Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm ...Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide(MAPbI_(3)) ultrathin films via co-deposition of PbI_2 and CH_3NH_3I(MAI) on chemical-vapor-deposition-grown monolayer MoS_(2) as well as the corresponding photoluminescence(PL) properties at different growing stages. Atomic force microscopy and scanning electron microscopy measurements reveal the MoS_(2) tuned growth of MAPbI_(3) in a Stranski–Krastanov mode. PL and Kelvin probe force microscopy results confirm that MAPbI_(3) /MoS_(2) heterostructures have a type-Ⅱ energy level alignment at the interface. Temperaturedependent PL measurements on layered MAPbI_(3) (at the initial stage) and on MAPbI_(3) crystals in averaged size of 500 nm(at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI_(3) /transition-metal dichalcogenide based innovative devices for wider optoelectronic applications.展开更多
The interface defects and nickel vacancies of the NiO_(x)lead to interface charge recombination,which limits its application in perovskite solar cells.Here,graphdiyne oxide(GDYO)was added to NiO_(x)as an inorganic hol...The interface defects and nickel vacancies of the NiO_(x)lead to interface charge recombination,which limits its application in perovskite solar cells.Here,graphdiyne oxide(GDYO)was added to NiO_(x)as an inorganic hole transporting material.It is found that the average carrier lifetime declined from 29.2 ns to 5.4 ns and the recombination resistance increased significantly after the GDYO adding determined by the time-resolved photoluminescence and electrochemical impedance spectroscopy analysis.We further demonstrated that the GDYO adding to NiO_(x)effectively improved the charge extraction,accelerated the charge transportation and suppressed the charge recombination.Consequently,the optimized NiO_(x)(GDYO)-based cell showed superior performance with a higher fill factor(81.99%)and improved stability with respect to the reference device.This method provides a new method for property regulation of NiO_(x)in inverted planar MAPbI_(3) perovskite solar cells.展开更多
Organic-inorganic metal halide perovskite solar cells have achieved high efficiency of 25.5%.Finding an effective means to suppress the formation of traps and correlate stability losses are thought to be a promising r...Organic-inorganic metal halide perovskite solar cells have achieved high efficiency of 25.5%.Finding an effective means to suppress the formation of traps and correlate stability losses are thought to be a promising route for further increasing the photovoltaic performance and commercialization potential of perovskite photovoltaic devices.Herein,we report a facile passivation model,which uses a multi-functional organic molecule to simultaneously realize the chemical passivation and field-effect passivation for the perovskite film by an upgraded anti-solvent coating method,which reduces the trap states density of the perovskite,improves interface charge transfer,and thus promotes device performance.In addition,the hydrophobic groups of the molecules can form a moisture-repelling barrier on the perovskite grains,which apparently promotes the humidity stability of the solar cells.Therefore,the optimal power conversion efficiency(PCE)of perovskite solar cells after synergistic passivation reaches 21.52%,and it can still retain 95%of the original PCE when stored in-40%humidity for 30 days.Our findings extend the scope for traps passivation to further promote both the photovoltaic performance and the stability of the perovskite solar cells.展开更多
Metal halide perovskites(MHPs) are gaining increasing attention as low-cost, high-performance semiconductors for optoelectronics. In particular, their solution processing is compatible with the largescale manufacturin...Metal halide perovskites(MHPs) are gaining increasing attention as low-cost, high-performance semiconductors for optoelectronics. In particular, their solution processing is compatible with the largescale manufacturing of thin-film devices, including solar cells and light-emitting diodes.Understanding the coordination chemistry in precursor-solvent solution and atomistic mechanisms of film formation is of great importance for optimizing the optoelectronic properties of the final films.Using the methylammonium lead triiodide(MAPbI_(3)) as an example, we study the complex evolution of the molecular species from the solution to the initial stage of the crystallization by using a combination of density functional theory(DFT) calculations and ab-initio molecular dynamics(AIMD) simulations. We focus on the widely employed solvents DMSO and DMF, analyze the structures and energies of the iodoplumbate complexes in the form of simple complex of [PbI_(m)L_(n)]^(2-m))_(x) and polymeric iodoplumbates of([PbI_(m)L_(n)]^(2-m))_(x). Based on the calculated formation enthalpies, we propose reaction schemes of MAPbI_(3) formation in DMSO, DMF and DMF-DMSO binary solvent and explain the advantages of the binary solvent.We highlight the important role of NH...O hydrogen bonds in the formation of iodoplumbates monomers.Our calculations indicate unbalanced reaction energies at several elementary reaction steps in either DMF(formation of [PbI_(4)L_(n)]^(2-) being highly favourable) or DMSO(formation of [PbI_(5)L_(n)]^(3- )being retarded).Mixing a small amount of DMSO in DMF gives rise to a better balance in the energies and, therefore,potentially better equilibria in the overall crystallization process and better quality of the final perovskite films.展开更多
Ferroelectric polymers,such as poly(vinylidene fluoride-trifluoroethylene)[P(VDF-TrFE)or PVTF]have attracted growing interest in developing flexible devices because of their excellent ferroelectricity and piezoelectri...Ferroelectric polymers,such as poly(vinylidene fluoride-trifluoroethylene)[P(VDF-TrFE)or PVTF]have attracted growing interest in developing flexible devices because of their excellent ferroelectricity and piezoelectricity.High coercive field(E c)inherent to PVTF for switching its polarization,however,is not beneficial for practical memory or sensor device application.Different strategies,including irradiation and interface control,have been thus developed to reduce E c.Despite many efforts,a facile approach to tailoring intrinsic E_(c) of PVTF has not been documented.In this work,an optically controlled E_(c) was reported,which is achieved for the first time by introducing photosensitive MAPbI3 nanocrystals into PVTF matrix.When exposed to the irradiation of 532 nm laser light,a decreased E_(c) of the composites can be achieved reversibly by increasing the light density.The decreased level of E_(c) increases as the MAPbI3 content enhanced,and a 10.7%reduction of E_(c) can be achieved in 15%(mass fraction)MAPbI3/PVTF samples.These results could be attributed to loading an internal stress on PVTF,which was generated by the photostriction of MAPbI3 nanocrystals.This explanation was further supported by in-situ XRD results under irradiation of 532 nm laser light.Our findings may offer the opportunity to optically modulate the ferroelectric properties of PVTF composites for optimized device performances.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11874427 and 11804395)the Fundamental Research Funds for the Central Universities of Central South University (Grant No.2020zzts377)。
文摘Hybrid organic–inorganic perovskite thin films have attracted much attention in optoelectronic and information fields because of their intriguing properties. Due to quantum confinement effects, ultrathin films in nm scale usually show special properties. Here, we report on the growth of methylammonium lead iodide(MAPbI_(3)) ultrathin films via co-deposition of PbI_2 and CH_3NH_3I(MAI) on chemical-vapor-deposition-grown monolayer MoS_(2) as well as the corresponding photoluminescence(PL) properties at different growing stages. Atomic force microscopy and scanning electron microscopy measurements reveal the MoS_(2) tuned growth of MAPbI_(3) in a Stranski–Krastanov mode. PL and Kelvin probe force microscopy results confirm that MAPbI_(3) /MoS_(2) heterostructures have a type-Ⅱ energy level alignment at the interface. Temperaturedependent PL measurements on layered MAPbI_(3) (at the initial stage) and on MAPbI_(3) crystals in averaged size of 500 nm(at the later stage) show rather different temperature dependence as well as the phase transitions from tetragonal to orthorhombic at 120 and 150 K, respectively. Our findings are useful in fabricating MAPbI_(3) /transition-metal dichalcogenide based innovative devices for wider optoelectronic applications.
基金This work was supported by the National Natural Science Foundation of China(No.21975273)the Scientific Research Starting Foundation of Outstanding Young Scholar of Shandong University,Chinathe Fundamental Research Funds of Shandong University,China.
文摘The interface defects and nickel vacancies of the NiO_(x)lead to interface charge recombination,which limits its application in perovskite solar cells.Here,graphdiyne oxide(GDYO)was added to NiO_(x)as an inorganic hole transporting material.It is found that the average carrier lifetime declined from 29.2 ns to 5.4 ns and the recombination resistance increased significantly after the GDYO adding determined by the time-resolved photoluminescence and electrochemical impedance spectroscopy analysis.We further demonstrated that the GDYO adding to NiO_(x)effectively improved the charge extraction,accelerated the charge transportation and suppressed the charge recombination.Consequently,the optimized NiO_(x)(GDYO)-based cell showed superior performance with a higher fill factor(81.99%)and improved stability with respect to the reference device.This method provides a new method for property regulation of NiO_(x)in inverted planar MAPbI_(3) perovskite solar cells.
基金support from the National Natural Science Foundation of China(Nos.61775081,11904127,22075101,61904066,61705020)Program for the Development of Science and Technology of Jilin Province(Nos.20200801032GH and 20190103002JH)+2 种基金the Thirteenth Five-Year Program for Science and Technology of Education Department of Jilin Province(Nos.JJKH20200417KJ)Special Project of Industrial Technology Research and Development in Jilin Province(No.2019C042-2)Construction Program for Innovation Research Team of Jilin Normal University(No.201703).
文摘Organic-inorganic metal halide perovskite solar cells have achieved high efficiency of 25.5%.Finding an effective means to suppress the formation of traps and correlate stability losses are thought to be a promising route for further increasing the photovoltaic performance and commercialization potential of perovskite photovoltaic devices.Herein,we report a facile passivation model,which uses a multi-functional organic molecule to simultaneously realize the chemical passivation and field-effect passivation for the perovskite film by an upgraded anti-solvent coating method,which reduces the trap states density of the perovskite,improves interface charge transfer,and thus promotes device performance.In addition,the hydrophobic groups of the molecules can form a moisture-repelling barrier on the perovskite grains,which apparently promotes the humidity stability of the solar cells.Therefore,the optimal power conversion efficiency(PCE)of perovskite solar cells after synergistic passivation reaches 21.52%,and it can still retain 95%of the original PCE when stored in-40%humidity for 30 days.Our findings extend the scope for traps passivation to further promote both the photovoltaic performance and the stability of the perovskite solar cells.
基金funding by the Computational Sciences for Energy Research (CSER) tenure track program of Shell and NWO (Project No. 15CST04-2)funding by the Computational Sciences for Energy Research (CSER) tenure track program of Shell and NWO(Project No. 15CST04-2)+1 种基金funding support from the NWO START-UP from the Netherlandsthe NWO START-UP from the Netherlands。
文摘Metal halide perovskites(MHPs) are gaining increasing attention as low-cost, high-performance semiconductors for optoelectronics. In particular, their solution processing is compatible with the largescale manufacturing of thin-film devices, including solar cells and light-emitting diodes.Understanding the coordination chemistry in precursor-solvent solution and atomistic mechanisms of film formation is of great importance for optimizing the optoelectronic properties of the final films.Using the methylammonium lead triiodide(MAPbI_(3)) as an example, we study the complex evolution of the molecular species from the solution to the initial stage of the crystallization by using a combination of density functional theory(DFT) calculations and ab-initio molecular dynamics(AIMD) simulations. We focus on the widely employed solvents DMSO and DMF, analyze the structures and energies of the iodoplumbate complexes in the form of simple complex of [PbI_(m)L_(n)]^(2-m))_(x) and polymeric iodoplumbates of([PbI_(m)L_(n)]^(2-m))_(x). Based on the calculated formation enthalpies, we propose reaction schemes of MAPbI_(3) formation in DMSO, DMF and DMF-DMSO binary solvent and explain the advantages of the binary solvent.We highlight the important role of NH...O hydrogen bonds in the formation of iodoplumbates monomers.Our calculations indicate unbalanced reaction energies at several elementary reaction steps in either DMF(formation of [PbI_(4)L_(n)]^(2-) being highly favourable) or DMSO(formation of [PbI_(5)L_(n)]^(3- )being retarded).Mixing a small amount of DMSO in DMF gives rise to a better balance in the energies and, therefore,potentially better equilibria in the overall crystallization process and better quality of the final perovskite films.
基金Natural Science Foundation of Zhejiang Province,China(No.LR21E020004)National Natural Science Foundation of China(No.U1909212)Project of the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,China(No.2021SX-FR007).
文摘Ferroelectric polymers,such as poly(vinylidene fluoride-trifluoroethylene)[P(VDF-TrFE)or PVTF]have attracted growing interest in developing flexible devices because of their excellent ferroelectricity and piezoelectricity.High coercive field(E c)inherent to PVTF for switching its polarization,however,is not beneficial for practical memory or sensor device application.Different strategies,including irradiation and interface control,have been thus developed to reduce E c.Despite many efforts,a facile approach to tailoring intrinsic E_(c) of PVTF has not been documented.In this work,an optically controlled E_(c) was reported,which is achieved for the first time by introducing photosensitive MAPbI3 nanocrystals into PVTF matrix.When exposed to the irradiation of 532 nm laser light,a decreased E_(c) of the composites can be achieved reversibly by increasing the light density.The decreased level of E_(c) increases as the MAPbI3 content enhanced,and a 10.7%reduction of E_(c) can be achieved in 15%(mass fraction)MAPbI3/PVTF samples.These results could be attributed to loading an internal stress on PVTF,which was generated by the photostriction of MAPbI3 nanocrystals.This explanation was further supported by in-situ XRD results under irradiation of 532 nm laser light.Our findings may offer the opportunity to optically modulate the ferroelectric properties of PVTF composites for optimized device performances.
