Titanium-based semiconductors are known for their high chemical stability and suitable band gap widths.However,the conventional experimental screening methods are inefficient due to the wide variety of materials.To sp...Titanium-based semiconductors are known for their high chemical stability and suitable band gap widths.However,the conventional experimental screening methods are inefficient due to the wide variety of materials.To speed up the selection process,this work focuses on interpretable feature learning and band gap prediction for titanium-based semiconductors.First,titanium compounds were selected from the Materials Project database by machine learning,and elemental features were extracted using the Magpie descriptors.Then,principal component analysis(PCA)was applied to reduce the data dimensionality,creating a representative dataset.Meantime,heatmaps and SHAP(SHapley Additive exPlanations)methods were used to demonstrate the influence of key features such as electronegativity,covalent radius,period number,and unit cell volume on the bandgap,understanding the relationship between the material’s properties and performance.After comparing different machine learning models,including Random Forest(RF),Support Vector Machines(SVM),Linear Regression(LR),and Gradient Boosting Regression(GBR),the RF was found to be the most accurate for band gap prediction.Finally,the model performance was improved through parameter tuning,showing high accuracy.These findings provide strong data support and design guidance for the development of materials in fields like photocatalysis and solar cells.展开更多
Efficient photo-patterning of polymer semiconductors with cross-linkers has emerged as a promising route to fabricate organic integrated circuits via all-solution processing techniques.Herein,we report a new four-arme...Efficient photo-patterning of polymer semiconductors with cross-linkers has emerged as a promising route to fabricate organic integrated circuits via all-solution processing techniques.Herein,we report a new four-armed diazo-based oligomer photo-crosslinker 2DPP4N_(2)for the patterning of semiconducting polymers by UV light-induced crossing-linking reaction.After blending 2DPP4N_(2)with polymer semiconductors such as PDPP4T(p-type),PDPP3T(ambipolar)and N2200(n-type),we prepared various patterns with a resolution of 6μm by irradiating through a photo-mask with 254 nm UV light for 160 s.Notably,the interchain packing and surface morphology remained nearly unchanged after photo-patterning,as characterized by atomic force microscopy(AFM)and grazing incidence wide-angle X-ray scattering(GIWAXS).Consequently,the charge transport property of the patterned thin film was largely maintained in comparison to that of its pristine thin film.These results reveal that 2DPP4N_(2)is a viable and promising candidate for application in all-solution-processable flexible integrated electronic devices.展开更多
Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models...Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models for three-dimensional(3D)PSC contact problems are still scarce,especially for conductive indenters.This work develops a semi-analytical framework to study the 3D frictionless contact between a conductive indenter and a PSC half-space.Fundamental solutions under a unit force and a unit electric charge are derived,and the corresponding frequency response functions are combined with a discrete convolution-fast Fourier transform(DC-FFT)algorithm to achieve an efficient semi-analytical contact model.The numerical results demonstrate that an increase in the surface charge density reduces the indentation pressure and modifies the electric potential distribution.A higher steady carrier concentration enhances the screening effect,suppresses the electromechanical coupling,and shifts the system response toward purely elastic behaviors.The sensitivity analysis shows that the indentation depth is dominated by the elastic constants,while the electric potential is mainly affected by the piezoelectric coefficient.Although the analysis is carried out with spherical indenters,the model is not limited to a specific indenter shape.It provides an effective tool for investigating complex 3D PSC contact problems and offers useful insights into the design of PSC materials-based devices.展开更多
Amongst all the scientific achievements in the 20th century,no single invention has impacted our lives more profoundly than the transistors,or semiconductors.Since we entered the era of computing in the 1960s,we have ...Amongst all the scientific achievements in the 20th century,no single invention has impacted our lives more profoundly than the transistors,or semiconductors.Since we entered the era of computing in the 1960s,we have witnessed a number of notable transformational shifts such as the transition to personal computers and then mobile era.展开更多
Regioselevtive functionalization of perylene diimides(PDIs)at bay area often requires multistep synthesis and strenuous recrystallization.Direct bromination of perylene diimides only afford the 1,6 and 1,7-regioisomer...Regioselevtive functionalization of perylene diimides(PDIs)at bay area often requires multistep synthesis and strenuous recrystallization.Direct bromination of perylene diimides only afford the 1,6 and 1,7-regioisomers.More importantly,the 1,6-dibromo regioisomers could only be separated by preparative HPLC.Herein,we report a promising strategy for constructing Janus backbone of BN-doped perylene diimide derivatives.This Janus-type configuration results in the unique regioselective functionalization of BN-JPDIs,which yields exclusively the 1,6-regioisomers.Further investigation shows that the Janus-type configuration leads to a net dipole moment of 1.94 D and intramolecular charge transfer,which causes substantial changes on the optoelectronic properties.Moreover,the single crystal organic field-effect transistors based on BN-JPDIs exhibit electron mobilities up to 0.57 cm^(2)V^(-1)s^(-1),showcasing their potential as versatile building block towards high-performance n-type organic semiconductors.展开更多
Flexoelectricity,an electromechanical coupling between strain gradient and electrical polarization in dielectrics or semiconductors,has attracted significant scientific interest.It is reported that large flexoelectric...Flexoelectricity,an electromechanical coupling between strain gradient and electrical polarization in dielectrics or semiconductors,has attracted significant scientific interest.It is reported that large flexoelectric behaviors can be obtained at the nanoscale because of the size effect.However,the flexoelectric responses of centrosymmetric semiconductors(CSs)are extremely weak under a conventional beam-bending approach,owing to weak flexoelectric coefficients and small strain gradients.The flexoelectric-like effect is an enhanced electromechanical effect coupling the flexoelectricity and piezoelectricity.In this paper,a composite structure consisting of piezoelectric dielectric layers and a CS layer is proposed.The electromechanical response of the CS is significantly enhanced via antisymmetric piezoelectric polarization.Consequently,the cross-scale mechanically tuned carrier distribution in the semiconductor is realized.Meanwhile,the significant size dependence of the electromechanical fields in the semiconductor is demonstrated.The flexoelectronics suppression is found when the semiconductor thickness reaches a critical size(0.8μm).In addition,the first-order carrier density of the composite structure under local loads is illustrated.Our results can suggest the structural design for flexoelectric semiconductor devices.展开更多
Doping plays a pivotal role in enhancing the performance of organic semiconductors(OSCs)for advanced optoelectronic and thermoelectric applications.In this study,we systematically investigated the doping performance a...Doping plays a pivotal role in enhancing the performance of organic semiconductors(OSCs)for advanced optoelectronic and thermoelectric applications.In this study,we systematically investigated the doping performance and applicability of the ionic dopant 4-isopropyl-4′-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate)(DPI-TPFB)as a p-dopant for OSCs.Using the p-type OSC PBBT-2T as a model system,we demonstrated that DPI-TPFB shows significant doping effect,as confirmed by ESR spectra,ultraviolet-visible-near-infrared(UV-vis-NIR)absorption,and work function analysis,and enhances the electronic conductivity of PBBT-2T films by over four orders of magnitude.Furthermore,DPI-TPFB exhibited broad doping applicability,effectively doping various p-type OSCs and even imparting p-type characteristics to the n-type OSC N2200,transforming its intrinsic n-type behavior into p-type.The application of DPI-TPFB-doped PBBT-2T films in organic thermoelectric devices(OTEs)was also explored,achieving a power factor of approximately 10μW·m^(-1)·K^(-2).These findings highlight the potential of DPI-TPFB as a versatile and efficient dopant for integration into organic optoelectronic and thermoelectric devices.展开更多
The optical absorption spectra of the covalent crystals ZnX(X=S,Se) doped with Co 2+ are studied using the double covalency factors,which considers the anisotropic distortion of e g and t 2g orbits for d el...The optical absorption spectra of the covalent crystals ZnX(X=S,Se) doped with Co 2+ are studied using the double covalency factors,which considers the anisotropic distortion of e g and t 2g orbits for d electron.When the paramagnetic g factor is calculated,the contributions of the spin orbit coupling from the ligand ions are taken into account besides that from the central ion,which is the double ξ model.The calculated results indicate that the theoretical values coincide with the experimental values very well.This suggests that the method presented in this paper could be more valid to some strongly covalent crystals.展开更多
In response to the global energy crisis and environmental challenges,photocatalytic hydrogen(H_(2))production has emerged as a sustainable alternative toward clean energy conversion.Among diverse photocatalysts invest...In response to the global energy crisis and environmental challenges,photocatalytic hydrogen(H_(2))production has emerged as a sustainable alternative toward clean energy conversion.Among diverse photocatalysts investigated,TiO_(2)-based nanomaterials have attracted significant attention due to their unique physicochemical properties,such as high chemical stability,strong redox capacity and tunable electronic structures,along with high cost-effectiveness.Extensive research on TiO_(2)-based photocatalysts proves their enormous potential in the field of H2 production.This timely and critical review explores the recent advances in TiO_(2)-based photocatalysts,discussing their distinctive advantages and synthesis methods in photocatalytic H2 production.Modification strategies,such as elemental doping(e.g.,precious metals,non-precious metals and non-metals),morphology engineering and composite formation,are summarised to improve photocatalytic efficiency.Advanced in/ex situ characterization techniques employed to probe photocatalytic mechanisms are also highlighted.Finally,major challenges,such as limited visible-light activity and charge recombination,are outlined,with perspectives on emerging TiO_(2)-based nanomaterials and design strategies to overcome current bottlenecks.And the research focus in the future is prospected,such as atomic interface engineering,machine learning auxiliary material design and large-scale preparation technology.This work aims to provide insights into the rational design of TiO_(2)-based photocatalysts for next-generation H2 production systems.展开更多
文摘Titanium-based semiconductors are known for their high chemical stability and suitable band gap widths.However,the conventional experimental screening methods are inefficient due to the wide variety of materials.To speed up the selection process,this work focuses on interpretable feature learning and band gap prediction for titanium-based semiconductors.First,titanium compounds were selected from the Materials Project database by machine learning,and elemental features were extracted using the Magpie descriptors.Then,principal component analysis(PCA)was applied to reduce the data dimensionality,creating a representative dataset.Meantime,heatmaps and SHAP(SHapley Additive exPlanations)methods were used to demonstrate the influence of key features such as electronegativity,covalent radius,period number,and unit cell volume on the bandgap,understanding the relationship between the material’s properties and performance.After comparing different machine learning models,including Random Forest(RF),Support Vector Machines(SVM),Linear Regression(LR),and Gradient Boosting Regression(GBR),the RF was found to be the most accurate for band gap prediction.Finally,the model performance was improved through parameter tuning,showing high accuracy.These findings provide strong data support and design guidance for the development of materials in fields like photocatalysis and solar cells.
基金supported by the National Natural Science Foundation of China(No.22205242)。
文摘Efficient photo-patterning of polymer semiconductors with cross-linkers has emerged as a promising route to fabricate organic integrated circuits via all-solution processing techniques.Herein,we report a new four-armed diazo-based oligomer photo-crosslinker 2DPP4N_(2)for the patterning of semiconducting polymers by UV light-induced crossing-linking reaction.After blending 2DPP4N_(2)with polymer semiconductors such as PDPP4T(p-type),PDPP3T(ambipolar)and N2200(n-type),we prepared various patterns with a resolution of 6μm by irradiating through a photo-mask with 254 nm UV light for 160 s.Notably,the interchain packing and surface morphology remained nearly unchanged after photo-patterning,as characterized by atomic force microscopy(AFM)and grazing incidence wide-angle X-ray scattering(GIWAXS).Consequently,the charge transport property of the patterned thin film was largely maintained in comparison to that of its pristine thin film.These results reveal that 2DPP4N_(2)is a viable and promising candidate for application in all-solution-processable flexible integrated electronic devices.
基金Project supported by the National Natural Science Foundation of China(No.12402113)the Sichuan Science and Technology Program(No.2024NSFSC0037)。
文摘Piezoelectric semiconductor(PSC)materials exhibit strong electromechanical coupling affected by free carriers,which makes their contact behavior essential for sensors,actuators,and electronic devices.Analytical models for three-dimensional(3D)PSC contact problems are still scarce,especially for conductive indenters.This work develops a semi-analytical framework to study the 3D frictionless contact between a conductive indenter and a PSC half-space.Fundamental solutions under a unit force and a unit electric charge are derived,and the corresponding frequency response functions are combined with a discrete convolution-fast Fourier transform(DC-FFT)algorithm to achieve an efficient semi-analytical contact model.The numerical results demonstrate that an increase in the surface charge density reduces the indentation pressure and modifies the electric potential distribution.A higher steady carrier concentration enhances the screening effect,suppresses the electromechanical coupling,and shifts the system response toward purely elastic behaviors.The sensitivity analysis shows that the indentation depth is dominated by the elastic constants,while the electric potential is mainly affected by the piezoelectric coefficient.Although the analysis is carried out with spherical indenters,the model is not limited to a specific indenter shape.It provides an effective tool for investigating complex 3D PSC contact problems and offers useful insights into the design of PSC materials-based devices.
文摘Amongst all the scientific achievements in the 20th century,no single invention has impacted our lives more profoundly than the transistors,or semiconductors.Since we entered the era of computing in the 1960s,we have witnessed a number of notable transformational shifts such as the transition to personal computers and then mobile era.
基金support from the National Natural Science Foundation of China(Nos.22071007,22020102001,22335002)the National Key R&D Program of China(No.2022YFB3602802)+3 种基金Beijing Natural Science Foundation(No.Z220025)the National Facility for Protein Science in Shanghai,Shanghai Advanced Research Institute,CAS,for providing technical support in X-ray diffraction data collectionthe High-Performance Computing Platform of Peking University for supporting the computational workthe support of BMS Junior Fellow program。
文摘Regioselevtive functionalization of perylene diimides(PDIs)at bay area often requires multistep synthesis and strenuous recrystallization.Direct bromination of perylene diimides only afford the 1,6 and 1,7-regioisomers.More importantly,the 1,6-dibromo regioisomers could only be separated by preparative HPLC.Herein,we report a promising strategy for constructing Janus backbone of BN-doped perylene diimide derivatives.This Janus-type configuration results in the unique regioselective functionalization of BN-JPDIs,which yields exclusively the 1,6-regioisomers.Further investigation shows that the Janus-type configuration leads to a net dipole moment of 1.94 D and intramolecular charge transfer,which causes substantial changes on the optoelectronic properties.Moreover,the single crystal organic field-effect transistors based on BN-JPDIs exhibit electron mobilities up to 0.57 cm^(2)V^(-1)s^(-1),showcasing their potential as versatile building block towards high-performance n-type organic semiconductors.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB2011400)the National Natural Science Foundation of China(Grant No.52375081).
文摘Flexoelectricity,an electromechanical coupling between strain gradient and electrical polarization in dielectrics or semiconductors,has attracted significant scientific interest.It is reported that large flexoelectric behaviors can be obtained at the nanoscale because of the size effect.However,the flexoelectric responses of centrosymmetric semiconductors(CSs)are extremely weak under a conventional beam-bending approach,owing to weak flexoelectric coefficients and small strain gradients.The flexoelectric-like effect is an enhanced electromechanical effect coupling the flexoelectricity and piezoelectricity.In this paper,a composite structure consisting of piezoelectric dielectric layers and a CS layer is proposed.The electromechanical response of the CS is significantly enhanced via antisymmetric piezoelectric polarization.Consequently,the cross-scale mechanically tuned carrier distribution in the semiconductor is realized.Meanwhile,the significant size dependence of the electromechanical fields in the semiconductor is demonstrated.The flexoelectronics suppression is found when the semiconductor thickness reaches a critical size(0.8μm).In addition,the first-order carrier density of the composite structure under local loads is illustrated.Our results can suggest the structural design for flexoelectric semiconductor devices.
基金supported by the Fundamental Research Program of Shanxi Province(Nos.202303021212159 and 202303021222190)the National Natural Science Foundation of China(No.62222403)+2 种基金the Higher Education Institutions Science and Technology Innovation Program of Shanxi Province(No.2023L160)the Scientific Research Fund of Hunan Provincial Education Department(No.23B0842)the Natural Science Foundation of Shanxi Normal University(Nos.JCYJ2024017 and JCYJ2023015)。
文摘Doping plays a pivotal role in enhancing the performance of organic semiconductors(OSCs)for advanced optoelectronic and thermoelectric applications.In this study,we systematically investigated the doping performance and applicability of the ionic dopant 4-isopropyl-4′-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate)(DPI-TPFB)as a p-dopant for OSCs.Using the p-type OSC PBBT-2T as a model system,we demonstrated that DPI-TPFB shows significant doping effect,as confirmed by ESR spectra,ultraviolet-visible-near-infrared(UV-vis-NIR)absorption,and work function analysis,and enhances the electronic conductivity of PBBT-2T films by over four orders of magnitude.Furthermore,DPI-TPFB exhibited broad doping applicability,effectively doping various p-type OSCs and even imparting p-type characteristics to the n-type OSC N2200,transforming its intrinsic n-type behavior into p-type.The application of DPI-TPFB-doped PBBT-2T films in organic thermoelectric devices(OTEs)was also explored,achieving a power factor of approximately 10μW·m^(-1)·K^(-2).These findings highlight the potential of DPI-TPFB as a versatile and efficient dopant for integration into organic optoelectronic and thermoelectric devices.
文摘The optical absorption spectra of the covalent crystals ZnX(X=S,Se) doped with Co 2+ are studied using the double covalency factors,which considers the anisotropic distortion of e g and t 2g orbits for d electron.When the paramagnetic g factor is calculated,the contributions of the spin orbit coupling from the ligand ions are taken into account besides that from the central ion,which is the double ξ model.The calculated results indicate that the theoretical values coincide with the experimental values very well.This suggests that the method presented in this paper could be more valid to some strongly covalent crystals.
文摘In response to the global energy crisis and environmental challenges,photocatalytic hydrogen(H_(2))production has emerged as a sustainable alternative toward clean energy conversion.Among diverse photocatalysts investigated,TiO_(2)-based nanomaterials have attracted significant attention due to their unique physicochemical properties,such as high chemical stability,strong redox capacity and tunable electronic structures,along with high cost-effectiveness.Extensive research on TiO_(2)-based photocatalysts proves their enormous potential in the field of H2 production.This timely and critical review explores the recent advances in TiO_(2)-based photocatalysts,discussing their distinctive advantages and synthesis methods in photocatalytic H2 production.Modification strategies,such as elemental doping(e.g.,precious metals,non-precious metals and non-metals),morphology engineering and composite formation,are summarised to improve photocatalytic efficiency.Advanced in/ex situ characterization techniques employed to probe photocatalytic mechanisms are also highlighted.Finally,major challenges,such as limited visible-light activity and charge recombination,are outlined,with perspectives on emerging TiO_(2)-based nanomaterials and design strategies to overcome current bottlenecks.And the research focus in the future is prospected,such as atomic interface engineering,machine learning auxiliary material design and large-scale preparation technology.This work aims to provide insights into the rational design of TiO_(2)-based photocatalysts for next-generation H2 production systems.
