The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spac...The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results.In this study,we compared two fluorinated salts:4-(trifluoromethyl)benzamidine hydrochloride(4TF-BA·HCl)and 4-fluorobenzamidine hydrochloride(4F-BA·HCl)to engineer the 3D/2D perovskite films.Surprisingly,4F-BA formed a high-performance 3D/2D heterojunction,while4TF-BA produced an amorphous layer on the perovskite films.Our findings indicate that the balanced intramolecular charge polarization,which leads to effective hydrogen bonding,is more favorable in 4F-BA than in 4TF-BA,promoting the formation of a crystalline 2D perovskite.Nevertheless,4TF-BA managed to improve efficiency to 24%,surpassing the control device,primarily due to the natural passivation capabilities of benzamidine.Interestingly,the devices based on 4F-BA demonstrated an efficiency exceeding 25%with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.展开更多
Photocatalytic hydrogen(H_(2))production via water splitting in the absence of sacrificial agents is a promising strategy for producing clean and sustainable hydrogen energy from solar energy.However,the realization o...Photocatalytic hydrogen(H_(2))production via water splitting in the absence of sacrificial agents is a promising strategy for producing clean and sustainable hydrogen energy from solar energy.However,the realization of a photocatalytic pure water splitting system with desirable efficiency is still a huge challenge.Herein,visible light photocatalytic H_(2) production from pure water splitting was successfully achieved using a g-C_(3)N_(4)/CoTiO_(3) S-scheme heterojunction photocatalyst in the absence of sacrificial agents.An optimum hydrogen evolution rate of 118μmol∙h^(−1)∙g^(−1) was reached with the addition of 1.5 wt%CoTiO_(3).The remarkably promoted hydrogen evolution rate was attributed to the intensified light absorption coupled with the synergistic effect of visible light responsive CoTiO_(3),the promoted efficiency in charge separation,and the reserved strong redox capacity induced by the S-scheme charge transfer mechanism.This work provides an alternative to visible light-responding oxidation photocatalysts for the construction of S-scheme heterojunctions and high-efficiency photocatalytic systems for pure water splitting.展开更多
With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an e...With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an energy density 10%–20%greater than that of LFP.Structural distortion caused by the Jahn–Teller effect decreases the capacity and voltage platform,thus restricting the commercialization of this material.Herein,ideas to overcome these challenges,including the crystal structure of LMFP and strategies to mitigate the Jahn–Teller distortion,are first explored.Then,the migration pathways of Li+during charging and discharging and the phase transition mechanisms that affect the material’s performance are discussed.Next,the optimal Mn:Fe ratio for achieving the desired performance is described.The influences of various synthesis and modification methods on the morphology and structure of LMFP are reviewed.Additionally,different modification techniques,such as doping and coating,to enhance the performance of LMFP are highlighted.Finally,an overview of the current state of research on the recycling and reuse of LMFP is provided.By addressing these key topics,this paper offers a theoretical foundation for the further development of LMFP,thus contributing to its eventual commercialization.展开更多
Sequential processing(SqP)of the active layer offers independent optimization of the donor and acceptor with more targeted solvent design,which is considered the most promising strategy for achieving efficient organic...Sequential processing(SqP)of the active layer offers independent optimization of the donor and acceptor with more targeted solvent design,which is considered the most promising strategy for achieving efficient organic solar cells(OSCs).In the SqP method,the favorable interpenetrating network seriously depends on the fine control of the bottom layer swelling.However,the choice of solvent(s)for both the donor and acceptor have been mostly based on a trial-and-error manner.A single solvent often cannot achieve sufficient yet not excessive swelling,which has long been a difficulty in the high efficient SqP OSCs.Herein,two new isomeric molecules are introduced to fine-tune the nucleation and crystallization dynamics that allows judicious control over the swelling of the bottom layer.The strong non-covalent interaction between the isomeric molecule and active materials provides an excellent driving force for optimize the swelling-process.Among them,the molecule with high dipole moment promotes earlier nucleation of the PM6 and provides extended time for crystallization during SqP,improving bulk morphology and vertical phase segregation.As a result,champion efficiencies of 17.38%and 20.00%(certified 19.70%)are achieved based on PM6/PYF-T-o(all-polymer)and PM6/BTP-eC9 devices casted by toluene solvent.展开更多
Photocatalytic CO_(2) conversion into valuable hydrocarbon fuels via solar light is a promising strategy to simul-taneously address energy shortage and environmental pollution.However,the photocatalytic CO_(2) reducti...Photocatalytic CO_(2) conversion into valuable hydrocarbon fuels via solar light is a promising strategy to simul-taneously address energy shortage and environmental pollution.However,the photocatalytic CO_(2) reduction performance is too poor to be practically utilized due to the rapid recombination of photogenerated charge carriers.Constructing step-scheme(S-scheme)heterojunction photocatalysts can facilitate the charge separation and maximize the redox ability,thus remarkably enhancing the photocatalytic CO_(2) reduction activity.This review summarizes the progress of S-scheme heterojunction photocatalysts applied in the photocatalytic CO_(2) reduction reactions.Firstly,we introduce the fundamental design principles and characterization methods.The direct and indirect techniques to confirm the S-scheme charge transfer mechanism are disclosed.Secondly,we divide S-scheme composite photocatalyst into the following categories depending on their compositions:g-C_(3)N_(4)-based,metal-chalcogenide-based,TiO_(2)-based,bismuth-based,other metal oxide-based and other semiconductor-based S-scheme photocatalysts.The synergistic effect of the S-scheme charge transfer pathway as well as the unique intrinsic properties of semiconductor materials on the photocatalytic CO_(2) reduction performance is discussed in detail.Finally,concluding perspectives on the challenges and opportunities for the further exploration of highly efficient S-scheme photocatalysts in photocatalytic CO_(2) conversion are presented.展开更多
基金supported by the National Key Research and Development Programs-Intergovernmental International Cooperation in Science and Technology Innovation Project(Grant No.2022YFE0118400)the Natural Science Foundation of Hunan Province(2023JJ50132)+1 种基金Shenzhen Science and Technology Innovation Committee(Grants Nos.JCYJ20220818100211025,and KCXST20221021111616039)Shenzhen Science and Technology Program(No.20231128110928003)。
文摘The introduction of two-dimensional(2D)perovskite layers on top of three-dimensional(3D)perovskite films enhances the performance and stability of perovskite solar cells(PSCs).However,the electronic effect of the spacer cation and the quality of the 2D capping layer are critical factors in achieving the required results.In this study,we compared two fluorinated salts:4-(trifluoromethyl)benzamidine hydrochloride(4TF-BA·HCl)and 4-fluorobenzamidine hydrochloride(4F-BA·HCl)to engineer the 3D/2D perovskite films.Surprisingly,4F-BA formed a high-performance 3D/2D heterojunction,while4TF-BA produced an amorphous layer on the perovskite films.Our findings indicate that the balanced intramolecular charge polarization,which leads to effective hydrogen bonding,is more favorable in 4F-BA than in 4TF-BA,promoting the formation of a crystalline 2D perovskite.Nevertheless,4TF-BA managed to improve efficiency to 24%,surpassing the control device,primarily due to the natural passivation capabilities of benzamidine.Interestingly,the devices based on 4F-BA demonstrated an efficiency exceeding 25%with greater longevity under various storage conditions compared to 4TF-BA-based and the control devices.
文摘Photocatalytic hydrogen(H_(2))production via water splitting in the absence of sacrificial agents is a promising strategy for producing clean and sustainable hydrogen energy from solar energy.However,the realization of a photocatalytic pure water splitting system with desirable efficiency is still a huge challenge.Herein,visible light photocatalytic H_(2) production from pure water splitting was successfully achieved using a g-C_(3)N_(4)/CoTiO_(3) S-scheme heterojunction photocatalyst in the absence of sacrificial agents.An optimum hydrogen evolution rate of 118μmol∙h^(−1)∙g^(−1) was reached with the addition of 1.5 wt%CoTiO_(3).The remarkably promoted hydrogen evolution rate was attributed to the intensified light absorption coupled with the synergistic effect of visible light responsive CoTiO_(3),the promoted efficiency in charge separation,and the reserved strong redox capacity induced by the S-scheme charge transfer mechanism.This work provides an alternative to visible light-responding oxidation photocatalysts for the construction of S-scheme heterojunctions and high-efficiency photocatalytic systems for pure water splitting.
基金supported by National Natural Science Foundation of China(Grant Nos.52302293 and 22272110)Innovation Project of Education Department of Guangdong Province(Grant No.2023KTSCX124)+2 种基金Shenzhen Science and Technology Program(Grant No.KJZD2023092311460401)Guangdong Higher Education Letter(Grant No.[2024]No.30)Shenzhen Key Laboratory of Applied Technologies of Super-Diamond and Functional Crystals(Grant No.ZDSYS20230626091303007).
文摘With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an energy density 10%–20%greater than that of LFP.Structural distortion caused by the Jahn–Teller effect decreases the capacity and voltage platform,thus restricting the commercialization of this material.Herein,ideas to overcome these challenges,including the crystal structure of LMFP and strategies to mitigate the Jahn–Teller distortion,are first explored.Then,the migration pathways of Li+during charging and discharging and the phase transition mechanisms that affect the material’s performance are discussed.Next,the optimal Mn:Fe ratio for achieving the desired performance is described.The influences of various synthesis and modification methods on the morphology and structure of LMFP are reviewed.Additionally,different modification techniques,such as doping and coating,to enhance the performance of LMFP are highlighted.Finally,an overview of the current state of research on the recycling and reuse of LMFP is provided.By addressing these key topics,this paper offers a theoretical foundation for the further development of LMFP,thus contributing to its eventual commercialization.
基金supported by the Guangdong Basic and Applied Basic Research Foundation (2022A1515010875)National Natural Science Foundation of China (12404480)+4 种基金Shenzhen Science and Technology Program (JCYJ20240813113238050, JCYJ20240813113306008)Education Department of Guangdong Province (2021KCXTD045)National Natural Science Foundation of China (12274303)the Shenzhen Key Laboratory of Applied Technologies of Super-Diamond and Functional Crystals (ZDSYS20230626091303007)Characteristic Innovation Foundation of Higher Education Institutions of Guangdong Province (2022KTSCX116)
文摘Sequential processing(SqP)of the active layer offers independent optimization of the donor and acceptor with more targeted solvent design,which is considered the most promising strategy for achieving efficient organic solar cells(OSCs).In the SqP method,the favorable interpenetrating network seriously depends on the fine control of the bottom layer swelling.However,the choice of solvent(s)for both the donor and acceptor have been mostly based on a trial-and-error manner.A single solvent often cannot achieve sufficient yet not excessive swelling,which has long been a difficulty in the high efficient SqP OSCs.Herein,two new isomeric molecules are introduced to fine-tune the nucleation and crystallization dynamics that allows judicious control over the swelling of the bottom layer.The strong non-covalent interaction between the isomeric molecule and active materials provides an excellent driving force for optimize the swelling-process.Among them,the molecule with high dipole moment promotes earlier nucleation of the PM6 and provides extended time for crystallization during SqP,improving bulk morphology and vertical phase segregation.As a result,champion efficiencies of 17.38%and 20.00%(certified 19.70%)are achieved based on PM6/PYF-T-o(all-polymer)and PM6/BTP-eC9 devices casted by toluene solvent.
基金This work was supported by the NSFC(22002091,22272110,22178224)the Fundamental Research Funds for Shenzhen Technology University(20211063010047)+5 种基金Guangdong Basic and Applied Basic Research Foundation(2020A1515110873)the University Engineering Research Center of Crystal Growth and Applications of Guangdong Province(2020GCZX005)Shenzhen Fundamental Research Program(JCYJ20190813113408912)Natural Science Foundation of Top Talent of SZTU(2019211)Shenzhen Stable Supporting Program(SZWD2021015,20220716001753001)Science and Technology Project from Guangdong Department of Education(2021ZDJS110).
文摘Photocatalytic CO_(2) conversion into valuable hydrocarbon fuels via solar light is a promising strategy to simul-taneously address energy shortage and environmental pollution.However,the photocatalytic CO_(2) reduction performance is too poor to be practically utilized due to the rapid recombination of photogenerated charge carriers.Constructing step-scheme(S-scheme)heterojunction photocatalysts can facilitate the charge separation and maximize the redox ability,thus remarkably enhancing the photocatalytic CO_(2) reduction activity.This review summarizes the progress of S-scheme heterojunction photocatalysts applied in the photocatalytic CO_(2) reduction reactions.Firstly,we introduce the fundamental design principles and characterization methods.The direct and indirect techniques to confirm the S-scheme charge transfer mechanism are disclosed.Secondly,we divide S-scheme composite photocatalyst into the following categories depending on their compositions:g-C_(3)N_(4)-based,metal-chalcogenide-based,TiO_(2)-based,bismuth-based,other metal oxide-based and other semiconductor-based S-scheme photocatalysts.The synergistic effect of the S-scheme charge transfer pathway as well as the unique intrinsic properties of semiconductor materials on the photocatalytic CO_(2) reduction performance is discussed in detail.Finally,concluding perspectives on the challenges and opportunities for the further exploration of highly efficient S-scheme photocatalysts in photocatalytic CO_(2) conversion are presented.
