The morphology and interface of perovskite film are very important for the performance of perovskite solar cells(PSCs).The quality of perovskite film,fabricated via two-step spin-coating process,is significantly influ...The morphology and interface of perovskite film are very important for the performance of perovskite solar cells(PSCs).The quality of perovskite film,fabricated via two-step spin-coating process,is significantly influenced by the morphology and crystallinity of PbI2 film.With the addition of additive dimethyl sulfoxide(DMSO)into the PbI2 precursor,the roughness and trap-state density of perovskite film have been significantly reduced,leading to the excellent contact between perovskite layer and subsequent deposited carrier transport layer.Accordingly,the planar heterojunction PSCs with an architecture of ITO/SnO2/perovskite/PTAA/Ag show an efficiency up to 19.02%.Furthermore,PSCs exhibit promising stability in air with a humidity of ~45%,and retain 80% of initial efficiency after being exposed to air for 400 h without any encapsulation.展开更多
This work reports the cost-effective growth of Mg:PbI2 nanostructures with 0,1,2.5 and 5.0 wt.%Mg doping concentrations.Structural,vibrational,morphological properties are analyzed using x-ray diffraction(XRD),Raman s...This work reports the cost-effective growth of Mg:PbI2 nanostructures with 0,1,2.5 and 5.0 wt.%Mg doping concentrations.Structural,vibrational,morphological properties are analyzed using x-ray diffraction(XRD),Raman spectroscopy and scanning electron microscopy(SEM).XRD and Raman studies confirm the monophasic hexagonal system of Mg:PbI2,and no additional impurity peaks are detected.The Scherrer formula is used to determine sizes of crystallites to be in the range of 47-52 nm.EDX/SEM e-mapping analyses confirm the incorporation of Mg in PbI2 matrix and its uniform distribution throughout the sample.The hexagonal nanosheet-and nanoplate-like morphologies are detected in SEM images for pure and Mg-doped PbI2.An optical band gap of nanostructures is obtained from Tauc’s relation to be in the range 3.0-3.25 eV.Dielectric and electrical properties are found in significant enhancement as Mg doping in PbI2 matrix,also the conduction mechanism is discussed.展开更多
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
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
PbI2/MoS2,as a typical van der Waals(vdW)heterostructure,has attracted intensive attention owing to its remarkable electronic and optoelectronic properties.In this work,the effect of defects on the electronic structur...PbI2/MoS2,as a typical van der Waals(vdW)heterostructure,has attracted intensive attention owing to its remarkable electronic and optoelectronic properties.In this work,the effect of defects on the electronic structures of a PbI2/MoS2 heterointerface has been systematically investigated.The manner in which the defects modulate the band structure of PbI2/MoS2,including the band gap,band edge,band alignment,and defect energy-level density within the band gap is discussed herein.It is shown that sulfur defects tune the band gaps,iodine defects shift the positions of the band edge and Fermi level,and lead defects realize the conversions between the straddling-gap band alignment and valence-band-aligned gap,thus enhancing the light-absorption ability of the material.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51673214)the National Key Research and Development Program of China(Grant No.2017YFA0206600)。
文摘The morphology and interface of perovskite film are very important for the performance of perovskite solar cells(PSCs).The quality of perovskite film,fabricated via two-step spin-coating process,is significantly influenced by the morphology and crystallinity of PbI2 film.With the addition of additive dimethyl sulfoxide(DMSO)into the PbI2 precursor,the roughness and trap-state density of perovskite film have been significantly reduced,leading to the excellent contact between perovskite layer and subsequent deposited carrier transport layer.Accordingly,the planar heterojunction PSCs with an architecture of ITO/SnO2/perovskite/PTAA/Ag show an efficiency up to 19.02%.Furthermore,PSCs exhibit promising stability in air with a humidity of ~45%,and retain 80% of initial efficiency after being exposed to air for 400 h without any encapsulation.
基金Project supported by the Deanship of Scientific Research at King Khalid University(Grant No.R.G.P1/207/41)the Deanship of Scientific Research at Princess Nourah bint Abdulrahman University through the Fast-track Research Funding Program,and Deanship of Research,University of Hail.
文摘This work reports the cost-effective growth of Mg:PbI2 nanostructures with 0,1,2.5 and 5.0 wt.%Mg doping concentrations.Structural,vibrational,morphological properties are analyzed using x-ray diffraction(XRD),Raman spectroscopy and scanning electron microscopy(SEM).XRD and Raman studies confirm the monophasic hexagonal system of Mg:PbI2,and no additional impurity peaks are detected.The Scherrer formula is used to determine sizes of crystallites to be in the range of 47-52 nm.EDX/SEM e-mapping analyses confirm the incorporation of Mg in PbI2 matrix and its uniform distribution throughout the sample.The hexagonal nanosheet-and nanoplate-like morphologies are detected in SEM images for pure and Mg-doped PbI2.An optical band gap of nanostructures is obtained from Tauc’s relation to be in the range 3.0-3.25 eV.Dielectric and electrical properties are found in significant enhancement as Mg doping in PbI2 matrix,also the conduction mechanism is discussed.
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.
基金National Natural Science Foundation of China(Grant No.11672079)the National Science Foundation of Beijing(Grant No.2184130)。
文摘PbI2/MoS2,as a typical van der Waals(vdW)heterostructure,has attracted intensive attention owing to its remarkable electronic and optoelectronic properties.In this work,the effect of defects on the electronic structures of a PbI2/MoS2 heterointerface has been systematically investigated.The manner in which the defects modulate the band structure of PbI2/MoS2,including the band gap,band edge,band alignment,and defect energy-level density within the band gap is discussed herein.It is shown that sulfur defects tune the band gaps,iodine defects shift the positions of the band edge and Fermi level,and lead defects realize the conversions between the straddling-gap band alignment and valence-band-aligned gap,thus enhancing the light-absorption ability of the material.
