The tribological behaviors of Cu-15Ni-8Sn/graphite composites with the graphite content of 38 vol.%against AISI321 stainless steel under dry-sliding,deionized water and sea water were investigated on a block-on-ring c...The tribological behaviors of Cu-15Ni-8Sn/graphite composites with the graphite content of 38 vol.%against AISI321 stainless steel under dry-sliding,deionized water and sea water were investigated on a block-on-ring configuration.The results indicated that the friction coefficient was the lowest under dry-sliding,and the highest in deionized water.The wear rate decreased to reach the minimum value of 1.39×10-15 m3/(N·m)in sea water and in deionized water,it increased to the maximum value of 5.56×10-15 m3/(N·m).The deionized water hindered the formation of tribo-oxide layer and lubricating film,which resulted in the largest friction coefficient and wear rate.In sea water,however,the corrosion products comprised of oxides,hydroxides and chlorides were found on the worn surface,and the compacted layer composed of corrosion products and graphite played an important role in keeping the excellent wear resistance.It was elucidated that the tribological behaviors of Cu-15Ni-8Sn/graphite composite were powerful influenced by the friction environments.展开更多
The photovoltaic performance of perovskite solar cells(PSCs)can be improved by utilizing efficient front contact.However,it has always been a significant challenge for fabricating high-quality,scalable,controllable,an...The photovoltaic performance of perovskite solar cells(PSCs)can be improved by utilizing efficient front contact.However,it has always been a significant challenge for fabricating high-quality,scalable,controllable,and cost-effective front contact.This study proposes a realistic multi-layer front contact design to realize efficient single-junction PSCs and perovskite/perovskite tandem solar cells(TSCs).As a critical part of the front contact,we prepared a highly compact titanium oxide(TiO2)film by industrially viable Spray Pyrolysis Deposition(SPD),which acts as a potential electron transport layer(ETL)for the fabrication of PSCs.Optimization and reproducibility of the TiO2 ETL were discreetly investigated while fabricating a set of planar PSCs.As the front contact has a significant influence on the optoelectronic properties of PSCs,hence,we investigated the optics and electrical effects of PSCs by three-dimensional(3D)finite-difference time-domain(FDTD)and finite element method(FEM)rigorous simulations.The investigation allows us to compare experimental results with the outcome from simulations.Furthermore,an optimized single-junction PSC is designed to enhance the energy conversion efficiency(ECE)by>30% compared to the planar reference PSC.Finally,the study has been progressed to the realization of all-perovskite TSC that can reach the ECE,exceeding 30%.Detailed guidance for the completion of high-performance PSCs is provided.展开更多
Perovskite solar cells are known to have a power conversion efficiency dependent on subtle variation in chemical composition and crystal and microstructures of materials,processing conditions,and device fabrication pr...Perovskite solar cells are known to have a power conversion efficiency dependent on subtle variation in chemical composition and crystal and microstructures of materials,processing conditions,and device fabrication procedures and conditions.The present work demonstrates such strong dependence of power conversion efficiency on a TiO_2 film made of the same sol with various aging time.A dense and conformal TiO_2 film was prepared by sol-gel method,and the influences of its surface morphology and thickness on performance of perovskite solar cells have been investigated.The surface morphology and thickness of the TiO_2 film were tuned by adjusting the aging time of sol,resulting in enhanced short-circuit current density and fill factor of the perovskite solar cells due to increased coverage and roughness of perovskite films,light refraction,and effective charge recombination blocking effect,which were verified by means of the light absorption spectra,photoluminescence of perovskite films with and without hole transport layer,cyclic voltammogram,and electrochemical impedance spectra.The cells with a dense and conformal TiO_2 compact layer derived from the sol aged for 4 h exhibit a power conversion efficiency of 15.7%,50% higher than the efficiency based on TiO_2 layer derived from 0 h aging sol and 3 times of the efficiency with TiO_2 layer made from 8 h aged sol.展开更多
A hydrolysis process was applied to prepare the compact TiO2 layer using the fresh metastable TIC14 isopropanol/water solution as the precursor solution for the preparation of the inorganic-organic hybrid heterojuncti...A hydrolysis process was applied to prepare the compact TiO2 layer using the fresh metastable TIC14 isopropanol/water solution as the precursor solution for the preparation of the inorganic-organic hybrid heterojunction perovskite solar cells. The optimal compact TiO2 layer prepared from the aqueous solution of 2 mol/L TiCl4 diluted in isopropanol at 1 ： 3 by volume as precursor solution was uniform and with a film thickness of 126 nm. The corresponding perovskite solar cell gave a photovoltaic conversion efficiency of 10.61%.展开更多
The tungsten trioxide（WO3） thin films were firstly prepared by spin-coating-pyrolysis methods using the ammonium metatungstate（（NH4）6H2W12O40）DMF/water solution, and successfully applied as the efficient compact...The tungsten trioxide（WO3） thin films were firstly prepared by spin-coating-pyrolysis methods using the ammonium metatungstate（（NH4）6H2W12O40）DMF/water solution, and successfully applied as the efficient compact layers for the planar perovskite solar cells. The influence of the WO3 film thickness and the rinsing treatment of CH_3NH_3 PbI_3 thin film with isopropanol on the photovoltaic performance of the corresponding perovskite solar cells was systematically investigated. The results revealed that the perovskite solar cell with a 62 nm thick WO3 compact layer achieved a photoelectric conversion efficiency of 5.72%, with a short circuit photocurrent density of 17.39 mA/cm^2, an open circuit voltage of 0.58 V and a fill factor of 0.57. The photoelectric conversion efficiency was improved from 5.72% to 7.04% by the isopropanol rinsing treatment.展开更多
基金Project(51674304) supported by the National Natural Science Foundation of ChinaProject(19B430013) supported by the Key Scientific Research Projects of Higher Education Institutions in Henan Province,ChinaProject(2017BSJJ013) supported by the Doctor Research Foundation of Zhengzhou University of Light Industry,China
文摘The tribological behaviors of Cu-15Ni-8Sn/graphite composites with the graphite content of 38 vol.%against AISI321 stainless steel under dry-sliding,deionized water and sea water were investigated on a block-on-ring configuration.The results indicated that the friction coefficient was the lowest under dry-sliding,and the highest in deionized water.The wear rate decreased to reach the minimum value of 1.39×10-15 m3/(N·m)in sea water and in deionized water,it increased to the maximum value of 5.56×10-15 m3/(N·m).The deionized water hindered the formation of tribo-oxide layer and lubricating film,which resulted in the largest friction coefficient and wear rate.In sea water,however,the corrosion products comprised of oxides,hydroxides and chlorides were found on the worn surface,and the compacted layer composed of corrosion products and graphite played an important role in keeping the excellent wear resistance.It was elucidated that the tribological behaviors of Cu-15Ni-8Sn/graphite composite were powerful influenced by the friction environments.
基金supported in part by the Research and Study Project of Tokai University General Research Organization and by the Grant-in-Aid for Scientific Research Grant Number 20H02838the Universiti Kebangsaan Malaysia for supporting this study through FRGS/1/2017/TK07/UKM/02/9 Grantsupported by the Research Grants Council of Hong Kong,China(Project Number:152093/18E).
文摘The photovoltaic performance of perovskite solar cells(PSCs)can be improved by utilizing efficient front contact.However,it has always been a significant challenge for fabricating high-quality,scalable,controllable,and cost-effective front contact.This study proposes a realistic multi-layer front contact design to realize efficient single-junction PSCs and perovskite/perovskite tandem solar cells(TSCs).As a critical part of the front contact,we prepared a highly compact titanium oxide(TiO2)film by industrially viable Spray Pyrolysis Deposition(SPD),which acts as a potential electron transport layer(ETL)for the fabrication of PSCs.Optimization and reproducibility of the TiO2 ETL were discreetly investigated while fabricating a set of planar PSCs.As the front contact has a significant influence on the optoelectronic properties of PSCs,hence,we investigated the optics and electrical effects of PSCs by three-dimensional(3D)finite-difference time-domain(FDTD)and finite element method(FEM)rigorous simulations.The investigation allows us to compare experimental results with the outcome from simulations.Furthermore,an optimized single-junction PSC is designed to enhance the energy conversion efficiency(ECE)by>30% compared to the planar reference PSC.Finally,the study has been progressed to the realization of all-perovskite TSC that can reach the ECE,exceeding 30%.Detailed guidance for the completion of high-performance PSCs is provided.
基金supported by the"Thousands Talents"program for pioneer researcher and his innovation team,Chinathe National Natural Science Foundation of China(51374029 and 91433102)+1 种基金the Program for New Century Excellent Talents in the University(NCET-13-0668)the Fundamental Research Funds for the Central Universities(FRF-TP-14-008C1)
文摘Perovskite solar cells are known to have a power conversion efficiency dependent on subtle variation in chemical composition and crystal and microstructures of materials,processing conditions,and device fabrication procedures and conditions.The present work demonstrates such strong dependence of power conversion efficiency on a TiO_2 film made of the same sol with various aging time.A dense and conformal TiO_2 film was prepared by sol-gel method,and the influences of its surface morphology and thickness on performance of perovskite solar cells have been investigated.The surface morphology and thickness of the TiO_2 film were tuned by adjusting the aging time of sol,resulting in enhanced short-circuit current density and fill factor of the perovskite solar cells due to increased coverage and roughness of perovskite films,light refraction,and effective charge recombination blocking effect,which were verified by means of the light absorption spectra,photoluminescence of perovskite films with and without hole transport layer,cyclic voltammogram,and electrochemical impedance spectra.The cells with a dense and conformal TiO_2 compact layer derived from the sol aged for 4 h exhibit a power conversion efficiency of 15.7%,50% higher than the efficiency based on TiO_2 layer derived from 0 h aging sol and 3 times of the efficiency with TiO_2 layer made from 8 h aged sol.
基金Project supported by the National Natural Science Foundation of China(Nos.51472071,51272061,51072043)the National Basic Research Program of China(No.2011CBA00700)
文摘A hydrolysis process was applied to prepare the compact TiO2 layer using the fresh metastable TIC14 isopropanol/water solution as the precursor solution for the preparation of the inorganic-organic hybrid heterojunction perovskite solar cells. The optimal compact TiO2 layer prepared from the aqueous solution of 2 mol/L TiCl4 diluted in isopropanol at 1 ： 3 by volume as precursor solution was uniform and with a film thickness of 126 nm. The corresponding perovskite solar cell gave a photovoltaic conversion efficiency of 10.61%.
基金Project supported by the National Natural Science Foundation of China(Nos.51472071,512720616,51072043)the National Basic Research Program of China(No.2011CBA00700)
文摘The tungsten trioxide（WO3） thin films were firstly prepared by spin-coating-pyrolysis methods using the ammonium metatungstate（（NH4）6H2W12O40）DMF/water solution, and successfully applied as the efficient compact layers for the planar perovskite solar cells. The influence of the WO3 film thickness and the rinsing treatment of CH_3NH_3 PbI_3 thin film with isopropanol on the photovoltaic performance of the corresponding perovskite solar cells was systematically investigated. The results revealed that the perovskite solar cell with a 62 nm thick WO3 compact layer achieved a photoelectric conversion efficiency of 5.72%, with a short circuit photocurrent density of 17.39 mA/cm^2, an open circuit voltage of 0.58 V and a fill factor of 0.57. The photoelectric conversion efficiency was improved from 5.72% to 7.04% by the isopropanol rinsing treatment.
