Two-dimensional(2D) PbI_2 flakes have been attracting intensive attention as one potential candidate for the modern optoelectronics. However, suffered from the instability of kinetics-driven growth, the fabricated 2D ...Two-dimensional(2D) PbI_2 flakes have been attracting intensive attention as one potential candidate for the modern optoelectronics. However, suffered from the instability of kinetics-driven growth, the fabricated 2D PbI_2 flakes have a wide dimensional distribution even under the same conditions. Herein, a novel facile space confined physical vapor deposition(PVD) process is provided to synthesize uniform triangle PbI_2 flakes with high quality. The confined space provides a relatively stable growth environment that renders more control on the growth kinetics, leading to highly uniform triangle PbI_2 flakes with the average size of 5 mm and thickness of 17 nm. Moreover, as-fabricated PbI_2-based photodetectors show promising stable and flexible optoelectronic performances to 470 nm light, including high responsivity(0.72 AW^(-1)), large on/off ratio up to 900, fast photoresponse speed(rise time of 13.5 ms and decay time of 20 ms) and high detectivity(1.04×10^(10) Jones). The well-controllable growth of the uniform triangle PbI_2 flakes and the detailed exploration of their optoelectronic properties are particularly valuable for their further practical applications.展开更多
Organic-inorganic halide perovskite (ABX3) solar cells (PSCs)have made great progress in recent years [1]. The power conversion efficiency (PCE) has increased up to 25.2%(NREL Best Research-Cell Efficiency Chart, http...Organic-inorganic halide perovskite (ABX3) solar cells (PSCs)have made great progress in recent years [1]. The power conversion efficiency (PCE) has increased up to 25.2%(NREL Best Research-Cell Efficiency Chart, https://www.nrel.gov/pv/cell-efficiency.html, Accessed August 2019). However, they suffer from poor thermal stability due to the volatile A-site organic cations.展开更多
Controlling the morphology of the perovskite film is an effective way to improve the photoelectric conversion efficiency of solar cell devices. In this work, we study the influence of the crystallization condition on ...Controlling the morphology of the perovskite film is an effective way to improve the photoelectric conversion efficiency of solar cell devices. In this work, we study the influence of the crystallization condition on PbI2 morphology and the performances of resulting perovskite solar cells. The PbI2 morphologies and coverage rates under different formation conditions such as solvent effect, slow crystallization at room temperature and substrate-preheating, are found to be of crucial importance for preparing high-quality perovskite. The generation of loosely packed disk-like PbI2 film with interpenetrating nanopores promotes the penetration of methyl ammonium iodide （MAI）, leading to a better crystallinity of the perovskite film, and a best repeatable power conversion efficiency of 11.59% is achieved when methyl ammonium lead triiodide （CH3NH3PbI3, MAPbI3） is employed. In addition, an excellent device is also obtained with an efficiency of more than 93% to remain after working for 43 days.展开更多
X-ray detection is widely used in research[1−3],product in-spection[4],nuclear station,and medical imaging.Si[5],α-Se[6],PbI2[7],and CdZnTe[8]are conventional semiconductors,and some problems limit their applications...X-ray detection is widely used in research[1−3],product in-spection[4],nuclear station,and medical imaging.Si[5],α-Se[6],PbI2[7],and CdZnTe[8]are conventional semiconductors,and some problems limit their applications.For instance,Si andα-Se have low stopping power for X-ray[8],which hinders their application in high-energy range over 50 keV.Moreover,the complicated preparation,high operating voltage,and high fab-rication cost of these materials are the negative issues.展开更多
The stimulated emission at 722.9nm is observed by a direct photodissociation of the PbI2 molecules with a 266nm pulse laser.The possible dissociation channels are discussed.Two-photon resonant photodissociation mechan...The stimulated emission at 722.9nm is observed by a direct photodissociation of the PbI2 molecules with a 266nm pulse laser.The possible dissociation channels are discussed.Two-photon resonant photodissociation mechanism is used to explain the generation of the 722.9 nm emission.The emission is measured at different incident laser energy and heat-pipe temperature.The obtained experimental result is well supported by the photodissociation mechanism given by us.展开更多
Organic-inorganic hybrid two-dimensional(2D)ruddlesden-popper(RP)perovskites with fantastic optoelectronic properties and good stability have attracted tremendous attention for the potential applications in photovolta...Organic-inorganic hybrid two-dimensional(2D)ruddlesden-popper(RP)perovskites with fantastic optoelectronic properties and good stability have attracted tremendous attention for the potential applications in photovoltaics and electroluminescence.Recently,a new allinorganic Cs2PbI2Cl22D perovskite has been proposed with excellent excitonic absorption and improved ambient and thermal stability.Herein,an interesting light-induced phase transition and photochromism in the Cs2PbI2Cl2were reported.Under low fluence light pumping,the room temperature photoluminescence(PL)of Cs2PbI2Cl2is dominated by a weak violet excitonic emission peaked at 412 nm.Surprisingly,the emission color gradually changes from violet to bright red while increasing the laser pumping fluence.This photochromic effect is determined to be caused by forming CsPbI3phase within the Cs2PbI2Cl2crystals,which is efficiently driven by thermal energy.Due to protection by the Cs2PbI2Cl2matrix,the embedded CsPbI3nanocrystals show improved stability than standard pure CsPbI3.Therefore,the Cs2PbI2Cl2perovskite with photochromic feature may find applications in optical encryption,as preliminarily shown in this work.展开更多
基金supported by the National Natural Science Foundation of China (51472097, 91622117, 21501060, and 51727809)the National Key Research and Development Program (2016YFB0401100)+1 种基金the National Basic Research Program of China (2015CB932600)the Fundamental Research Funds for the Central University (2017KFKJXX007, 2015ZDTD038)
文摘Two-dimensional(2D) PbI_2 flakes have been attracting intensive attention as one potential candidate for the modern optoelectronics. However, suffered from the instability of kinetics-driven growth, the fabricated 2D PbI_2 flakes have a wide dimensional distribution even under the same conditions. Herein, a novel facile space confined physical vapor deposition(PVD) process is provided to synthesize uniform triangle PbI_2 flakes with high quality. The confined space provides a relatively stable growth environment that renders more control on the growth kinetics, leading to highly uniform triangle PbI_2 flakes with the average size of 5 mm and thickness of 17 nm. Moreover, as-fabricated PbI_2-based photodetectors show promising stable and flexible optoelectronic performances to 470 nm light, including high responsivity(0.72 AW^(-1)), large on/off ratio up to 900, fast photoresponse speed(rise time of 13.5 ms and decay time of 20 ms) and high detectivity(1.04×10^(10) Jones). The well-controllable growth of the uniform triangle PbI_2 flakes and the detailed exploration of their optoelectronic properties are particularly valuable for their further practical applications.
基金the National Key Research and Development Program of China (2017YFA0206600)the National Natural Science Foundation of China (51773045, 21572041 and 21772030) for financial support
文摘Organic-inorganic halide perovskite (ABX3) solar cells (PSCs)have made great progress in recent years [1]. The power conversion efficiency (PCE) has increased up to 25.2%(NREL Best Research-Cell Efficiency Chart, https://www.nrel.gov/pv/cell-efficiency.html, Accessed August 2019). However, they suffer from poor thermal stability due to the volatile A-site organic cations.
基金Project supported by the National Natural Science Foundation of China(Grant No.61404007)the Beijing Talents Fund,China(Grant No.2015000021223ZK38)
文摘Controlling the morphology of the perovskite film is an effective way to improve the photoelectric conversion efficiency of solar cell devices. In this work, we study the influence of the crystallization condition on PbI2 morphology and the performances of resulting perovskite solar cells. The PbI2 morphologies and coverage rates under different formation conditions such as solvent effect, slow crystallization at room temperature and substrate-preheating, are found to be of crucial importance for preparing high-quality perovskite. The generation of loosely packed disk-like PbI2 film with interpenetrating nanopores promotes the penetration of methyl ammonium iodide （MAI）, leading to a better crystallinity of the perovskite film, and a best repeatable power conversion efficiency of 11.59% is achieved when methyl ammonium lead triiodide （CH3NH3PbI3, MAPbI3） is employed. In addition, an excellent device is also obtained with an efficiency of more than 93% to remain after working for 43 days.
基金the National Natural Science Foundation of China (62104194) for financial supportthe National Key Research and Development Program of China (2017YFA0206600)+1 种基金the National Natural Science Foundation of China (51922032 and 21961160720)the open research fund of Songshan Lake Materials Laboratory (2021SLABF K02) for financial support。
文摘X-ray detection is widely used in research[1−3],product in-spection[4],nuclear station,and medical imaging.Si[5],α-Se[6],PbI2[7],and CdZnTe[8]are conventional semiconductors,and some problems limit their applications.For instance,Si andα-Se have low stopping power for X-ray[8],which hinders their application in high-energy range over 50 keV.Moreover,the complicated preparation,high operating voltage,and high fab-rication cost of these materials are the negative issues.
基金Supported by the National Natural Science Foundation of China for Distinguished Young Scholars(19825110)National High Technology 410 Project.
文摘The stimulated emission at 722.9nm is observed by a direct photodissociation of the PbI2 molecules with a 266nm pulse laser.The possible dissociation channels are discussed.Two-photon resonant photodissociation mechanism is used to explain the generation of the 722.9 nm emission.The emission is measured at different incident laser energy and heat-pipe temperature.The obtained experimental result is well supported by the photodissociation mechanism given by us.
基金supported by the Open Fund of the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University,PLN2021-17)the Science and Technology Project of Southwest Petroleum University(2021JBGS08)Sichuan Science and Technology Program(2022YFSY0040)。
基金supported by the Macao Science and Technology Development Fund(FDCT-116/2016/A3,FDCT-091/2017/A2,FDCT-014/2017/AMJ and FDCT-199/2017/A3)Start-up Research Grant Fund from University of Macao(SRG2016-00002-FST)+3 种基金Research and Development Grant for Chair Professor Fund from University of Macao(CPG2018-00026-FST)Research Grant(SRG201600087-FST,MYRG2018-00148-IAPME and MYRG2018-00142-IAPME)from University of Macaothe National Natural Science Foundation of China(91733302,61935017 and 61605073)the Natural Science Foundation of Guangdong Province of China(2019A1515012186)。
文摘Organic-inorganic hybrid two-dimensional(2D)ruddlesden-popper(RP)perovskites with fantastic optoelectronic properties and good stability have attracted tremendous attention for the potential applications in photovoltaics and electroluminescence.Recently,a new allinorganic Cs2PbI2Cl22D perovskite has been proposed with excellent excitonic absorption and improved ambient and thermal stability.Herein,an interesting light-induced phase transition and photochromism in the Cs2PbI2Cl2were reported.Under low fluence light pumping,the room temperature photoluminescence(PL)of Cs2PbI2Cl2is dominated by a weak violet excitonic emission peaked at 412 nm.Surprisingly,the emission color gradually changes from violet to bright red while increasing the laser pumping fluence.This photochromic effect is determined to be caused by forming CsPbI3phase within the Cs2PbI2Cl2crystals,which is efficiently driven by thermal energy.Due to protection by the Cs2PbI2Cl2matrix,the embedded CsPbI3nanocrystals show improved stability than standard pure CsPbI3.Therefore,the Cs2PbI2Cl2perovskite with photochromic feature may find applications in optical encryption,as preliminarily shown in this work.
