In this study, device modeling and simulation are conducted to explain the effects of each layer thickness and temperature on the performance of ZnO/CdS/CIS thin film solar cells. Also, the thicknesses of the CIS and ...In this study, device modeling and simulation are conducted to explain the effects of each layer thickness and temperature on the performance of ZnO/CdS/CIS thin film solar cells. Also, the thicknesses of the CIS and CdS absorber layers are considered in this work theoretically and experimentally. The calculations of solar cell performances are based on the solutions of the well-known three coupling equations： the continuity equation for holes and electrons and the Poisson equation. Our simulated results show that the efficiency increases by reducing the CdS thickness. Increasing the CIS thickness can increase the efficiency but it needs more materials. The efficiency is more than 19% for a CIS layer with a thickness of 2 μm. CIS nanoparticles are prepared via the polyol route and purified through centrifugation and precipitation processes.Then nanoparticles are dispersed to obtain stable inks that could be directly used for thin-film deposition via spin coating.We also obtain x-ray diffraction（XRD） peak intensities and absorption spectra for CIS experimentally. Finally, absorption spectra for the CdS window layer in several deposition times are investigated experimentally.展开更多
A series of Zn_（1-x）Cd_xO thin films have been fabricated on sapphire by pulsed-laser deposition（PLD）, successfully. To investigate the effect of Cd concentration on structural and optical properties of Zn_（1-x）...A series of Zn_（1-x）Cd_xO thin films have been fabricated on sapphire by pulsed-laser deposition（PLD）, successfully. To investigate the effect of Cd concentration on structural and optical properties of Zn_（1-x）Cd_xO films, x-ray diffraction（XRD）,ultraviolet-visible spectroscopy（UV-vis）, and x-ray photoelectron spectroscopy（XPS） are employed to characterize the films in detail. The XRD pattern indicates that the Zn_（1-x）Cd_xO thin films have high single-orientation of the c axis. The energy bandgap values of ZnCdO thin films decrease from 3.26 eV to 2.98 eV with the increasing Cd concentration（x）according to the（αhν）~2–hν curve. Furthermore, the band offsets of Zn_（1-x）Cd_xO/ZnO heterojunctions are determinated by XPS, indicating that a type-I alignment takes place at the interface and the value of band offset could be tuned by adjusting the Cd concentration.展开更多
In this study,CdS/ZnO(2:3 mol%)thin films are successfully deposited on quartz substrates by using the sputtering technique.Good images on the structural and optical characteristic features of CdS/ZnO thin films befor...In this study,CdS/ZnO(2:3 mol%)thin films are successfully deposited on quartz substrates by using the sputtering technique.Good images on the structural and optical characteristic features of CdS/ZnO thin films before and after annealing are obtained.The CdS/ZnO thin films are annealed respectively at temperatures of 373 K,473 K,and 573 K and the structural features are examined by XRD,ATR-FTIR,and FESEM.The optical properties of CdS/ZnO thin films such as refractive indices,absorption coefficients,optical band gap energy values,Urbach energy values,lattice dielectric constants,and high frequency dielectric constants are determined from spectrophotometer data recorded over the spectral range of 300 nm-2500 nm.Dispersion parameters are investigated by using a single-oscillator model.Photoluminescence spectra of CdS/ZnO thin films show an overall decrease in their intensity peaks after annealing.The third-order nonlinear optical parameter,and nonlinear refractive index are also estimated.展开更多
Microbial infectious are becoming a global threat, which is a reason for rise in mortality of human beings. One of the reasons for this mortality has been the drug resistance in microbes. The drug resistance poses a m...Microbial infectious are becoming a global threat, which is a reason for rise in mortality of human beings. One of the reasons for this mortality has been the drug resistance in microbes. The drug resistance poses a major challenge for effective control of microbial infections, and this threat has prompted us to search for alternative strategy to control the microbial infections. Recently, nanomaterials have emerged as an alternative to conventional platforms because they combine multiple mechanisms of action into one platform due to the distinctive properties of nanosized materials. In the present research we have attempted to synthesize ZnO/CdS nanocomposite for its application as an antimicrobial agent. We have characterized the synthesized nanocomposites by X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The nanocomposites have exhibited good antibacterial property against Gram positive and Gram-negative organisms by virtue of the generation of reactive oxygen species (ROS) inside the cells, as reflected by ruptured appearances in the FESEM micrographs. Apart from antimicrobial activity, it also inhibited biofilm formations in Pseudomonas aeruginosa, a causative organism in lung infection and burn associated infections.展开更多
The surface characteristics of ZnO were synthetically optimized by a self-designed simultaneous etching and W-doping hydrothermal method utilizing as-prepared ZnO nanorod(NR)array films as the template.Benefiting from...The surface characteristics of ZnO were synthetically optimized by a self-designed simultaneous etching and W-doping hydrothermal method utilizing as-prepared ZnO nanorod(NR)array films as the template.Benefiting from the etching and regrowth process and the different structural stabilities of the various faces of ZnO NRs,the uniquely etched and W-doped ZnO(EWZ)nanotube(NT)array films with larger surface area,more active sites and better energy band structure were used to improve the photoelectrochemical(PEC)performance and the loading quality of CdS quantum dots(QDs).On the basis of their better surface characteristics,the CdS QDs were uniformly loaded on EWZ NT array film with a good coverage ratio and interface connection;this effectively improved the light-harvesting ability,charge transportation and separation as well as charge injection efficiency during the PEC reaction.Therefore,all the CdS QD-sensitized EWZ NT array films exhibited significantly enhanced PEC performance.The CdS/EWZ-7 composite films exhibited the optimal photocurrent density with a value of 12 mA·cm^(-2),2.5 times higher than that of conventional CdS/ZnO-7 composite films under the same sensitization times with CdS QDs.The corresponding etching and optimizing mechanisms were also discussed.展开更多
ZnO films with c -axis parallel to the substrate are reported.ZnO films are synthesized by solid-source chemical vapor deposition,a novel CVD technique,using zinc acetate dihydrate (solid) as the source material.The p...ZnO films with c -axis parallel to the substrate are reported.ZnO films are synthesized by solid-source chemical vapor deposition,a novel CVD technique,using zinc acetate dihydrate (solid) as the source material.The properties are characterized by X-ray diffraction,atomic force microscopy and transmission spectra.The parallel oriented ZnO films with mixed orientation for (100) and (110) planes are achieved on glass at the substrate temperature of 200℃ and the source temperature of 280℃,and a qualitative explanation is given for the forming of the mixed orientation.AFM images show that the surface is somewhat rough for the parallel oriented ZnO films.The transmission spectrum exhibits a high transmittance of about 85% in the visible region and shows an optical band gap about 3.25eV at room temperature.展开更多
文摘In this study, device modeling and simulation are conducted to explain the effects of each layer thickness and temperature on the performance of ZnO/CdS/CIS thin film solar cells. Also, the thicknesses of the CIS and CdS absorber layers are considered in this work theoretically and experimentally. The calculations of solar cell performances are based on the solutions of the well-known three coupling equations： the continuity equation for holes and electrons and the Poisson equation. Our simulated results show that the efficiency increases by reducing the CdS thickness. Increasing the CIS thickness can increase the efficiency but it needs more materials. The efficiency is more than 19% for a CIS layer with a thickness of 2 μm. CIS nanoparticles are prepared via the polyol route and purified through centrifugation and precipitation processes.Then nanoparticles are dispersed to obtain stable inks that could be directly used for thin-film deposition via spin coating.We also obtain x-ray diffraction（XRD） peak intensities and absorption spectra for CIS experimentally. Finally, absorption spectra for the CdS window layer in several deposition times are investigated experimentally.
基金supported by the National Natural Science Foundation of China(Grant No.11404302)the Laser Fusion Research Center Funds for Young Talents(Grant No.RCFPD1-2017-9)
文摘A series of Zn_（1-x）Cd_xO thin films have been fabricated on sapphire by pulsed-laser deposition（PLD）, successfully. To investigate the effect of Cd concentration on structural and optical properties of Zn_（1-x）Cd_xO films, x-ray diffraction（XRD）,ultraviolet-visible spectroscopy（UV-vis）, and x-ray photoelectron spectroscopy（XPS） are employed to characterize the films in detail. The XRD pattern indicates that the Zn_（1-x）Cd_xO thin films have high single-orientation of the c axis. The energy bandgap values of ZnCdO thin films decrease from 3.26 eV to 2.98 eV with the increasing Cd concentration（x）according to the（αhν）~2–hν curve. Furthermore, the band offsets of Zn_（1-x）Cd_xO/ZnO heterojunctions are determinated by XPS, indicating that a type-I alignment takes place at the interface and the value of band offset could be tuned by adjusting the Cd concentration.
基金the Deanship of Scientific Research,Taif University,Kingdom of Saudi Arabia(Grant No.1-440-6136).
文摘In this study,CdS/ZnO(2:3 mol%)thin films are successfully deposited on quartz substrates by using the sputtering technique.Good images on the structural and optical characteristic features of CdS/ZnO thin films before and after annealing are obtained.The CdS/ZnO thin films are annealed respectively at temperatures of 373 K,473 K,and 573 K and the structural features are examined by XRD,ATR-FTIR,and FESEM.The optical properties of CdS/ZnO thin films such as refractive indices,absorption coefficients,optical band gap energy values,Urbach energy values,lattice dielectric constants,and high frequency dielectric constants are determined from spectrophotometer data recorded over the spectral range of 300 nm-2500 nm.Dispersion parameters are investigated by using a single-oscillator model.Photoluminescence spectra of CdS/ZnO thin films show an overall decrease in their intensity peaks after annealing.The third-order nonlinear optical parameter,and nonlinear refractive index are also estimated.
文摘Microbial infectious are becoming a global threat, which is a reason for rise in mortality of human beings. One of the reasons for this mortality has been the drug resistance in microbes. The drug resistance poses a major challenge for effective control of microbial infections, and this threat has prompted us to search for alternative strategy to control the microbial infections. Recently, nanomaterials have emerged as an alternative to conventional platforms because they combine multiple mechanisms of action into one platform due to the distinctive properties of nanosized materials. In the present research we have attempted to synthesize ZnO/CdS nanocomposite for its application as an antimicrobial agent. We have characterized the synthesized nanocomposites by X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The nanocomposites have exhibited good antibacterial property against Gram positive and Gram-negative organisms by virtue of the generation of reactive oxygen species (ROS) inside the cells, as reflected by ruptured appearances in the FESEM micrographs. Apart from antimicrobial activity, it also inhibited biofilm formations in Pseudomonas aeruginosa, a causative organism in lung infection and burn associated infections.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61904098 and 11904209)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2019QF018)Higher Education Research and Development Program of Shandong Province,China(Grant No.J18KA242).
文摘The surface characteristics of ZnO were synthetically optimized by a self-designed simultaneous etching and W-doping hydrothermal method utilizing as-prepared ZnO nanorod(NR)array films as the template.Benefiting from the etching and regrowth process and the different structural stabilities of the various faces of ZnO NRs,the uniquely etched and W-doped ZnO(EWZ)nanotube(NT)array films with larger surface area,more active sites and better energy band structure were used to improve the photoelectrochemical(PEC)performance and the loading quality of CdS quantum dots(QDs).On the basis of their better surface characteristics,the CdS QDs were uniformly loaded on EWZ NT array film with a good coverage ratio and interface connection;this effectively improved the light-harvesting ability,charge transportation and separation as well as charge injection efficiency during the PEC reaction.Therefore,all the CdS QD-sensitized EWZ NT array films exhibited significantly enhanced PEC performance.The CdS/EWZ-7 composite films exhibited the optimal photocurrent density with a value of 12 mA·cm^(-2),2.5 times higher than that of conventional CdS/ZnO-7 composite films under the same sensitization times with CdS QDs.The corresponding etching and optimizing mechanisms were also discussed.
文摘ZnO films with c -axis parallel to the substrate are reported.ZnO films are synthesized by solid-source chemical vapor deposition,a novel CVD technique,using zinc acetate dihydrate (solid) as the source material.The properties are characterized by X-ray diffraction,atomic force microscopy and transmission spectra.The parallel oriented ZnO films with mixed orientation for (100) and (110) planes are achieved on glass at the substrate temperature of 200℃ and the source temperature of 280℃,and a qualitative explanation is given for the forming of the mixed orientation.AFM images show that the surface is somewhat rough for the parallel oriented ZnO films.The transmission spectrum exhibits a high transmittance of about 85% in the visible region and shows an optical band gap about 3.25eV at room temperature.
