The photovoltaic performance of perovskite sloar cells(PSCs)is strongly dependent on the crystallinity,morphorlogy and defects of perovskite films.In the present work,a novel strategy was developed to fabricate the hi...The photovoltaic performance of perovskite sloar cells(PSCs)is strongly dependent on the crystallinity,morphorlogy and defects of perovskite films.In the present work,a novel strategy was developed to fabricate the high quality CsPbI3 inorganic perovskite by tuning the growth dynamics of CsPbI3 by pretreatment of fresh CsPbI3 films with phenylethylamine iodide(PEAI).The PEAI can mediate the phase transformation from 1D(DMAPbI3)(DMA:dimethylammonium)to 3D CsPbI3 all-inorganic perovskite films via the PEA2CsPb2I7 of 2D perovskite intermediate phase,resulting in highly crystalline CsPbI3 perovskite films with remarkably enlarged grains and reduced defects.The as-achieved highly crystalline CsPbI3 inorganic perovskite not only exhibited improved phase stability but also significant reduced defects.The perovskite solar cells based on these CsPbI3 thin films exhibited a champion efficiency of 17.08%,much higher than those prepared through posttreatment or direct addition of PEAI into CsPbI3 precursor solution.This work not only developed an effective strategy to prepare high crystalline CsPbI3 film and highly efficient CsPbI3-based all-inorganic PSCs,but also unraveled the mediation mechanism of CsPbI3by pre-treatment of PEAI,shedding light for further development of high perfomance perovskite-based optoelectronics.展开更多
Unlike organic–inorganic hybrid perovskites, all-inorganic cesium lead halide perovskites hold great promise for developing high-performance optoelectronic devices, owing to their improved stability. Herein, we inves...Unlike organic–inorganic hybrid perovskites, all-inorganic cesium lead halide perovskites hold great promise for developing high-performance optoelectronic devices, owing to their improved stability. Herein, we investigate the perovskite-related CsPb_2 Br_5 nanoplatelets(NPLs) with tunable emission wavelengths via changing the reaction temperatures to 100°C, 120°C, and 140°C. Reaction temperature plays a key role in determining the shapes and thicknesses of the resulting CsPb_2 Br_5 NPLs. A higher temperature is in favor of the formation of smaller and thicker NPLs. To develop their potential applications in optoelectronic devices, green light emitting diodes(LEDs) and photodetectors based on CsPb_2 Br_5 NPLs are fabricated. The green LEDs based on CsPb_2 Br_5 NPLs synthesized at 140°C exhibit an excellent pure green emission(full width at half-maximum of <20 nm) and display a luminous efficiency of 34.49 lm∕W under an operation current of 10 m A. Moreover, the photodetector based on CsPb_2 Br_5 NPLs synthesized at 100°C has better performance with a rise time of 0.426 s, a decay time of0.422 s, and a ratio of the current(with and without irradiation) of 364%.展开更多
A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples,due to their typically limited time-stability,and the understanding of the role of external factors...A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples,due to their typically limited time-stability,and the understanding of the role of external factors that can induce a crystal phase transformation(such as humidity,intense light flux,temperature,etc.).In this perspective,it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant monitoring.In this paper we propose Raman spectroscopy as the ideal technique to solve this problem.The vibrational analysis of CsPbI3 in the a-phase and 5-phase and of the Cs4PbI6 secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT framework.Finally,the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process.展开更多
There are many strategies to maintain the excellent photoluminescence(PL) characteristics of perovskite quantum dots(QDs). Here, we proposed a facile and effective method to prepare cyan CsPb(Cl/Br)3/SiO2 nanospheres ...There are many strategies to maintain the excellent photoluminescence(PL) characteristics of perovskite quantum dots(QDs). Here, we proposed a facile and effective method to prepare cyan CsPb(Cl/Br)3/SiO2 nanospheres at room temperature. Cubic CsPb(Cl/Br)3 was obtained by adding a LiCl-H2O solution and anion exchange reaction. With(3-aminopropyl)triethoxysilane as an auxiliary agent, a QDs/SiO2 composite was extracted from a sol-gel solution by precipitate-encapsulation method. The transmission electron microscopy images and Fourier transform infrared spectra indicated the QDs were indeed embedded in silica substances.Besides, humidity stability and thermal stability show the composite possesses a great application value.Finally, cyan QDs@SiO2 powder has a high PL quantum yield of up to 84%;the stable cyan fluorescent powder does have great potential to play a key role in commercial full spectrum display.展开更多
Herein,we have developed a method for the facile aqueous synthesis of ligand-free cesium lead halide perovskite nanoplatelets with pure CsPb_(2)Br_(5).The ligand-free CsPb_(2)Br_(5)nanoplatelets showed good environmen...Herein,we have developed a method for the facile aqueous synthesis of ligand-free cesium lead halide perovskite nanoplatelets with pure CsPb_(2)Br_(5).The ligand-free CsPb_(2)Br_(5)nanoplatelets showed good environmental stability with green and easy synthesis.In addition to their demonstrated good stability in aqueous solutions,and enhanced charge separation and charge transportability.展开更多
Heteroepitaxy of high-quality GaN-based heterostructures with tunable band alignment and optical pro-perties is of central importance for their applications in electronics and optoelectronics.Incommensurate material g...Heteroepitaxy of high-quality GaN-based heterostructures with tunable band alignment and optical pro-perties is of central importance for their applications in electronics and optoelectronics.Incommensurate material growth on the GaN substrate with an abrupt interface is still a challenge due to the formation of high-density interface defects and structural disordering induced by the lattice mismatch.Herein,we report the heteroepitaxial growth of high-quality uniform CsPb(Br_(x)Cl_(1−x))_(3)perovskite alloy nanoplatelets on the c-GaN substrate with fully tunable compositions(0≤x≤1)via space-confined chemical vapor deposition.The formation of large-mismatch CsPb(Br_(x)Cl_(1−x))_(3)/GaN heterostructures arises from relatively weak interfacial interactions(0.58-0.61 J m^(−2))that reduce the impact of the lattice mismatch on the growth.The CsPb(Br_(x)Cl_(1−x))_(3)/GaN heterostructures exhibit type-Ⅱ band alignment with a tunable valence band offset from 0.85 to 1.34 eV and a conduction band offset from 0.45 to 0.61 eV,respectively.These heterostructures show remarkable photoluminescence quenching and reduced exciton lifetimes as com-pared with the CsPb(Br_(x)Cl_(1−x))_(3)nanoplatelets grown on mica,which are attributed to the enhanced carrier separation and extraction efficiencies.These findings of this work provide an efficient strategy for the advancement of the versatile synthesis of large-mismatch perovskite/GaN heterostructures and exhibit their excellent potential for various functional optoelectronics.展开更多
基金supported by the National Natural Science Foundation of China(No.51602106)。
文摘The photovoltaic performance of perovskite sloar cells(PSCs)is strongly dependent on the crystallinity,morphorlogy and defects of perovskite films.In the present work,a novel strategy was developed to fabricate the high quality CsPbI3 inorganic perovskite by tuning the growth dynamics of CsPbI3 by pretreatment of fresh CsPbI3 films with phenylethylamine iodide(PEAI).The PEAI can mediate the phase transformation from 1D(DMAPbI3)(DMA:dimethylammonium)to 3D CsPbI3 all-inorganic perovskite films via the PEA2CsPb2I7 of 2D perovskite intermediate phase,resulting in highly crystalline CsPbI3 perovskite films with remarkably enlarged grains and reduced defects.The as-achieved highly crystalline CsPbI3 inorganic perovskite not only exhibited improved phase stability but also significant reduced defects.The perovskite solar cells based on these CsPbI3 thin films exhibited a champion efficiency of 17.08%,much higher than those prepared through posttreatment or direct addition of PEAI into CsPbI3 precursor solution.This work not only developed an effective strategy to prepare high crystalline CsPbI3 film and highly efficient CsPbI3-based all-inorganic PSCs,but also unraveled the mediation mechanism of CsPbI3by pre-treatment of PEAI,shedding light for further development of high perfomance perovskite-based optoelectronics.
基金National Natural Science Foundation of China(NSFC)(61404017)Natural Science Foundation of Chongqing(cstc2017jcyj B0273)Chongqing Postdoctoral Science Research Special Funded Project(Xm2016017)
文摘Unlike organic–inorganic hybrid perovskites, all-inorganic cesium lead halide perovskites hold great promise for developing high-performance optoelectronic devices, owing to their improved stability. Herein, we investigate the perovskite-related CsPb_2 Br_5 nanoplatelets(NPLs) with tunable emission wavelengths via changing the reaction temperatures to 100°C, 120°C, and 140°C. Reaction temperature plays a key role in determining the shapes and thicknesses of the resulting CsPb_2 Br_5 NPLs. A higher temperature is in favor of the formation of smaller and thicker NPLs. To develop their potential applications in optoelectronic devices, green light emitting diodes(LEDs) and photodetectors based on CsPb_2 Br_5 NPLs are fabricated. The green LEDs based on CsPb_2 Br_5 NPLs synthesized at 140°C exhibit an excellent pure green emission(full width at half-maximum of <20 nm) and display a luminous efficiency of 34.49 lm∕W under an operation current of 10 m A. Moreover, the photodetector based on CsPb_2 Br_5 NPLs synthesized at 100°C has better performance with a rise time of 0.426 s, a decay time of0.422 s, and a ratio of the current(with and without irradiation) of 364%.
基金support of the"Fondazione di Sardegna"within the project L.R 7.CUP F74I19000930007"NG-Light:a new generation of phosphors".Technical support provided by A.Larranaga in SGIker(UPV/EHU,GV/EJ,ESF)is gratefully acknowledged.
文摘A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples,due to their typically limited time-stability,and the understanding of the role of external factors that can induce a crystal phase transformation(such as humidity,intense light flux,temperature,etc.).In this perspective,it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant monitoring.In this paper we propose Raman spectroscopy as the ideal technique to solve this problem.The vibrational analysis of CsPbI3 in the a-phase and 5-phase and of the Cs4PbI6 secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT framework.Finally,the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process.
基金supported by the Science and Technology Planning Project of Zhejiang Province(No.2018C01046)Enterprise-Funded Latitudinal Research Projects of China(Nos.J2016-141,J2017-171,J2017-293,and J2017-243)+1 种基金Shanghai Sailing Program(No.18YF1422500)Research Start-Up Project of Shanghai Institute of Technology(No.YJ2018-9)
文摘There are many strategies to maintain the excellent photoluminescence(PL) characteristics of perovskite quantum dots(QDs). Here, we proposed a facile and effective method to prepare cyan CsPb(Cl/Br)3/SiO2 nanospheres at room temperature. Cubic CsPb(Cl/Br)3 was obtained by adding a LiCl-H2O solution and anion exchange reaction. With(3-aminopropyl)triethoxysilane as an auxiliary agent, a QDs/SiO2 composite was extracted from a sol-gel solution by precipitate-encapsulation method. The transmission electron microscopy images and Fourier transform infrared spectra indicated the QDs were indeed embedded in silica substances.Besides, humidity stability and thermal stability show the composite possesses a great application value.Finally, cyan QDs@SiO2 powder has a high PL quantum yield of up to 84%;the stable cyan fluorescent powder does have great potential to play a key role in commercial full spectrum display.
基金supported by the National Natural Science Foundation of China(21874020)the Key Project of Natural Science Foundation of Fujian Province(2020J02038)+2 种基金the National Science Foundation for Distinguished Young Scholars of Fujian Province(2020J06019)Program for Fujian Youth Talent Support Project(2019B016)Program for Fujian Top-Notch Innovative Personnel(Fujian Commission Talent[2018]No.5).
文摘Herein,we have developed a method for the facile aqueous synthesis of ligand-free cesium lead halide perovskite nanoplatelets with pure CsPb_(2)Br_(5).The ligand-free CsPb_(2)Br_(5)nanoplatelets showed good environmental stability with green and easy synthesis.In addition to their demonstrated good stability in aqueous solutions,and enhanced charge separation and charge transportability.
基金supported in part by the Natural Science Foundation of Zhejiang Province(Grant No.LZ22F040003 and LY22A040002)the National Natural Science Foundation of China(Grant No.62174151 and 61775201)computational resources from the Shanghai Supercomputer Center are acknowledged.
文摘Heteroepitaxy of high-quality GaN-based heterostructures with tunable band alignment and optical pro-perties is of central importance for their applications in electronics and optoelectronics.Incommensurate material growth on the GaN substrate with an abrupt interface is still a challenge due to the formation of high-density interface defects and structural disordering induced by the lattice mismatch.Herein,we report the heteroepitaxial growth of high-quality uniform CsPb(Br_(x)Cl_(1−x))_(3)perovskite alloy nanoplatelets on the c-GaN substrate with fully tunable compositions(0≤x≤1)via space-confined chemical vapor deposition.The formation of large-mismatch CsPb(Br_(x)Cl_(1−x))_(3)/GaN heterostructures arises from relatively weak interfacial interactions(0.58-0.61 J m^(−2))that reduce the impact of the lattice mismatch on the growth.The CsPb(Br_(x)Cl_(1−x))_(3)/GaN heterostructures exhibit type-Ⅱ band alignment with a tunable valence band offset from 0.85 to 1.34 eV and a conduction band offset from 0.45 to 0.61 eV,respectively.These heterostructures show remarkable photoluminescence quenching and reduced exciton lifetimes as com-pared with the CsPb(Br_(x)Cl_(1−x))_(3)nanoplatelets grown on mica,which are attributed to the enhanced carrier separation and extraction efficiencies.These findings of this work provide an efficient strategy for the advancement of the versatile synthesis of large-mismatch perovskite/GaN heterostructures and exhibit their excellent potential for various functional optoelectronics.
