Mechanistic studies promote scientific development from phenomena to theories.Aggregation-induced emission(AIE),as an unusual photophysical phenomenon,builds the bridge between molecular science and aggregate mesoscie...Mechanistic studies promote scientific development from phenomena to theories.Aggregation-induced emission(AIE),as an unusual photophysical phenomenon,builds the bridge between molecular science and aggregate mesoscience.With the twenty-year development of AIE,restriction of intramolecular motion(RIM)has been verified as the working mechanism of AIE effect.In this review,these mechanistic works about RIM are summarized from experimental and theoretical perspectives.Thereinto,the experimental studies are introduced from three parts:external rigidification,structural modification and structural characterization.In the theoretical part,calculations on the low-frequency motion of AIEgens have been performed to prove the RIM mechanism.By virtue of the theoretical calculations,some new mechanisms are proposed to supplement the RIM,such as restriction of access to conical intersection,suppression of Kasha transition,restriction of access to dark state,etc.It is foreseeable that the RIM mechanism will unify the photophysical theories for both molecules and aggregates,and inspire more progress in aggregate science.展开更多
Recent years have seen a rapid development of lead halide perovskite(LHP)nanocrystals(NCs)as new and promising functional nanomaterials,which exhibit strong potential in a wide range of optoelectronic applications due...Recent years have seen a rapid development of lead halide perovskite(LHP)nanocrystals(NCs)as new and promising functional nanomaterials,which exhibit strong potential in a wide range of optoelectronic applications due to their superior properties and solution-processable advantages.However,to promote their progress in commercialization,overcoming the drawbacks of intrinsic lead toxicity and optimizing material performance are important and must be solved using alternative metal ions to replace Pb ions.In this review,we primarily summarize the recent development of lead-substitution strategies,which focus on the commonalities and differences of their functionalities that are induced by various doped ions.After a brief introduction to the synthesis,nucleation and growth of all-inorganic LHP NCs,a deep discussion of the crystalline structure,electronic band structure,defect states,exciton binding energy,exciton photodynamic process and stability is followed.Specifically,we highlight the importance of both theoretical calculations and experimental characterizations to establish indicative guidelines for high-performance semiconductor nanomaterials.Finally,the light emission applications are discussed,and several issues concerning future research on the controllable synthesis of halide perovskite NCs with low toxicity,superior reproducibility and properties are outlined.展开更多
基金This work is supported by the National Natural Science Foundation of China(No.21788102)the Research Grants of Council of Hong Kong,China(Nos.16304819,16305618,N_HKUST609/19,C6009-17G)the Innovation of Technology Commission of Hong Kong,China(No.ITC-CNERC14SC01).
文摘Mechanistic studies promote scientific development from phenomena to theories.Aggregation-induced emission(AIE),as an unusual photophysical phenomenon,builds the bridge between molecular science and aggregate mesoscience.With the twenty-year development of AIE,restriction of intramolecular motion(RIM)has been verified as the working mechanism of AIE effect.In this review,these mechanistic works about RIM are summarized from experimental and theoretical perspectives.Thereinto,the experimental studies are introduced from three parts:external rigidification,structural modification and structural characterization.In the theoretical part,calculations on the low-frequency motion of AIEgens have been performed to prove the RIM mechanism.By virtue of the theoretical calculations,some new mechanisms are proposed to supplement the RIM,such as restriction of access to conical intersection,suppression of Kasha transition,restriction of access to dark state,etc.It is foreseeable that the RIM mechanism will unify the photophysical theories for both molecules and aggregates,and inspire more progress in aggregate science.
基金supported by Shanghai Science and Technology Committee(No.21ZR1408800)the National Natural Science Foundation of China(No.11975081).
文摘Recent years have seen a rapid development of lead halide perovskite(LHP)nanocrystals(NCs)as new and promising functional nanomaterials,which exhibit strong potential in a wide range of optoelectronic applications due to their superior properties and solution-processable advantages.However,to promote their progress in commercialization,overcoming the drawbacks of intrinsic lead toxicity and optimizing material performance are important and must be solved using alternative metal ions to replace Pb ions.In this review,we primarily summarize the recent development of lead-substitution strategies,which focus on the commonalities and differences of their functionalities that are induced by various doped ions.After a brief introduction to the synthesis,nucleation and growth of all-inorganic LHP NCs,a deep discussion of the crystalline structure,electronic band structure,defect states,exciton binding energy,exciton photodynamic process and stability is followed.Specifically,we highlight the importance of both theoretical calculations and experimental characterizations to establish indicative guidelines for high-performance semiconductor nanomaterials.Finally,the light emission applications are discussed,and several issues concerning future research on the controllable synthesis of halide perovskite NCs with low toxicity,superior reproducibility and properties are outlined.
