Molecular ferroelastics with the natural features of mechanical flexibility and switchable spontaneous strain have attracted widespread attention in the scientific community due to their potential applications in tuna...Molecular ferroelastics with the natural features of mechanical flexibility and switchable spontaneous strain have attracted widespread attention in the scientific community due to their potential applications in tunable gratings,flexible memorizers,strain sensors,and intelligent actuators.However,most designs of molecular ferroelastics remain in the stage of blind exploration,posing a challenge to achieve a functional ferroelastic more effectively.Herein,we have successfully obtained a molecular ferroelastic,[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2)(Me_(2)NH(CH_(2))_(2)NH_(3)=N,N-dimethylethylenediammonium),under the guidance of the mono-/double-protonation strategy.The_double-protonated[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2) undergoes a paraelastic-ferroelastic phase transition with the Aizu notation of 2/mFi at 322 K.Meanwhile,the theoretical calculation and experimental measurement simultaneously show that[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2) possesses good mechanical flexibility,because its elastic modulus(E)of 8.26 GPa and hardness(H)of 0.45 GPa are smaller than the average values of organic crystals(E of 12.05 GPa and H of 0.5 GPa),which makes it promising to apply in wearable pressure sensors,implantable medical sensors,high-precision tuners,etc.This work further enriches the molecular ferroelastic family and demonstrates that mono-/double-protonation is one of the effective molecular modification strategies for designing ferroelastics.展开更多
Lead-based organic-inorganic hybrids occupy a niche in the field of optoelectronics due to exceptional semiconducting properties and potential ferroelasticity.Nevertheless,the possible toxicity of lead restricts their...Lead-based organic-inorganic hybrids occupy a niche in the field of optoelectronics due to exceptional semiconducting properties and potential ferroelasticity.Nevertheless,the possible toxicity of lead restricts their widespread application to a certain extent.Herein,two new lead-free ferroelastic semiconductors are reported:[DMMClEA]_(3)Bi_(2)Br_(9)(compound 1)and[DMMClEA]_(3)Sb_(2)Br_(9)(compound 2)(DMMClEA=N-(chloromethyl)-N,N-dimethylethylammonium),in which the inorganic framework neatly arranges with[Bi_(2)Br_(9)]^(3−)/[Sb_(2)Br_(9)]^(3−)polyhedrons shared by face,forming an A_(3)B_(2)X_(9)-type structure.Both compounds 1 and 2 possess two-step phase transitions,including a3mF2/m-type ferroelastic phase transition,based on the Aizu rule.In addition,dual dielectric switches endow the application toward sensor devices.This finding enriches A_(3)B_(2)X_(9)-type zero-dimensional hybrid ferroelastics and provides an approach to designing high-performance,lead-free perovskite semiconductors with dielectric functionality.展开更多
基金financially supported by Southeast University and the National Natural Science Foundation of China(Grant Nos.21991141 and 22371258).
文摘Molecular ferroelastics with the natural features of mechanical flexibility and switchable spontaneous strain have attracted widespread attention in the scientific community due to their potential applications in tunable gratings,flexible memorizers,strain sensors,and intelligent actuators.However,most designs of molecular ferroelastics remain in the stage of blind exploration,posing a challenge to achieve a functional ferroelastic more effectively.Herein,we have successfully obtained a molecular ferroelastic,[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2)(Me_(2)NH(CH_(2))_(2)NH_(3)=N,N-dimethylethylenediammonium),under the guidance of the mono-/double-protonation strategy.The_double-protonated[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2) undergoes a paraelastic-ferroelastic phase transition with the Aizu notation of 2/mFi at 322 K.Meanwhile,the theoretical calculation and experimental measurement simultaneously show that[Me_(2)NH(CH_(2))_(2)NH_(3)](ReO_(4))_(2) possesses good mechanical flexibility,because its elastic modulus(E)of 8.26 GPa and hardness(H)of 0.45 GPa are smaller than the average values of organic crystals(E of 12.05 GPa and H of 0.5 GPa),which makes it promising to apply in wearable pressure sensors,implantable medical sensors,high-precision tuners,etc.This work further enriches the molecular ferroelastic family and demonstrates that mono-/double-protonation is one of the effective molecular modification strategies for designing ferroelastics.
基金financially supported by the National Natural Science Foundation of China(grant no.21991141).
文摘Lead-based organic-inorganic hybrids occupy a niche in the field of optoelectronics due to exceptional semiconducting properties and potential ferroelasticity.Nevertheless,the possible toxicity of lead restricts their widespread application to a certain extent.Herein,two new lead-free ferroelastic semiconductors are reported:[DMMClEA]_(3)Bi_(2)Br_(9)(compound 1)and[DMMClEA]_(3)Sb_(2)Br_(9)(compound 2)(DMMClEA=N-(chloromethyl)-N,N-dimethylethylammonium),in which the inorganic framework neatly arranges with[Bi_(2)Br_(9)]^(3−)/[Sb_(2)Br_(9)]^(3−)polyhedrons shared by face,forming an A_(3)B_(2)X_(9)-type structure.Both compounds 1 and 2 possess two-step phase transitions,including a3mF2/m-type ferroelastic phase transition,based on the Aizu rule.In addition,dual dielectric switches endow the application toward sensor devices.This finding enriches A_(3)B_(2)X_(9)-type zero-dimensional hybrid ferroelastics and provides an approach to designing high-performance,lead-free perovskite semiconductors with dielectric functionality.
