatalyst efficiencies" chart.
　　This initiative would provide an important platform for establishing standard testing protocols for photocatalytic water splitting and for improving the solar-to-hydrogen conversion efficiency in practical applications.
　　This work was supported by the National Natural Science Foundation of China. (Text by LI Rengui)

　　In conventional solar cells, the excessive energy of carriers above the band gap of a semiconductor is lost in the form of heat due to rapid cooling of hot carriers via emission of phonons. This is a major reason for Shockley–Queisser limit of solar cell efficiency.
　　Extraction the hot carrier to selective contacts has the potential to boost power conversion efficiency of solar cells to as high as 66%. The challenge in efficient hot carrier extraction is that intraband cooling of hot carriers usually occurs in a sub-picosecond timescale.
　　A research group led by Prof. WU Kaifeng from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) recently observed hot electrons as long-lived as more than 300 picoseconds in electron-doped (n-doped) colloidal CdSe quantum dots.
　　This study was published in Nat. Commun. on Jan. 22.
　　Carrier-carrier, carrier-phonon and spin-spin interactions in doped quantum dots result in long-lived hot electrons (Image by WANG Junhui)
　　For lightly-doped dots they observed a slow 1Pe hot electron relaxation (~10 picosecond) resulting from a Pauli spin blockade of the preoccupying 1Se electron. For heavily-doped dots, a large number of electrons residing in the surface states introduced picosecond Auger recombination which annihilated the valance band hole. Thus the researchers could observe 300-picosecond-long hot electrons as a manifestation of a phonon bottleneck effect. This decreased the hot electron energy loss rate to a level of sub-meV per picosecond from a usual level of 1 eV per picosecond.
　　These results offered exciting opportunities of hot electron harvesting by exploiting carrier-carrier, carrier-phonon and spin-spin interactions in doped quantum dots.
　　"The observation of long-lived hot electrons in QDs light on the utilization of long-lived hot electrons for high-efficiency photovoltaics and photocatalysis," said Prof. WU.
　　This work was supported by the Ministry of Science and Technology of China, the Chinese Academy of Sciences, the National Natural Science Foundation of China and the LiaoNing Revitalization Talents Program. (Text by WANG Junhui)

　　Studying the creation and evolution of sulfur-containing compounds in outer space is essential for understanding interstellar chemistry. CS2 is believed to be the most important molecule in comet nuclei, interstellar dust, or ice cores. It could produce CS and S2 fragments after photodissociation.
　　The International Ultraviolet Explorer satellite only observed the emission spectra of CS and S2, not that of CS2. The photodissociation mechanism of CS2 molecules remains unclear, and S2 fragments have not been experimentally observed before.
　　Recently, a team led by Prof. YUAN Kaijun from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS), in cooperation with Prof. WANG Xing'an's group from the University of Science and Technology of China, observed the C+S2 product channel from CS2 photodissociation for the first time using a home-made Time-Sliced Velocity Map Ion Imaging (TS-VMI) experimental setup based on the Dalian Coherent Light Source (DCLS).
　　Researchers Directly Observed the C + S2 Channel in CS2 Photodissociation (Image by LI Zhenxing)
　　This study, published in Journal of Physical Chemistry Letters on January 11, provided direct experimental evidence for the origin of the interstellar medium S2 fragments observed previously.
　　The researchers investigated the two-photon ultraviolet (UV) and one-photon vacuum ultraviolet (VUV) photodissociation dynamics of CS2 molecules via the VUV free-electron laser (FEL) at DCLS.
　　They directly observed the C+S2 product channel from CS2 photodissociation and obtained images of the electronically ground/excited states of S2 products with vibrational excitation. The electronically-excited states of the central atom of the CS2 molecule played an important role in the isomerization and photodissociation processes.
　　This research demonstrated that interstellar medium S2 fragments could be directly generated from CS2 photodissociation.
　　"Given the similarity of OCS studied in our previous works and CS2 in this work, we believe that the central-atom elimination channel is more general than expected in the photodissociation of triatomic molecules," stated Prof YUAN.
　　This work was supported by the Chemical Dynamics Research Center, the National Natural Science Foundation of China, and the Key Technology Team of CAS. (Text by LI Zhenxing)

　　In recent years, lead-free halide perovskite nanocrystals have been drawn more and more attention due to their low toxicity, high stability and chemical diversity.
　　It is important to reveal the carrier dynamics of the novel lead-free perovskite nanocrystals and to apply them effectively in the field of optoelectronic devices.
　　A research group led by Prof. HAN Keli from the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences reported the luminescence enhancement mechanism of a series of new lead-free quadruple halide perovskite nanocrystals, and prepared high-performance photodetectors.
　　This study was published in Adv. Mater. on January 25.
　　Efficient luminescent halide quadruple‐perovskite nanocrystals via trap‐engineering for highly sensitive photodetectors (Image by YANG Bin and BAI Tianxin)
　　The researchers reported for the first time a series of quadruple perovskite colloidal nanocrystals with ordered vacancies. By alloying Cs4MnBi2Cl12 nanocrystals, the fluorescence quantum yield could be increased by nearly 100 times.
　　Carrier ultrafast dynamics studies found that in the quadruple perovskite nanocrystals, free excitons were rapidly self-trapped as "self-trapped excitons", and a self-trapped exciton-assisted donor-acceptor (Mn2+) occured energy transfer process. Alloying could eliminate the ultra-fast defect state trapping process that competed with energy transfer, and increased the crystallinity of the nanocrystals, thereby improving the luminous efficiency.
　　Based on the alloyed quadruple perovskite nanocrystals with high crystallinity and long carrier lifetime, the researchers prepared a photodetector, which had ultra-high responsivity. The sensitivity was much higher than the previously reported photodetectors based on lead-free perovskite nanocrystals.
　　This work shows that the quadruple perovskite type nanocrystal opens up new possibilities for photovoltaic applications.
　　This work was supported by the National Natural Science Foundation of China. (Text by YANG Bin and BAI Tianxin)

　　Metal-chalcogen batteries (MCBs) are promising alternatives to the commonly used lithium-ion batteries due to their remarkable capacities as well as cheaper and more versatile electrodes.
　　Nevertheless, the rational design and controllable synthesis of electrode materials is still challenge.
　　Recently, Prof. LIU Jian's group and Prof. WU zhongshuai's group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in cooperation with Prof. LIANG Ji from Tianjin University, reviewed the application of nanoreactor for Metal-chalcogen batteries.
　　This work was published in Energy Environmental Science on Jan. 7.
　　Various nanoreactor designs for application as electrode material in MCBs and their most attractive functions (Image by Haodong Shi and Yash Boyjoo)
　　The essential functions of MCB electrodes include electrical conduction, cathode species encapsulation, intermediate species immobilization, cathode redox reaction acceleration and anode species stabilization.
　　Design of nanoreactors for MCBs has been proven as a highly feasible strategy for integrating some or all these features into an individual electrode material, to be used in these batteries.
　　"We introduced the concept and features of nanoreactors, and the major synthetic strategies for constructing nanoreactors with different morphologies and dimensions," said Prof. LIU.
　　Moreover, the researchers discussed the main functions of MCBs and how they could be imparted upon the electrode nanostructures via nanoreactor design and engineering. They also summarized the examples of typical nanoreactors for applications in MCBs and discussed the perspectives and future directions.
　　This study was supported Liaoning Natural Science Foundation, LiaoNing Revitalization Talents Program, Dalian National Laboratory for Clean Energy (DNL), and DNL Cooperation Fund. (Text by Haodong Shi)

　　Metal carbonyls play an important role in heterogeneous and homogeneous catalysis such as Fischer–Tropsch chemistry, hydroformylation, alcohol synthesis, and acetic acid synthesis.
　　Laser vaporization technique has been employed in generating and studying homoleptic metal carbonyl cations and anions in the gas phase, which serve as archetypical examples for demonstrating the metal–ligand bonding and the electron counting rules.
　　However, the spectroscopic characterization of neutral metal carbonyls in the gas phase is more challenging due to the difficulty of size selection.
　　A research team led by Prof. JIANG Ling from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with Prof. ZHOU Mingfei from Fudan University, identified a carbon-carbon coupling reaction in neutral transition metal carbonyls.
　　Their findings, published in The Journal of Physical Chemistry Letters, revealed that the C-O bond breaking and C-C bond formation proceeded efficiently in the reactions between laser vaporized titanium atoms and carbon monoxide. The study also highlighted a viable strategy for CO insertion for carbon-chain growth and higher alcohol synthesis.
　　Observation of Carbon–Carbon Coupling Reaction in Neutral Transition-Metal Carbonyls (Image by WANG Chong)
　　Based on the recently-developed infrared plus vacuum ultraviolet (IR+VUV) two-color ionization spectroscopy using a tunable vacuum ultraviolet free electron laser (VUV-FEL), the researchers synthesized and characterized a series of neutral titanium carbonyl complexes.
　　Bonding analysis indicated that the OTiCCO core structure could be described by the bonding interactions between a TiO+ cation in the doublet ground state and a doublet ground state of CCO-.
　　Theoretical calculations predicted that the Ti + nCO→OTiCCO(CO)n-2 reactions were both thermodynamically exothermic and kinetically facile in the gas phase.
　　The observed C-O bond cleavage and C-C bond formation was a viable strategy for CO insertion for carbon-chain growth and higher alcohol synthesis. (Text by WANG Chong)