4D printing has attracted great interest since the concept was introduced in 2012. The past 5 years have witnessed rapid advances in both 4D printing processes and materials. Unlike 3D printing, 4D printing allows the...4D printing has attracted great interest since the concept was introduced in 2012. The past 5 years have witnessed rapid advances in both 4D printing processes and materials. Unlike 3D printing, 4D printing allows the printed part to change its shape and function with time in response to change in external conditions such as temperature, light, electricity, and water. In this review, we first overview the history of 4D printing and discuss its definition. We then summarize recent technological advances in 4D printing with focuses on methods, materials, and their intrinsic links. Finally, we discuss potential applications and offer perspectives for this exciting new field.展开更多
A novel solvent-sensitive fluorescent actuator with reversibility has been obtained from carbon dots （CDs） inverse opals, which is prepared via infiltrating CDs solution into the interstice of colloidal crystal temp...A novel solvent-sensitive fluorescent actuator with reversibility has been obtained from carbon dots （CDs） inverse opals, which is prepared via infiltrating CDs solution into the interstice of colloidal crystal template, thermal polymerization of CDs materials and removing the colloidal template. The as-prepared CDs inverse opal actuator shows a bending angle of 75° in 10.2 s, bending rate of 7.35 （°）.s-1. In particular, the fluorescence intensity of the films varies during the actuating process. The actuating behavior is attributed to the inhomogeneous swelling/shrinking of the film, which originates from the gradient dewetting by solvent evaporation and hydrogen-bonding interaction between the solvent molecules and oxygen/hydrogen ions of CDs side chain. The CDs inverse opal actuator has the advantages of quick response, good repeatability and strong fluorescence, which gives an important insight into the design and manufacture of novel and advanced solvent-actuators.展开更多
The performance of organic solar cells(OSCs)is mainly related to the bulk heterojunction(BHJ)microstructure of specific active layer systems,which is often in a metastable state.A promising strategy to address the abo...The performance of organic solar cells(OSCs)is mainly related to the bulk heterojunction(BHJ)microstructure of specific active layer systems,which is often in a metastable state.A promising strategy to address the abovementioned shortcomings of BHJs is to develop single-component active layer materials.Owing to the single-component small molecule materials with defined chemical structures generally exhibit poor absorption spectra,herein we first introduced narrow bandgap Y-series acceptors into the molecular skeleton of single-component materials,and designed two molecular dyads,SM-Et-1Y and SM-Et-2Y.The optical bandgaps(E_g~(opt)s)of the two dyads are 1.364 and 1.361 eV,respectively,which are much smaller than those of previously reported single-component molecules.Consequently,the SM-Et-2Y-based single-component OSCs(SCOSCs)showed a power conversion efficiency(PCE)of 5.07%,superior to SM-Et-1Y(2.53%),which is one of the highest PCEs reported for SCOSCs to date.Moreover,both SM-Et-1Y-and SM-Et-2Y-based devices exhibited excellent photo-stability,retaining over 90%of their initial performance after 250 h of continuous illumination.Our results provide a deeper understanding of the molecular backbone and a guiding principle for the rational design or selection of non-fullerene single-component materials with suitable donor/acceptor ratios.展开更多
Organic photovoltaics (OPV) can potentially combine low cost, lightness, flexibility and low environmental impact. In less than two decades, the power conversion efficiency(PCE) of OPV cells has increased from 1 to mo...Organic photovoltaics (OPV) can potentially combine low cost, lightness, flexibility and low environmental impact. In less than two decades, the power conversion efficiency(PCE) of OPV cells has increased from 1 to more than 15%thanks to parallel efforts in material design and device technology.展开更多
The environmental micro-energy harvested by the triboelectric–electromagnetic hybrid generator(TEHG)can power sensors and Internet of Things(IoT)nodes in smart agriculture.However,the separation structure of traditio...The environmental micro-energy harvested by the triboelectric–electromagnetic hybrid generator(TEHG)can power sensors and Internet of Things(IoT)nodes in smart agriculture.However,the separation structure of traditional TEHG raises the complexity of form and material,which is harmful to the miniaturization of the device.Herein,a single-material-substrated triboelectric–electromagnetic hybrid generator(SMS-TEHG)based on the flexible magnets is designed to achieve the structural integration of triboelectric nanogenerator(TENG)and electromagnetic generator(EMG).The flexible magnets serve as the electropositive triboelectric materials for TENG and the magnetic materials for EMG,simplifying the structural complexity of TEHG.The open-circuit voltage(VOC)of the TENG and EMG are 187.2 and 9.0 V at 300 rpm,respectively.After 30,000 cycles of stability testing,the VOC of the TENG and EMG retain about 95.6%and 99.3%,respectively.Additionally,the self-powered applications driven by SMS-TEHG in intelligent greenhouse have been successfully demonstrated,such as crop light supplementation,rain monitoring,and wireless temperature and humidity sensing.This work provides a new design for TEHG and possibilities for applying TEHG and IoT in smart agriculture.展开更多
基金financially supported by the National Natural Science Funds for Distinguished Young Scholar (No.21625402)the National Natural Science Funds for Youths (No.21604070)
文摘4D printing has attracted great interest since the concept was introduced in 2012. The past 5 years have witnessed rapid advances in both 4D printing processes and materials. Unlike 3D printing, 4D printing allows the printed part to change its shape and function with time in response to change in external conditions such as temperature, light, electricity, and water. In this review, we first overview the history of 4D printing and discuss its definition. We then summarize recent technological advances in 4D printing with focuses on methods, materials, and their intrinsic links. Finally, we discuss potential applications and offer perspectives for this exciting new field.
基金the Ministry of Science and Technology of China(Nos.2016YFA0200803 and2016YFB0402004)the National Natural Science Foundation of China(Nos.51673207 and 51373183)Scientific Research Fund of Hunan Provincial Science and Technology Department(No.09236)
文摘A novel solvent-sensitive fluorescent actuator with reversibility has been obtained from carbon dots （CDs） inverse opals, which is prepared via infiltrating CDs solution into the interstice of colloidal crystal template, thermal polymerization of CDs materials and removing the colloidal template. The as-prepared CDs inverse opal actuator shows a bending angle of 75° in 10.2 s, bending rate of 7.35 （°）.s-1. In particular, the fluorescence intensity of the films varies during the actuating process. The actuating behavior is attributed to the inhomogeneous swelling/shrinking of the film, which originates from the gradient dewetting by solvent evaporation and hydrogen-bonding interaction between the solvent molecules and oxygen/hydrogen ions of CDs side chain. The CDs inverse opal actuator has the advantages of quick response, good repeatability and strong fluorescence, which gives an important insight into the design and manufacture of novel and advanced solvent-actuators.
基金supported by the National Natural Science Foundation of China(52061135206,22279094)the Fundamental Research Funds for the Central Universities。
文摘The performance of organic solar cells(OSCs)is mainly related to the bulk heterojunction(BHJ)microstructure of specific active layer systems,which is often in a metastable state.A promising strategy to address the abovementioned shortcomings of BHJs is to develop single-component active layer materials.Owing to the single-component small molecule materials with defined chemical structures generally exhibit poor absorption spectra,herein we first introduced narrow bandgap Y-series acceptors into the molecular skeleton of single-component materials,and designed two molecular dyads,SM-Et-1Y and SM-Et-2Y.The optical bandgaps(E_g~(opt)s)of the two dyads are 1.364 and 1.361 eV,respectively,which are much smaller than those of previously reported single-component molecules.Consequently,the SM-Et-2Y-based single-component OSCs(SCOSCs)showed a power conversion efficiency(PCE)of 5.07%,superior to SM-Et-1Y(2.53%),which is one of the highest PCEs reported for SCOSCs to date.Moreover,both SM-Et-1Y-and SM-Et-2Y-based devices exhibited excellent photo-stability,retaining over 90%of their initial performance after 250 h of continuous illumination.Our results provide a deeper understanding of the molecular backbone and a guiding principle for the rational design or selection of non-fullerene single-component materials with suitable donor/acceptor ratios.
文摘Organic photovoltaics (OPV) can potentially combine low cost, lightness, flexibility and low environmental impact. In less than two decades, the power conversion efficiency(PCE) of OPV cells has increased from 1 to more than 15%thanks to parallel efforts in material design and device technology.
基金the National Key Research&Development Project from the Minister of Science and Technology(Nos.2021YFA1201601 and 2021YFA1201604)the Beijing Natural Science Foundation(No.3222023).
文摘The environmental micro-energy harvested by the triboelectric–electromagnetic hybrid generator(TEHG)can power sensors and Internet of Things(IoT)nodes in smart agriculture.However,the separation structure of traditional TEHG raises the complexity of form and material,which is harmful to the miniaturization of the device.Herein,a single-material-substrated triboelectric–electromagnetic hybrid generator(SMS-TEHG)based on the flexible magnets is designed to achieve the structural integration of triboelectric nanogenerator(TENG)and electromagnetic generator(EMG).The flexible magnets serve as the electropositive triboelectric materials for TENG and the magnetic materials for EMG,simplifying the structural complexity of TEHG.The open-circuit voltage(VOC)of the TENG and EMG are 187.2 and 9.0 V at 300 rpm,respectively.After 30,000 cycles of stability testing,the VOC of the TENG and EMG retain about 95.6%and 99.3%,respectively.Additionally,the self-powered applications driven by SMS-TEHG in intelligent greenhouse have been successfully demonstrated,such as crop light supplementation,rain monitoring,and wireless temperature and humidity sensing.This work provides a new design for TEHG and possibilities for applying TEHG and IoT in smart agriculture.
