Flowing water can be used as an energy source for generators,providing a major part of the energy for daily life.However,water is rarely used for information or electronic devices.Herein,we present the feasibility of ...Flowing water can be used as an energy source for generators,providing a major part of the energy for daily life.However,water is rarely used for information or electronic devices.Herein,we present the feasibility of a polarized liquid-triggered photodetector in which polarized water is sandwiched between graphene and a semiconductor.Due to the polarization and depolarization processes of water molecules driven by photogenerated carriers,a photo-sensitive current can be repeatedly produced,resulting in a high-performance photodetector.The response wavelength of the photodetector can be fine-tuned as a result of the free choice of semiconductors as there is no requirement of lattice match between graphene and the semiconductors.Under zero voltage bias,the responsivity and specific detectivity of Gr/NaCl(0.5 M)W/N-GaN reach values of 130.7 mA/W and 2.3×10^(9)Jones under 350 nm illumination,respectively.Meanwhile,using a polar liquid photodetector can successfully read the photoplethysmography signals to produce accurate oxygen blood saturation and heart rate.Compared with the commercial pulse oximetry sensor,the average errors of oxygen saturation and heart rate in the designed photoplethysmography sensor are~1.9%and~2.1%,respectively.This study reveals that water can be used as a high-performance photodetector in informative industries.展开更多
The excitation,rebound,and transport process of hot carriers(HCs)inside dynamic diode(DD)based on insulators has been rarely explored due to the original stereotyped in which it was thought that the insulators are non...The excitation,rebound,and transport process of hot carriers(HCs)inside dynamic diode(DD)based on insulators has been rarely explored due to the original stereotyped in which it was thought that the insulators are nonconductive.However,the carrier dynamics of DD is totally different from the static diode,which may bring a subverting insight of insulators.展开更多
Thermoresponsive hydrogels have been designed for smart windows to dynamically modulate solar radiation,but their inherent drawbacks of long response time and imperfectly matched phase transition temperature have limi...Thermoresponsive hydrogels have been designed for smart windows to dynamically modulate solar radiation,but their inherent drawbacks of long response time and imperfectly matched phase transition temperature have limited their wide applications.This work reports a novel composite hydrogel consisting of hydroxypropyl cellulose,polyacrylic acid,and carbon quantum dots with intriguing features of tunable transition temperature and enhanced switching speed.The composite hydrogel demonstrated flexible tunability in transition temperature by controlling the hydrogen ion concentration and a fast response speed by dopping with carbon dots for efficient photothermal conversion.The building energy simulation was carried out to investigate the impacts of transition temperature variations and solar regulations on the space cooling/heating loads under different climate conditions,revealing the necessity of tunability of both transition temperature and solar transmittance in thermochromic smart windows.This novel design of thermochromic composite hydrogel provides insight into theoretical and experimental support for future adaptive building envelopes.展开更多
There is a rising prospective in harvesting energy from the environment,as in situ energy is required for the distributed sensors in the interconnected information society,among which the water flow energy is the most...There is a rising prospective in harvesting energy from the environment,as in situ energy is required for the distributed sensors in the interconnected information society,among which the water flow energy is the most potential candidate as a clean and abundant mechanical source.However,for microscale and unordered movement of water,achieving a sustainable direct-current generating device with high output to drive the load element is still challenging,which requires for further exploration.Herein,we propose a dynamic PN water junction generator with moving water sandwiched between two semiconductors,which outputs a sustainable direct-current voltage of 0.3 V and a current of 0.64μA.The mechanism can be attributed to the dynamic polarization process of water as moving dielectric medium in the dynamic PN water junction,under the Fermi level difference of two semiconductors.We further demonstrate an encapsulated portable power-generating device with simple structure and continuous direct-current voltage output of 0.11 V,which exhibits its promising potential application in the field of wearable devices and the IoTs.展开更多
Searching for light and miniaturized functional device structures for sustainable energy gathering from the environment is the focus of energy society with the development of the internet of things.The proposal of a d...Searching for light and miniaturized functional device structures for sustainable energy gathering from the environment is the focus of energy society with the development of the internet of things.The proposal of a dynamic heterojunction-based direct current generator builds up new platforms for developing in situ energy.However,the requirement of different semiconductors in dynamic heterojunction is too complex to wide applications,generating energy loss for crystal structure mismatch.Herein,dynamic homojunction generators are explored,with the same semiconductor and majority carrier type.Systematic experiments reveal that the majority of carrier directional separation originates from the breaking symmetry between carrier distribution,leading to the rebounding effect of carriers by the interfacial electric field.Strikingly,NN Si homojunction with different Fermi levels can also output the electricity with higher current density than PP/PN homojunction,attributing to higher carrier mobility.The current density is as high as 214.0 A/m^(2),and internal impedance is as low as 3.6 kΩ,matching well with the impedance of electron components.Furthermore,the N-i-N structure is explored,whose output voltage can be further improved to 1.3V in the case of the N-Si/Al2O3/N-Si structure,attributing to the enhanced interfacial barrier.This approach provides a simple and feasible way of converting low-frequency disordered mechanical motion into electricity.展开更多
Recharging the batteries by wireless energy facilitates the long-term running of the batteries,which will save numerous works of battery maintenance and replacement.Thus,harvesting energy form radio frequency(RF)waves...Recharging the batteries by wireless energy facilitates the long-term running of the batteries,which will save numerous works of battery maintenance and replacement.Thus,harvesting energy form radio frequency(RF)waves has become the most promising solution for providing the micropower needed for wireless sensor applications,especially in a widely distributed 4G/5G wireless network.However,the current research on rectenna is mainly focused on the integrated antenna coupled with metal-insulator-metal tunneling diodes.Herein,by adopting the plasmon excitation of graphene and quantum tunneling process between graphene and GaAs or GaN,we demonstrated the feasibility of harvesting energy from the 915MHz wireless source belonging to 5G in the FR1 range(450MHz-6 GHz)which is also known as sub-6G.The generated current and voltage can be observed continuously,with the direction defined by the built-in field between graphene and GaAs and the incident electromagnetic waves treated as the quantum energy source.Under the RF illumination,the generated current increases rapidly and the value can reach in the order of 10^(-8)-10^(-7)A.The harvester can work under the multiple channel mode,harvesting energy simultaneously from different flows of wireless energy in the air.This research will open a new avenue for wireless harvesting by using the ultrafast process of quantum tunneling and unique physical properties of graphene.展开更多
Static heterojunction-based electronic devices have been widely applied because carrier dynamic processes between semiconductors can be designed through band gap engineering.Herein,we demonstrate a tunable direct-curr...Static heterojunction-based electronic devices have been widely applied because carrier dynamic processes between semiconductors can be designed through band gap engineering.Herein,we demonstrate a tunable direct-current generator based on the dynamic heterojunction,whose mechanism is based on breaking the symmetry of drift and diffusion currents and rebounding hot carrier transport in dynamic heterojunctions.Furthermore,the output voltage can be delicately adjusted and enhanced with the interface energy level engineering of inserting dielectric layers.Under the ultrahigh interface electric field,hot electrons will still transfer across the interface through the tunneling and hopping effect.In particular,the intrinsic anisotropy of black phosphorus arising from the lattice structure produces extraordinary electronic,transport,and mechanical properties exploited in our dynamic heterojunction generator.Herein,the voltage of 6.1 V,current density of 124.0 A/m^(2),power density of 201.0 W/m^(2),and energy-conversion efficiency of 31.4%have been achieved based on the dynamic black phosphorus/AlN/Si heterojunction,which can be used to directly and synchronously light up light-emitting diodes.This direct-current generator has the potential to convert ubiquitous mechanical energy into electric energy and is a promising candidate for novel portable and miniaturized power sources in the in situ energy acquisition field.展开更多
基金support from the National Natural Science Foundation of China(Nos.51202216,51551203,and 61774135)the Distinguished Youth Fund of Zhejiang Natural Science Foundation of China(LR21F040001)+1 种基金the Special Foundation of Young Professor of Zhejiang University(2013QNA5007)support from the China Postdoctoral Science Foundation(2021M692767).
文摘Flowing water can be used as an energy source for generators,providing a major part of the energy for daily life.However,water is rarely used for information or electronic devices.Herein,we present the feasibility of a polarized liquid-triggered photodetector in which polarized water is sandwiched between graphene and a semiconductor.Due to the polarization and depolarization processes of water molecules driven by photogenerated carriers,a photo-sensitive current can be repeatedly produced,resulting in a high-performance photodetector.The response wavelength of the photodetector can be fine-tuned as a result of the free choice of semiconductors as there is no requirement of lattice match between graphene and the semiconductors.Under zero voltage bias,the responsivity and specific detectivity of Gr/NaCl(0.5 M)W/N-GaN reach values of 130.7 mA/W and 2.3×10^(9)Jones under 350 nm illumination,respectively.Meanwhile,using a polar liquid photodetector can successfully read the photoplethysmography signals to produce accurate oxygen blood saturation and heart rate.Compared with the commercial pulse oximetry sensor,the average errors of oxygen saturation and heart rate in the designed photoplethysmography sensor are~1.9%and~2.1%,respectively.This study reveals that water can be used as a high-performance photodetector in informative industries.
基金S Lin thanks the support from the National Natural Science Foundation of China(Nos.51202216,51551203,and 61774135)the Special Foundation of Young Professor of Zhejiang University(Grant No.2013QNA5007)+1 种基金the Outstanding Youth Fund of Zhejiang Natural Science Foundation of China(Grant LR21F040001)Y Lu thanks the support from the China Postdoctoral Science Foundation(2021M692767).
文摘The excitation,rebound,and transport process of hot carriers(HCs)inside dynamic diode(DD)based on insulators has been rarely explored due to the original stereotyped in which it was thought that the insulators are nonconductive.However,the carrier dynamics of DD is totally different from the static diode,which may bring a subverting insight of insulators.
基金supported by the National Key Research and Development Program of China(2023YFC3806300)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_1485)
文摘Thermoresponsive hydrogels have been designed for smart windows to dynamically modulate solar radiation,but their inherent drawbacks of long response time and imperfectly matched phase transition temperature have limited their wide applications.This work reports a novel composite hydrogel consisting of hydroxypropyl cellulose,polyacrylic acid,and carbon quantum dots with intriguing features of tunable transition temperature and enhanced switching speed.The composite hydrogel demonstrated flexible tunability in transition temperature by controlling the hydrogen ion concentration and a fast response speed by dopping with carbon dots for efficient photothermal conversion.The building energy simulation was carried out to investigate the impacts of transition temperature variations and solar regulations on the space cooling/heating loads under different climate conditions,revealing the necessity of tunability of both transition temperature and solar transmittance in thermochromic smart windows.This novel design of thermochromic composite hydrogel provides insight into theoretical and experimental support for future adaptive building envelopes.
基金S.S.Lin thanks the support from the National Natural Science Foundation of China(No.51202216,51502264,61774135)K.H.Liu thanks the support from the Beijing Natural Science Foundation(JQ19004)+4 种基金Beijing Excellent Talents Training Support(2017000026833ZK11)Bureau of Industry and Information Technology of Shenzhen(No.201901161512)Key-Area Research and Development Program of Guangdong Province(Grant Nos.2019B010931001,2020B010189001)Project funded by the China Postdoctoral Science Foundation(2019M660001)Postdoctoral Innovative Personnel Support Program(BX20180013).
文摘There is a rising prospective in harvesting energy from the environment,as in situ energy is required for the distributed sensors in the interconnected information society,among which the water flow energy is the most potential candidate as a clean and abundant mechanical source.However,for microscale and unordered movement of water,achieving a sustainable direct-current generating device with high output to drive the load element is still challenging,which requires for further exploration.Herein,we propose a dynamic PN water junction generator with moving water sandwiched between two semiconductors,which outputs a sustainable direct-current voltage of 0.3 V and a current of 0.64μA.The mechanism can be attributed to the dynamic polarization process of water as moving dielectric medium in the dynamic PN water junction,under the Fermi level difference of two semiconductors.We further demonstrate an encapsulated portable power-generating device with simple structure and continuous direct-current voltage output of 0.11 V,which exhibits its promising potential application in the field of wearable devices and the IoTs.
基金This work was funded by the National Natural Science Foundation of China(Nos.51202216,51502264,and 61774135)Special Foundation of Young Professor of Zhejiang University(No.2013QNA5007)Y.Wen thanks the support from the Science and Technology Project of Jiangsu Province Special Equipment Safety Supervision and Inspection Institute(KJY2017016).
文摘Searching for light and miniaturized functional device structures for sustainable energy gathering from the environment is the focus of energy society with the development of the internet of things.The proposal of a dynamic heterojunction-based direct current generator builds up new platforms for developing in situ energy.However,the requirement of different semiconductors in dynamic heterojunction is too complex to wide applications,generating energy loss for crystal structure mismatch.Herein,dynamic homojunction generators are explored,with the same semiconductor and majority carrier type.Systematic experiments reveal that the majority of carrier directional separation originates from the breaking symmetry between carrier distribution,leading to the rebounding effect of carriers by the interfacial electric field.Strikingly,NN Si homojunction with different Fermi levels can also output the electricity with higher current density than PP/PN homojunction,attributing to higher carrier mobility.The current density is as high as 214.0 A/m^(2),and internal impedance is as low as 3.6 kΩ,matching well with the impedance of electron components.Furthermore,the N-i-N structure is explored,whose output voltage can be further improved to 1.3V in the case of the N-Si/Al2O3/N-Si structure,attributing to the enhanced interfacial barrier.This approach provides a simple and feasible way of converting low-frequency disordered mechanical motion into electricity.
基金The authors thank the support from the National Natural Science Foundation of China(Nos.51202216,51502264,and 61774135)the Special Foundation of Young Professor of Zhejiang University(Grant No.2013QNA5007).
文摘Recharging the batteries by wireless energy facilitates the long-term running of the batteries,which will save numerous works of battery maintenance and replacement.Thus,harvesting energy form radio frequency(RF)waves has become the most promising solution for providing the micropower needed for wireless sensor applications,especially in a widely distributed 4G/5G wireless network.However,the current research on rectenna is mainly focused on the integrated antenna coupled with metal-insulator-metal tunneling diodes.Herein,by adopting the plasmon excitation of graphene and quantum tunneling process between graphene and GaAs or GaN,we demonstrated the feasibility of harvesting energy from the 915MHz wireless source belonging to 5G in the FR1 range(450MHz-6 GHz)which is also known as sub-6G.The generated current and voltage can be observed continuously,with the direction defined by the built-in field between graphene and GaAs and the incident electromagnetic waves treated as the quantum energy source.Under the RF illumination,the generated current increases rapidly and the value can reach in the order of 10^(-8)-10^(-7)A.The harvester can work under the multiple channel mode,harvesting energy simultaneously from different flows of wireless energy in the air.This research will open a new avenue for wireless harvesting by using the ultrafast process of quantum tunneling and unique physical properties of graphene.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51202216,51502264,and 61774135)the Special Foundation of Young Professor of Zhejiang University(Grant No.2013QNA5007).
文摘Static heterojunction-based electronic devices have been widely applied because carrier dynamic processes between semiconductors can be designed through band gap engineering.Herein,we demonstrate a tunable direct-current generator based on the dynamic heterojunction,whose mechanism is based on breaking the symmetry of drift and diffusion currents and rebounding hot carrier transport in dynamic heterojunctions.Furthermore,the output voltage can be delicately adjusted and enhanced with the interface energy level engineering of inserting dielectric layers.Under the ultrahigh interface electric field,hot electrons will still transfer across the interface through the tunneling and hopping effect.In particular,the intrinsic anisotropy of black phosphorus arising from the lattice structure produces extraordinary electronic,transport,and mechanical properties exploited in our dynamic heterojunction generator.Herein,the voltage of 6.1 V,current density of 124.0 A/m^(2),power density of 201.0 W/m^(2),and energy-conversion efficiency of 31.4%have been achieved based on the dynamic black phosphorus/AlN/Si heterojunction,which can be used to directly and synchronously light up light-emitting diodes.This direct-current generator has the potential to convert ubiquitous mechanical energy into electric energy and is a promising candidate for novel portable and miniaturized power sources in the in situ energy acquisition field.
