Ultrafast lasers play an important role in a variety of applications ranging from optical communications to medical diagnostics and industrial materials processing. Graphene and other two-dimensional（2D） noncarbon m...Ultrafast lasers play an important role in a variety of applications ranging from optical communications to medical diagnostics and industrial materials processing. Graphene and other two-dimensional（2D） noncarbon materials, including topological insulators（TIs）, transition metal dichalcogenides（TMDCs）, phosphorene, bismuthene, and antimonene, have witnessed a very fast development of both fundamental and practical aspects in ultrafast photonics since 2009. Their unique nonlinear optical properties enable them to be used as excellent saturable absorbers（SAs） that have fast responses and broadband operation, and can be easily integrated into lasers. Here, we catalog and review recent progress in the exploitation of these 2D noncarbon materials in this emerging field. The fabrication techniques, nonlinear optical properties, and device integration strategies of 2D noncarbon materials are first introduced with a comprehensive view. Then, various mode-locked/Q-switched lasers（e.g., fiber, solid-state, disk, and waveguide lasers） based on 2D noncarbon materials are reviewed. In addition, versatile soliton pulses generated from the mode-locked fiber lasers based on 2D noncarbon materials are also summarized. Finally, future challenges and perspectives of 2D materials-based lasers are addressed.展开更多
Electrochemical energy systems such as fuel cells and metal–air batteries can be used as clean power sources in the field of electric transportation and possess great potential in the reduction of various energy and ...Electrochemical energy systems such as fuel cells and metal–air batteries can be used as clean power sources in the field of electric transportation and possess great potential in the reduction of various energy and environmental issues.In these systems,the oxygen reduction reaction(ORR)at the cathode is the rate-determining factor for overall system performance,and up to now,platinum group metals supported on carbon materials,especially Pt,remain the highest performing and the most practical ORR electrocatalysts.However,corresponding carbonaceous catalyst supports are extremely susceptible to corrosion under electrochemical operation,and therefore,the extensive exploration of alternative stable materials for ORR electrocatalysts with both high electrochemical stability and catalytic performance is essential.Here,noncarbon materials with high corrosion resistance have been explored to substitute traditional carbon supports or even act directly as low-cost non-noble metal electrocatalysts,and based on this,this review will present a comprehensive overview and deep analysis of the recent progress in noncarbon materials,including metals,oxides,nitrides,carbides,sulfides,and so on.Overall,general attributes associated with noncarbon materials include high corrosion resistance,strong metal–support interaction,and impressive porous structure retention.However,major drawbacks include low electrical conductivity,insufficient chemical stability in acidic or alkaline media,and poor electrochemical stability at ORR electrode potentials.To overcome these challenges,this review will also summarize efficient strategies such as combining with highly conductive materials,introducing dopants and forming vacancies to result in promising electrocatalytic ORR performances.Finally,this review will propose possible research directions to facilitate future research and development toward the practical application of noncarbon-based ORR electrocatalysts.展开更多
Scientists are in the constant search of novel materials,or innovative applications of existing materials to solve problems we face in our everyday life.Although graphene,the two-dimensional（2D）form of carbon,has be...Scientists are in the constant search of novel materials,or innovative applications of existing materials to solve problems we face in our everyday life.Although graphene,the two-dimensional（2D）form of carbon,has been a star player for the past decade,there is a significant shift towards other noncarbon materials in recent years.Apart from the large family of transition metal dichalcogenides（TMDs）,mono-elemental materials,such as phosphorene,arsenene,antimonene.展开更多
基金supported by the Program for Equipment Pre-research Field Funds(No.6140414040116CB01012)the National Natural Science Foundation of China(Nos.61575051 and 11704086)the 111 project of the Harbin Engineering University(No.B13015)
文摘Ultrafast lasers play an important role in a variety of applications ranging from optical communications to medical diagnostics and industrial materials processing. Graphene and other two-dimensional（2D） noncarbon materials, including topological insulators（TIs）, transition metal dichalcogenides（TMDCs）, phosphorene, bismuthene, and antimonene, have witnessed a very fast development of both fundamental and practical aspects in ultrafast photonics since 2009. Their unique nonlinear optical properties enable them to be used as excellent saturable absorbers（SAs） that have fast responses and broadband operation, and can be easily integrated into lasers. Here, we catalog and review recent progress in the exploitation of these 2D noncarbon materials in this emerging field. The fabrication techniques, nonlinear optical properties, and device integration strategies of 2D noncarbon materials are first introduced with a comprehensive view. Then, various mode-locked/Q-switched lasers（e.g., fiber, solid-state, disk, and waveguide lasers） based on 2D noncarbon materials are reviewed. In addition, versatile soliton pulses generated from the mode-locked fiber lasers based on 2D noncarbon materials are also summarized. Finally, future challenges and perspectives of 2D materials-based lasers are addressed.
基金the Natural Science Foundation of China(Grant Nos.21606149,21832004,U1905215,and 51672046)Shanghai Rising-Star Program(18QB1404400)National Key Research and Development Program/Key Scientific Issues of Transformative Technology(2020YFA0710303).
文摘Electrochemical energy systems such as fuel cells and metal–air batteries can be used as clean power sources in the field of electric transportation and possess great potential in the reduction of various energy and environmental issues.In these systems,the oxygen reduction reaction(ORR)at the cathode is the rate-determining factor for overall system performance,and up to now,platinum group metals supported on carbon materials,especially Pt,remain the highest performing and the most practical ORR electrocatalysts.However,corresponding carbonaceous catalyst supports are extremely susceptible to corrosion under electrochemical operation,and therefore,the extensive exploration of alternative stable materials for ORR electrocatalysts with both high electrochemical stability and catalytic performance is essential.Here,noncarbon materials with high corrosion resistance have been explored to substitute traditional carbon supports or even act directly as low-cost non-noble metal electrocatalysts,and based on this,this review will present a comprehensive overview and deep analysis of the recent progress in noncarbon materials,including metals,oxides,nitrides,carbides,sulfides,and so on.Overall,general attributes associated with noncarbon materials include high corrosion resistance,strong metal–support interaction,and impressive porous structure retention.However,major drawbacks include low electrical conductivity,insufficient chemical stability in acidic or alkaline media,and poor electrochemical stability at ORR electrode potentials.To overcome these challenges,this review will also summarize efficient strategies such as combining with highly conductive materials,introducing dopants and forming vacancies to result in promising electrocatalytic ORR performances.Finally,this review will propose possible research directions to facilitate future research and development toward the practical application of noncarbon-based ORR electrocatalysts.
文摘Scientists are in the constant search of novel materials,or innovative applications of existing materials to solve problems we face in our everyday life.Although graphene,the two-dimensional（2D）form of carbon,has been a star player for the past decade,there is a significant shift towards other noncarbon materials in recent years.Apart from the large family of transition metal dichalcogenides（TMDs）,mono-elemental materials,such as phosphorene,arsenene,antimonene.
