Water splitting is important to the conversion and storage of renewable energy,but slow kinetics of the oxygen evolution reaction(OER)greatly limits its utility.Here,under visible light illumination,the p-n WO_(3)/SnS...Water splitting is important to the conversion and storage of renewable energy,but slow kinetics of the oxygen evolution reaction(OER)greatly limits its utility.Here,under visible light illumination,the p-n WO_(3)/SnSe_(2)(WS)heterojunction significantly activates OER catalysis of CoFe-layered double hydroxide(CF)/carbon nanotubes(CNTs).Specifically,the catalyst achieves an overpotential of 224 mV at 10 mA cm^(-2)and a small Tafel slope of 47 mV dec^(-1),superior to RuO_(2)and most previously reported transition metal-based OER catalysts.The p-n WS heterojunction shows strong light absorption to produce photogenerated carriers.The photogenerated holes are trapped by CF to suppresses the charge recombination and facilitate charge transfer,which accelerates OER kinetics and boost the activity for the OER.This work highlights the possibility of using heterojunctions to activate OER catalysis and advances the design of energy-efficient catalysts for water oxidation systems using solar energy.展开更多
Recent developments in acceptor–donor–acceptor(A–D–A) type non-fullerene acceptors have led to substantial improvements in bulk-heterojunction polymer solar cells efficiency. The device performance strongly depend...Recent developments in acceptor–donor–acceptor(A–D–A) type non-fullerene acceptors have led to substantial improvements in bulk-heterojunction polymer solar cells efficiency. The device performance strongly depends on photoactive layer morphology, as the molecular packing, donor–acceptor interface and phase separation significantly affect the charge-transfer states and charge carrier dynamics. In this review, we start with a brief introduction of the techniques most effectively utilized to characterize multiphase morphology. Then, we summarize recent progress in A–D–A type acceptors, with the emphasis on understanding the molecular structure–morphology–performance relationships. Finally, an outlook on correlating morphological characteristics with photovoltage losses is presented for further improving device performance.展开更多
The 10 nm p-NiO thin film is prepared by thermal oxidation of Ni onβ-Ga_(2)O_(3)to form NiO/β-Ga_(2)O_(3)p-n heterojunction diodes(HJDs).The NiO/β-Ga_(2)O_(3)HJDs exhibit excellent electrostatic properties,with a h...The 10 nm p-NiO thin film is prepared by thermal oxidation of Ni onβ-Ga_(2)O_(3)to form NiO/β-Ga_(2)O_(3)p-n heterojunction diodes(HJDs).The NiO/β-Ga_(2)O_(3)HJDs exhibit excellent electrostatic properties,with a high breakdown voltage of 465 V,a specific on-resistance(Ron,sp)of 3.39 mΩ·cm^(2),and a turn-on voltage(V on)of 1.85 V,yielding a static Baliga's figure of merit(FOM)of 256 MW/cm^(2).Also,the HJDs have a low turn-on voltage,which reduces conduction loss dramatically,and a rectification ratio of up to 108.Meanwhile,the HJDs'reverse leakage current is essentially unaffected at temperatures below 170?C,and their leakage level may be controlled below 10^(-10)A.This indicates that p-NiO/β-Ga_(2)O_(3)HJDs with good thermal stability and high-temperature operating ability can be a good option for high-performanceβ-Ga_(2)O_(3)power devices.展开更多
The Cu2O/TiO2 p-n heterojunction composite photoelectrodes were prepared by depositing Cu 2 O nanoparticles on the surface of TiO 2 nanotubes via anodic oxidation and constant current deposition.Field emission scannin...The Cu2O/TiO2 p-n heterojunction composite photoelectrodes were prepared by depositing Cu 2 O nanoparticles on the surface of TiO 2 nanotubes via anodic oxidation and constant current deposition.Field emission scanning electron microscopy(SEM)and high-resolution transmission electron microscopy(HRTEM)analyses showed that Cu 2 O nanoparticles not only deposited on the surface of TiO 2 nanotube array,but also on the wall of TiO 2 nanotubes.The Cu 2 O deposition amount could be adjusted by changing the deposition time.The photoelectrochemical cathodic protection(PECCP)performance of the prepared photoelectrodes for 316L stainless steel(SS)was tested under visible light.The constant current deposition time had a signifi cant eff ect on the PECCP performance of Cu 2 O/TiO 2-X photoelectrodes and Cu 2 O/TiO 2-20 had the best PECCP performance for the coupled 316L SS.This was attributed to the appropriate amount and thickness of Cu 2 O to form p-n heterojunctions with TiO 2,in which separation of the photogenerated carriers was accelerated and transfer of the photogenerated electrons to 316L SS for PECCP was facilitated.展开更多
With electron assisted hot filament chemical vapor deposition technology, nanocrystalline diamond films were deposited on polished n-(100)Si wafer surface. The deposited films were characterized and observed by Raman ...With electron assisted hot filament chemical vapor deposition technology, nanocrystalline diamond films were deposited on polished n-(100)Si wafer surface. The deposited films were characterized and observed by Raman spectrum, X-ray diffraction, semiconductor characterization system and Hall effective measurement system. The results show that with EA-HFCVD, not only an undoped nanocrystalline diamond films with high-conductivity (p-type semiconducting) but also a p-n heterojunction diode between the nanocrystalline diamond films and n-Si substrate is fabricated successfully. The p-n heterojunction has smaller forward resistance and bigger positive resistance. The p-n junction effective is evident.展开更多
Improving the separation of photogenerated carriers and suppressing the rapid complication of electron-hole pairs are essential ways to improve photocatalytic hydrogen production activity.The high recombination rate o...Improving the separation of photogenerated carriers and suppressing the rapid complication of electron-hole pairs are essential ways to improve photocatalytic hydrogen production activity.The high recombination rate of the photogenerated carriers is an issue encountered when developing CdS as a promising photocatalytic material.This work allowed to accelerate the separation of photogenerated electrons and holes by loading monoclinicβ-AgVO_(3)on hexagonal CdS nanorods to construct a one-dimensional(1D)/1D p-n heterojunction.The introduction of monoclinicβ-AgVO_(3)with a narrow band gap effectively improves the light absorption of CdS,which is conducive to improving the use of visible light.The integrated electric field of the p-n heterojunction can effectively transfer electrons and holes in the direction suitable to hydrogen evolution.The photoluminescence and electrochemical characterization of the catalysts showed that the p-n heterojunction formed after loadingβ-AgVO_(3)greatly improved the separation efficiency of photocarriers.The hydrogen evolution experiments show that the composite catalyst has good photocatalytic hydrogen evolution capability and stability.The composite catalyst with the best photocatalytic performance was obtained by studyingβ-AgVO_(3)with different loadings.The composite catalyst reached 581.5μmol of hydrogen amount within 5 h,which is 3.8 times higher than that of CdS alone and its apparent quantum efficiency reaches8.02%.The present work provides a possible solution for the development of perovskite and the extensiveness of CdS in photocatalytic hydrogen evolution.展开更多
MoS_(2) is a typical electrocatalyst for hydrogen evolution reaction(HER),but the HER activity is spoilt by intensive adsorption towards H^(*),which requires further improvement.For n-type MoS_(2),the construction of ...MoS_(2) is a typical electrocatalyst for hydrogen evolution reaction(HER),but the HER activity is spoilt by intensive adsorption towards H^(*),which requires further improvement.For n-type MoS_(2),the construction of p-n heterojunction with p-type MoO_(3) can reverse this situation,because inner electronic field in p-n heterojunction can facilitate H^(*) desorption.Based on this hypothesis,p-n heterojunction is built between MoS_(2) and MoO_(3) with polyoxometalate compound as precursor.The obtained MoO_(3)/MoS_(2) exhibits excellent HER activity,which only requires 68 mV to obtain 10 mA/cm^(2).With MoO_(3)/MoS_(2) as cathode material and Zn slice as anode,Zn-H^(+)battery is assembled.Its open circuit voltage achieves 1.11 V with short circuit current 151.4 mA/cm^(2).The peak power density of this Zn-H^(+) battery reaches 47.6 mW/cm^(2).When discharge at 10 mA/cm^(2),the specific capacity and energy density reach 728 mAh/g and 759 Wh/kg.In this process,H_(2) production rate of Zn-H^(+) battery achieves 364μmol/h with Faradic efficiency 97.8%.It realizes H_(2) production and electricity generation simultaneously.展开更多
A visible light-active photoelectrocatalyst,ZnFe-layered double oxide(LDO)/cobalt(II,III)oxide(Co_(3)O_(4))composites were obtained by calcining the Co loaded ZnFe-layered double hydroxide(LDH)prepared by a hydrotherm...A visible light-active photoelectrocatalyst,ZnFe-layered double oxide(LDO)/cobalt(II,III)oxide(Co_(3)O_(4))composites were obtained by calcining the Co loaded ZnFe-layered double hydroxide(LDH)prepared by a hydrothermal and microwave hydrothermal method.The morphological studies revealed that the ZnFe-LDO/Co_(3)O_(4) composites exhibited a flower-like structure comprising Co_(3)O_(4) nanowires and ZnFe-LDO nanosheets.Further,when the mass ratio of Co(NO_(3))_(2)·6H_(2)O/LDH was 1:1.8 and the calcination temperature was 550℃,the ZnFe-LDO/Co_(3)O_(4) composite exhibited 93.3%degradation efficiency for methylene blue(MB)at the applied voltage of 1.0 V under visible light after 3 h.Furthermore,the Mott-Schottky model experiments showed that the formation of a p-n heterojunction between ZnFe-LDO and Co_(3)O_(4) could effectively inhibit the recombination of electrons and holes in the photoelectrocatalytic process.Meanwhile,free radical scavenging experiments showed that the active radicals of⋅OH played an important role in the degradation of MB.Therefore,the photoelectrocatalytic effect of ZnFe-LDO/Co_(3)O_(4) provides a simple and effective strategy for the removal of organic pollutants.展开更多
基金the National Natural Science Foundation of China(No.41807213)the Hydrogeo-logical Survey Project of Huangshui River(No.DD20190331).
文摘Water splitting is important to the conversion and storage of renewable energy,but slow kinetics of the oxygen evolution reaction(OER)greatly limits its utility.Here,under visible light illumination,the p-n WO_(3)/SnSe_(2)(WS)heterojunction significantly activates OER catalysis of CoFe-layered double hydroxide(CF)/carbon nanotubes(CNTs).Specifically,the catalyst achieves an overpotential of 224 mV at 10 mA cm^(-2)and a small Tafel slope of 47 mV dec^(-1),superior to RuO_(2)and most previously reported transition metal-based OER catalysts.The p-n WS heterojunction shows strong light absorption to produce photogenerated carriers.The photogenerated holes are trapped by CF to suppresses the charge recombination and facilitate charge transfer,which accelerates OER kinetics and boost the activity for the OER.This work highlights the possibility of using heterojunctions to activate OER catalysis and advances the design of energy-efficient catalysts for water oxidation systems using solar energy.
基金support by Research Grants Council of Hong Kong(Grant Nos.15246816 and 15218517)the funding for Project of Strategic Importance provided by the Hong Kong Polytechnic University(Project Code:1-ZE29)the Shenzhen Science and Technology Innovation Commission(Project no.JCYJ20170413154602102)
文摘Recent developments in acceptor–donor–acceptor(A–D–A) type non-fullerene acceptors have led to substantial improvements in bulk-heterojunction polymer solar cells efficiency. The device performance strongly depends on photoactive layer morphology, as the molecular packing, donor–acceptor interface and phase separation significantly affect the charge-transfer states and charge carrier dynamics. In this review, we start with a brief introduction of the techniques most effectively utilized to characterize multiphase morphology. Then, we summarize recent progress in A–D–A type acceptors, with the emphasis on understanding the molecular structure–morphology–performance relationships. Finally, an outlook on correlating morphological characteristics with photovoltage losses is presented for further improving device performance.
基金the Technology Innovation and Application Demonstration Key Project of Chongqing Municipality(cstc2019jszx-zdztzxX0005)the Technology Innovation and Application Demonstration Key Project of Chongqing Municipality(cstc2020jscx-gksbX0011)+1 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202100614)the Natural Science Foundation of Chongqing(cstc2021jcyj-bshX0146)。
文摘The 10 nm p-NiO thin film is prepared by thermal oxidation of Ni onβ-Ga_(2)O_(3)to form NiO/β-Ga_(2)O_(3)p-n heterojunction diodes(HJDs).The NiO/β-Ga_(2)O_(3)HJDs exhibit excellent electrostatic properties,with a high breakdown voltage of 465 V,a specific on-resistance(Ron,sp)of 3.39 mΩ·cm^(2),and a turn-on voltage(V on)of 1.85 V,yielding a static Baliga's figure of merit(FOM)of 256 MW/cm^(2).Also,the HJDs have a low turn-on voltage,which reduces conduction loss dramatically,and a rectification ratio of up to 108.Meanwhile,the HJDs'reverse leakage current is essentially unaffected at temperatures below 170?C,and their leakage level may be controlled below 10^(-10)A.This indicates that p-NiO/β-Ga_(2)O_(3)HJDs with good thermal stability and high-temperature operating ability can be a good option for high-performanceβ-Ga_(2)O_(3)power devices.
基金Supported by the National Natural Science Foundation of China(Nos.41576114,41676069)the State Key Laboratory for Marine Corrosion and Protection,Luoyang Ship Material Research Institute,China(No.614290101011703)the Qingdao Innovative Leading Talent Foundation(No.15-10-3-15-(39)-zch)。
文摘The Cu2O/TiO2 p-n heterojunction composite photoelectrodes were prepared by depositing Cu 2 O nanoparticles on the surface of TiO 2 nanotubes via anodic oxidation and constant current deposition.Field emission scanning electron microscopy(SEM)and high-resolution transmission electron microscopy(HRTEM)analyses showed that Cu 2 O nanoparticles not only deposited on the surface of TiO 2 nanotube array,but also on the wall of TiO 2 nanotubes.The Cu 2 O deposition amount could be adjusted by changing the deposition time.The photoelectrochemical cathodic protection(PECCP)performance of the prepared photoelectrodes for 316L stainless steel(SS)was tested under visible light.The constant current deposition time had a signifi cant eff ect on the PECCP performance of Cu 2 O/TiO 2-X photoelectrodes and Cu 2 O/TiO 2-20 had the best PECCP performance for the coupled 316L SS.This was attributed to the appropriate amount and thickness of Cu 2 O to form p-n heterojunctions with TiO 2,in which separation of the photogenerated carriers was accelerated and transfer of the photogenerated electrons to 316L SS for PECCP was facilitated.
基金Project supported by the National Natural Science Foundation of China (60277024)
文摘With electron assisted hot filament chemical vapor deposition technology, nanocrystalline diamond films were deposited on polished n-(100)Si wafer surface. The deposited films were characterized and observed by Raman spectrum, X-ray diffraction, semiconductor characterization system and Hall effective measurement system. The results show that with EA-HFCVD, not only an undoped nanocrystalline diamond films with high-conductivity (p-type semiconducting) but also a p-n heterojunction diode between the nanocrystalline diamond films and n-Si substrate is fabricated successfully. The p-n heterojunction has smaller forward resistance and bigger positive resistance. The p-n junction effective is evident.
基金financially supported by the National Natural Science Foundation of China(Nos.22062001,21975084)。
文摘Improving the separation of photogenerated carriers and suppressing the rapid complication of electron-hole pairs are essential ways to improve photocatalytic hydrogen production activity.The high recombination rate of the photogenerated carriers is an issue encountered when developing CdS as a promising photocatalytic material.This work allowed to accelerate the separation of photogenerated electrons and holes by loading monoclinicβ-AgVO_(3)on hexagonal CdS nanorods to construct a one-dimensional(1D)/1D p-n heterojunction.The introduction of monoclinicβ-AgVO_(3)with a narrow band gap effectively improves the light absorption of CdS,which is conducive to improving the use of visible light.The integrated electric field of the p-n heterojunction can effectively transfer electrons and holes in the direction suitable to hydrogen evolution.The photoluminescence and electrochemical characterization of the catalysts showed that the p-n heterojunction formed after loadingβ-AgVO_(3)greatly improved the separation efficiency of photocarriers.The hydrogen evolution experiments show that the composite catalyst has good photocatalytic hydrogen evolution capability and stability.The composite catalyst with the best photocatalytic performance was obtained by studyingβ-AgVO_(3)with different loadings.The composite catalyst reached 581.5μmol of hydrogen amount within 5 h,which is 3.8 times higher than that of CdS alone and its apparent quantum efficiency reaches8.02%.The present work provides a possible solution for the development of perovskite and the extensiveness of CdS in photocatalytic hydrogen evolution.
基金supported by National Natural Science Foundation of China(No.22171039)Fundamental Research Funds for the Central University(No.N2025035)。
文摘MoS_(2) is a typical electrocatalyst for hydrogen evolution reaction(HER),but the HER activity is spoilt by intensive adsorption towards H^(*),which requires further improvement.For n-type MoS_(2),the construction of p-n heterojunction with p-type MoO_(3) can reverse this situation,because inner electronic field in p-n heterojunction can facilitate H^(*) desorption.Based on this hypothesis,p-n heterojunction is built between MoS_(2) and MoO_(3) with polyoxometalate compound as precursor.The obtained MoO_(3)/MoS_(2) exhibits excellent HER activity,which only requires 68 mV to obtain 10 mA/cm^(2).With MoO_(3)/MoS_(2) as cathode material and Zn slice as anode,Zn-H^(+)battery is assembled.Its open circuit voltage achieves 1.11 V with short circuit current 151.4 mA/cm^(2).The peak power density of this Zn-H^(+) battery reaches 47.6 mW/cm^(2).When discharge at 10 mA/cm^(2),the specific capacity and energy density reach 728 mAh/g and 759 Wh/kg.In this process,H_(2) production rate of Zn-H^(+) battery achieves 364μmol/h with Faradic efficiency 97.8%.It realizes H_(2) production and electricity generation simultaneously.
文摘A visible light-active photoelectrocatalyst,ZnFe-layered double oxide(LDO)/cobalt(II,III)oxide(Co_(3)O_(4))composites were obtained by calcining the Co loaded ZnFe-layered double hydroxide(LDH)prepared by a hydrothermal and microwave hydrothermal method.The morphological studies revealed that the ZnFe-LDO/Co_(3)O_(4) composites exhibited a flower-like structure comprising Co_(3)O_(4) nanowires and ZnFe-LDO nanosheets.Further,when the mass ratio of Co(NO_(3))_(2)·6H_(2)O/LDH was 1:1.8 and the calcination temperature was 550℃,the ZnFe-LDO/Co_(3)O_(4) composite exhibited 93.3%degradation efficiency for methylene blue(MB)at the applied voltage of 1.0 V under visible light after 3 h.Furthermore,the Mott-Schottky model experiments showed that the formation of a p-n heterojunction between ZnFe-LDO and Co_(3)O_(4) could effectively inhibit the recombination of electrons and holes in the photoelectrocatalytic process.Meanwhile,free radical scavenging experiments showed that the active radicals of⋅OH played an important role in the degradation of MB.Therefore,the photoelectrocatalytic effect of ZnFe-LDO/Co_(3)O_(4) provides a simple and effective strategy for the removal of organic pollutants.
