Based on analysis of construction and operation of micro integrated energy systems(MIES), this paper presents economic optimization for their configuration and sizing. After presenting typical models for MIES, a resid...Based on analysis of construction and operation of micro integrated energy systems(MIES), this paper presents economic optimization for their configuration and sizing. After presenting typical models for MIES, a residential community MIES is developed by analyzing residential direct energy consumption within a general design procedure. Integrating with available current technologies and local resources, the systematic design considers a prime mover, fed by natural gas, with wind power, photovoltaic generation, and two storage devices serving thermal energy and power to satisfy cooling, heating and electricity demands. Control strategies for MIES also arepresented in this study. Multi-objective formulas are obtained by analyzing annual cost and dumped renewable energy to achieve optimal coordination of energy supply and demand. According to historical load data and the probability distribution of distributed generation output,clustering methods based on K-means and discretization methods are employed to obtain typical scenarios representative of uncertainties. The modified non-dominated sorting genetic algorithm is applied to find the Pareto frontier of the constructed multi-objective formulas. In addition, aiming to explore the Pareto frontier, the dumped energy cost ratio is defined to check the energy balance in different MIES designs and provide decision support for the investors. Finally, simulations and comparision show the appropriateness of the developed model and the applicability of the adopted optimization algorithm.展开更多
Perovskite solar cells represent a promising third-generation photovoltaic technology with low fabrication cost and high power conversion efficiency.In light of the rapid development of perovskite materials and device...Perovskite solar cells represent a promising third-generation photovoltaic technology with low fabrication cost and high power conversion efficiency.In light of the rapid development of perovskite materials and devices,a systematic survey on the latest advancements covering a broad range of related work is urgently needed.This review summarizes the recent major advances in the research of perovskite solar cells from a material science perspective.The discussed topics include the devices based on different type of perovskites(organic-inorganic hybrid,all-inorganic,and lead-free perovskite and perovskite quantum dots),the properties of perovskite defects,different type of charge transport materials(organic,polymeric,and inorganic hole transport materials and inorganic and organic electron transport materials),counter electrodes,and interfacial materials used to improve the efficiency and stability of devices.Most discussions focus on the key progresses reported within the recent five years.Meanwhile,the major issues limiting the production of perovskite solar cells and the prospects for the future development of related materials are discussed.展开更多
A series of conductive polymers, i.e., poly（3-methylthiophene） （PMT）, poly（thiophene） （PT）, poly（3-bromothiophene） （PBT） and poly（3-chlorothiophene） （PCT）, were prepared via the electrochemical polymer...A series of conductive polymers, i.e., poly（3-methylthiophene） （PMT）, poly（thiophene） （PT）, poly（3-bromothiophene） （PBT） and poly（3-chlorothiophene） （PCT）, were prepared via the electrochemical polymerization process. Subse- quently, their application as hole-transporting materials （HTMs） in CHBNI-I3Pb｜3 perovskite solar cells was explored. It was found that rationally increasing the work function of HTMs proves beneficial in improving the open circuit voltage （Voc） of the devices with an ITO/conductive-polymer/CHBNHBPbIg/C60/BCP/Ag structure. In addition, the higher-Voc devices with a higher-work-function HTM exhibited higher recombination resistances. The highest open circuit voltage of 1.04 V was obtained from devices with PCT, with a work function of -5.4 eV, as the hole-transporting layer. Its power conversion efficiency attained a value of approximately 16.5%, with a high fill factor of 0.764, an appreciable open voltage of 1.01 V and a short circuit current density of 21.4 mA.cm-2. This simple, controllable and low-cost manner of preparing HTMs will be beneficial to the production of large-area perovskite solar cells with a hole-transportin~ laver.展开更多
Ultrathin polythiophene films prepared via electrochemical polymerization is successfully used as the hole-transporting material, substituting conventional HTM-PEDOT：PSS, in planar p-i-n CH3NH3PbI3 perovskite-based s...Ultrathin polythiophene films prepared via electrochemical polymerization is successfully used as the hole-transporting material, substituting conventional HTM-PEDOT：PSS, in planar p-i-n CH3NH3PbI3 perovskite-based solar cells, affording a series of ITO/polythiophene/CH3NHBPbIB/C60/BCP/Ag devices. The ultrathin polythiophene film possesses good transmittance, high conductivity, a smooth surface, high wettability, compatibility with PbI2 DMF solution, and an energy level matching that of the CH3NH3PbI3 perovskite material. A promising power conversion efficiency of about 15.4%, featuring a high fill factor of 0.774, open voltage of 0.99 V, and short-circuit current density of 20.3 mA·cm^-2 is obtained. The overall performance of the devices is superior to that of cells using PEDOT：PSS. The differences of solar cells with different hole-transfer materials in charge recombination, charge transport and transfer, and device stability are further investigated and demonstrate that polythiophene is a more effective and promising hole-transporting material. This work provides a simple, prompt, controllable, and economic approach for the preparation of an effective hole-transporting material, which undoubtedly offers an alternative method in the future industrial production of perovskite solar cells.展开更多
An inverted planar heterojunction perovskite solar cell （PSC） is one of the most competitive photovoltaic devices exhibiting a high power conversion efficiency （PCE） and nearly free hysteresis in the voltage-curre...An inverted planar heterojunction perovskite solar cell （PSC） is one of the most competitive photovoltaic devices exhibiting a high power conversion efficiency （PCE） and nearly free hysteresis in the voltage-current output. However, the band alignment between the transport materials and the perovskite absorber has not been optimized, resulting in a lower open-circuit voltage （Voc） than that of regular PSCs. To address this issue, we tune the band alignment in perovskite photovoltaic architecture by introducing bilayer structured transport materials, e.g., the hole transport material poly（ethylenedioxythiophene）：poly（styrene sulfonate） （PEDOT：PSS）/V2Os. In this study, solution processed inorganic V2Ox interlayer is incorporated into PEDOT：PSS for achieving improved film surface properties as well as optical and electrical properties. For example, the work function （WF） was changed from 5.1 to 5.4 eV. A remarkably high PCE of 17.5% with nearly free hysteresis and a stabilized efficiency of 17.1% have been achieved. Electronic impedance spectra （EIS） demonstrate a significant increase in the recombination resistance after introducing the interlayer, associated with the high Voc output value of 1.05 V. Transient photocurrent and photovoltage measurements indicate that a comparable charge transport process and an inhibited recombination process occur in the PSC with the introduction of the V20x interlayer.展开更多
Circularly polarized organic light-emitting diode(CP-OLED) has attracted increasing interest for its efficient ability to generate circularly polarized light directly. So far, many CP-OLEDs were successfully fabricate...Circularly polarized organic light-emitting diode(CP-OLED) has attracted increasing interest for its efficient ability to generate circularly polarized light directly. So far, many CP-OLEDs were successfully fabricated with chiral emitters or chiral hosts. In this study, a new strategy based on chiral electron transporting layer is proposed to construct CP-OLEDs. A pair of chiral electron transporting materials, 1,3,5-tris((R/S)-4-isopropyl-4,5-dihydrooxazol-2-yl)benzene((R/S)-TOx^(i)Pr), are firstly designed and synthesized. The crystalline films of(R/S)-TOx^(i)Pr show circularly polarized photoluminescence with photoluminescence dissymmetry factors of-0.067 and +0.041, respectively. The CP-OLEDs based on(R/S)-TOx^(i)Pr and three types of achiral emitters all exhibit circularly polarized electroluminescence, showing feasibility and strong versatility of this new strategy. The mechanism is attributed to in-situ electrical excitation instead of simply light filtering of non-circularly polarized light. This work demonstrates a new approach for realizing circularly polarized electroluminescence which may provide a valuable strategy to develop CP-OLEDs.展开更多
For the first time in 2009,the inorganic-organic hybrid perovskite materials were applied in liquid dye-sensitized solar cells.In 2013,the power conversion efficiency successfully reached 15%,followed by great amount ...For the first time in 2009,the inorganic-organic hybrid perovskite materials were applied in liquid dye-sensitized solar cells.In 2013,the power conversion efficiency successfully reached 15%,followed by great amount of research papers bursting out.Till August 2014,the highest efficiency is certified to 17.9%,and the reported efficiency is even up to 19.3%.They quickly go beyond dye-sensitized solar cells and organic solar cells.It is expected the perovskite has its efficiency same to the single-crystal silicon cells.The“game changer”of solar cells is coming.The perovskite solar cells are cheap and easily to be made,which will benefit both science and industry.This review summarized recent development of both perovskite materials and solar cell devices,not only including new material developments of perovskite compositions,structures,and fabrication methods,but also focusing on device structures,charge transfer mechanism and stability properties of perovskite solar cells.Their perspective is also estimated.展开更多
Compared to red and green organic light-emitting diodes(OLEDs),blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency(EUE)and short excited-stat...Compared to red and green organic light-emitting diodes(OLEDs),blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency(EUE)and short excited-state lifetime.Different from the fluorescence,phosphorescence,thermally activated delayed fluorescence(TADF),and organic radical materials traditionally used in OLEDs,we demonstrate herein a new type of emitter,cerium(Ⅲ)complex Ce-1 with spin-allowed and parity-allowed d-f transition of the centre Ce^(3+) ion.The compound exhibits a high EUE up to 100% in OLEDs and a short excited-state lifetime of 42 ns,which is considerably faster than that achieved in efficient phosphorescence and TADF emitters.The optimized OLEDs show an average maximum external quantum efficiency(EQE)of 12.4% and Commission Internationale de L’Eclairage(CIE)coordinates of(0.146,0.078).展开更多
Electroluminescence of f-f transition lanthanide complex is a traditional topic for display over decades.Here we report highly efficient organic light-emitting diodes based on a new terbium(III)complex with novel liga...Electroluminescence of f-f transition lanthanide complex is a traditional topic for display over decades.Here we report highly efficient organic light-emitting diodes based on a new terbium(III)complex with novel ligand CPMIP(1-(4-cyanophenyl)-3-methyl-4-isobutyryl-pyrazoline-5-one).The high triplet energy level of CPMIP(3.0 e V)and inhibited quenching effects in the solid-state lead to a nearly 100%photoluminescent quantum efficiency of Tb(CPMIP)3.The best Tb(CPMIP)3 device exhibited maximum external quantum efficiency up to 19.7%,setting a new record of OLEDs based on f-f transition lanthanide complexes.展开更多
In the present work,we proposed an improved two-step deposition method by optimizing the reaction temperature and the dipping time for the fabrication ofperovskite films.The perovskite film fabricated at 70 ℃ exhibit...In the present work,we proposed an improved two-step deposition method by optimizing the reaction temperature and the dipping time for the fabrication ofperovskite films.The perovskite film fabricated at 70 ℃ exhibits a full surface coverage and a smooth uniform crystal morphology with a particle size up to micrometer scale.The corresponding inverted perovskite solar cell with a structure of ITO/poly（3,4-ethylenedioxythiophene）：poly（styrene-sulfonate）（PEDOT：PSS）/CH3NH3PbI3/C60/2,9-dimethyl-4,7-diphenyl-l,l 0-phenanthroline （BCP）/Ag displayed a higher power conversion efficiency（PCE）of 13.6%than that of the device fabricated at 20 ℃ （8.06%）,as well as the high reproducibility.The small but meaningful modification for two-step deposition would provide an efficient and convenient way to optimize planar perovskite solar cells and facilitate the potential applications of perovskite solar cells more widely.展开更多
Perovskite solar cells(PSCs)have attracted aggressive attention in the photovoltaic field in light of the rapid increasing power conversion efficiency.However,their large-scale application and commercialization are li...Perovskite solar cells(PSCs)have attracted aggressive attention in the photovoltaic field in light of the rapid increasing power conversion efficiency.However,their large-scale application and commercialization are limited by the toxicity issue of lead(Pb).Among all the lead-free perovskites,tin(Sn)-based perovskites have shown potential due to their low toxicity,ideal bandgap structure,high carrier mobility,and long hot carrier lifetime.Great progress of Sn-based PSCs has been realized in recent years,and the certified efficiency has now reached over 14%.Nevertheless,this record still falls far behind the theoretical calculations.This is likely due to the uncontrolled nucleation states and pronounced Sn(Ⅳ)vacancies.With insights into the methodologies resolving both issues,ligand engineering-assisted perovskite film fabrication dictates the state-of-the-art Sn-based PSCs.Herein,we summarize the role of ligand engineering during each state of film fabrication,ranging from the starting precursors to the ending fabricated bulks.The incorporation of ligands to suppress Sn~(2+)oxidation,passivate bulk defects,optimize crystal orientation,and improve stability is discussed,respectively.Finally,the remained challenges and perspectives toward advancing the performance of Sn-based PSCs are presented.We expect this review can draw a clear roadmap to facilitate Sn-based PSCs via ligand engineering.展开更多
White organic light-emitting diodes(WOLEDs)is a new generation of lighting technology and has stimulated wide-ranging studies.Despite the advantage of simple device structure,single-emitting-layer WOLEDs(SEL-WOLEDs)st...White organic light-emitting diodes(WOLEDs)is a new generation of lighting technology and has stimulated wide-ranging studies.Despite the advantage of simple device structure,single-emitting-layer WOLEDs(SEL-WOLEDs)still face the challenges of difficult material screening and fine energy level regulation.Herein,we report efficient SEL-WOLEDs with a sky-blue emitting cerium(Ⅲ)complex Ce-TBO2Et and an orange-red emitting europium(Ⅱ)complex Eu(Tp2Et)2 as the emitters,showing a maximum external quantum efficiency of 15.9%and Commission Internationale de l'Eclairage coordinates of(0.33,0.39)at various luminances.Most importantly,the electroluminescence mechanism of direct hole capture and hindered energy transfer between the two emitters facilitate a manageable weight doping concentration of 5%for Eu(Tp2Et)2,avoiding the low concentration(<1%)of the low-energy emitter in typical SEL-WOLEDs.Our results indicate that d-f transition emitters may circumvent fine energy level regulation and provide development potential for SEL-WOLEDs.展开更多
The performance of tin-based perovskite solar cells has been substantially hampered by voltage loss caused by energy level mismatch,charge recombination,energetic disorder,and other issues.Here,a fused-ring electron a...The performance of tin-based perovskite solar cells has been substantially hampered by voltage loss caused by energy level mismatch,charge recombination,energetic disorder,and other issues.Here,a fused-ring electron acceptor based on indacenodithiophene(IDIC)was for the first time introduced as a transition layer between a tin-based perovskite layer and a C 60 electron transport layer,leading to better matched energy levels in the device.In addition,coordination interactions between IDIC and perovskite improved the latter's crystallinity.The introduction of IDIC raised the power conversion efficiency from 8.98%to 11.5%and improved the device's stability.The decomposition mechanism of tin-based perovskite was also revealed by detecting the optical properties of perovskite microdomains through innovative integration of confocal laser scanning microscopy and photoluminescence spectroscopy.展开更多
Emission tunable d-f transition lanthanide complexes have wide applications in many fields such as lighting and photoredox catalysis.Compared with Ce(Ⅲ)and Eu(Ⅱ)complexes,which have achieved near-unity photoluminesc...Emission tunable d-f transition lanthanide complexes have wide applications in many fields such as lighting and photoredox catalysis.Compared with Ce(Ⅲ)and Eu(Ⅱ)complexes,which have achieved near-unity photoluminescence quantum yields(PLQYs),Yb(Ⅱ)complexes still suffer from low reported PLQYs not exceeding 10%.In this work,two luminescent Yb(Ⅱ)-containing azacryptates YbI_(2)-N8M6(N8M6=4,7,13,16,21,24-hexamethyl-1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane)and YbI2-N8E6(N8E6=4,7,13,16,21,24-hexaethyl-1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane)were synthesized and characterized.YbI2-N8M6 in solid powder exhibits blue emission with a maximum emission wavelength(λm)of 464 nm and a PLQY of 76%,while YbI_(2)-N8E6 in solid powder exhibits green emission with a λ_(m) of 537 nm and a PLQY up to93%.Moreover,YbI_(2)-N8M6 exhibits mechanochromic property,showing an emission color change from deep-blue to cyan under mechanical grinding.These results will inspire the studies about luminescent Yb(Ⅱ)complexes and their further applications.展开更多
We report the fabrication of CuI-Si heterojunction solar cells with carbon nanotubes （CNTs） as a transparent electrode. A flexible CNT network was transferred onto tile top of a polycrystalline CuI layer, making a c...We report the fabrication of CuI-Si heterojunction solar cells with carbon nanotubes （CNTs） as a transparent electrode. A flexible CNT network was transferred onto tile top of a polycrystalline CuI layer, making a conformal coating with good contact with the underlying CuI. The solar cells showed power conversion efficiencies in the range of 6% to 10.5%, while the efficiency degradation was less than 10% after the device was stored in air for 8 days. Compared with conventional rigid electrodes such as indium tin oxide （ITO） glass, the flexibility of the CNT films ensures better contact with the active layers and removes the need for press-contact electrodes. Degraded cells can recover their original performance by acid doping of the CNT electrode. Our results suggest that CNT films are suitable electrical contacts for rough materials and structures with an uneven surface.展开更多
基金supported by the Science and Technology Project of State Grid Corporation of China(No.52467K150007)
文摘Based on analysis of construction and operation of micro integrated energy systems(MIES), this paper presents economic optimization for their configuration and sizing. After presenting typical models for MIES, a residential community MIES is developed by analyzing residential direct energy consumption within a general design procedure. Integrating with available current technologies and local resources, the systematic design considers a prime mover, fed by natural gas, with wind power, photovoltaic generation, and two storage devices serving thermal energy and power to satisfy cooling, heating and electricity demands. Control strategies for MIES also arepresented in this study. Multi-objective formulas are obtained by analyzing annual cost and dumped renewable energy to achieve optimal coordination of energy supply and demand. According to historical load data and the probability distribution of distributed generation output,clustering methods based on K-means and discretization methods are employed to obtain typical scenarios representative of uncertainties. The modified non-dominated sorting genetic algorithm is applied to find the Pareto frontier of the constructed multi-objective formulas. In addition, aiming to explore the Pareto frontier, the dumped energy cost ratio is defined to check the energy balance in different MIES designs and provide decision support for the investors. Finally, simulations and comparision show the appropriateness of the developed model and the applicability of the adopted optimization algorithm.
基金supported by the National Natural Science Foundation of China(21975264,21925112,21875122,61935016,92056119,61935016,21771008)Beijing Natural Science Foundation(2191003)+1 种基金the Youth Innovation Promotion Association Chinese Academy of Sciences,the National Key Research and Development Project funding from the Ministry of Science and Technology of China(2021YFB3800100,2021YFB3800101,2020YFB1506400)the Basic and Applied Basic Research Foundation of Guangdong Province(2019B1515120083)。
文摘Perovskite solar cells represent a promising third-generation photovoltaic technology with low fabrication cost and high power conversion efficiency.In light of the rapid development of perovskite materials and devices,a systematic survey on the latest advancements covering a broad range of related work is urgently needed.This review summarizes the recent major advances in the research of perovskite solar cells from a material science perspective.The discussed topics include the devices based on different type of perovskites(organic-inorganic hybrid,all-inorganic,and lead-free perovskite and perovskite quantum dots),the properties of perovskite defects,different type of charge transport materials(organic,polymeric,and inorganic hole transport materials and inorganic and organic electron transport materials),counter electrodes,and interfacial materials used to improve the efficiency and stability of devices.Most discussions focus on the key progresses reported within the recent five years.Meanwhile,the major issues limiting the production of perovskite solar cells and the prospects for the future development of related materials are discussed.
文摘A series of conductive polymers, i.e., poly（3-methylthiophene） （PMT）, poly（thiophene） （PT）, poly（3-bromothiophene） （PBT） and poly（3-chlorothiophene） （PCT）, were prepared via the electrochemical polymerization process. Subse- quently, their application as hole-transporting materials （HTMs） in CHBNI-I3Pb｜3 perovskite solar cells was explored. It was found that rationally increasing the work function of HTMs proves beneficial in improving the open circuit voltage （Voc） of the devices with an ITO/conductive-polymer/CHBNHBPbIg/C60/BCP/Ag structure. In addition, the higher-Voc devices with a higher-work-function HTM exhibited higher recombination resistances. The highest open circuit voltage of 1.04 V was obtained from devices with PCT, with a work function of -5.4 eV, as the hole-transporting layer. Its power conversion efficiency attained a value of approximately 16.5%, with a high fill factor of 0.764, an appreciable open voltage of 1.01 V and a short circuit current density of 21.4 mA.cm-2. This simple, controllable and low-cost manner of preparing HTMs will be beneficial to the production of large-area perovskite solar cells with a hole-transportin~ laver.
基金The authors gratefully acknowledge the financial support from the National Basic Research Program （2011CB933303 and 2013CB921904） and the National Natural Science Foundation of China （NSFC） （21321001, 21371012 and 11134001）.
文摘Ultrathin polythiophene films prepared via electrochemical polymerization is successfully used as the hole-transporting material, substituting conventional HTM-PEDOT：PSS, in planar p-i-n CH3NH3PbI3 perovskite-based solar cells, affording a series of ITO/polythiophene/CH3NHBPbIB/C60/BCP/Ag devices. The ultrathin polythiophene film possesses good transmittance, high conductivity, a smooth surface, high wettability, compatibility with PbI2 DMF solution, and an energy level matching that of the CH3NH3PbI3 perovskite material. A promising power conversion efficiency of about 15.4%, featuring a high fill factor of 0.774, open voltage of 0.99 V, and short-circuit current density of 20.3 mA·cm^-2 is obtained. The overall performance of the devices is superior to that of cells using PEDOT：PSS. The differences of solar cells with different hole-transfer materials in charge recombination, charge transport and transfer, and device stability are further investigated and demonstrate that polythiophene is a more effective and promising hole-transporting material. This work provides a simple, prompt, controllable, and economic approach for the preparation of an effective hole-transporting material, which undoubtedly offers an alternative method in the future industrial production of perovskite solar cells.
基金The authors are grateful to Dr. Xinchen Li of Zolix Instruments Co., Ltd. for transient measurements and Prof. Jinglin Xie for XPS measurements. This work was supported by the National Basic Research Program of China （No. 2011CB933303） and the National Natural Science Foundation of China （NSFC） （Nos. 21321001 and 21371012）. This work was also supported by the ＂Thousand Youth Talents Plan＂, China.
文摘An inverted planar heterojunction perovskite solar cell （PSC） is one of the most competitive photovoltaic devices exhibiting a high power conversion efficiency （PCE） and nearly free hysteresis in the voltage-current output. However, the band alignment between the transport materials and the perovskite absorber has not been optimized, resulting in a lower open-circuit voltage （Voc） than that of regular PSCs. To address this issue, we tune the band alignment in perovskite photovoltaic architecture by introducing bilayer structured transport materials, e.g., the hole transport material poly（ethylenedioxythiophene）：poly（styrene sulfonate） （PEDOT：PSS）/V2Os. In this study, solution processed inorganic V2Ox interlayer is incorporated into PEDOT：PSS for achieving improved film surface properties as well as optical and electrical properties. For example, the work function （WF） was changed from 5.1 to 5.4 eV. A remarkably high PCE of 17.5% with nearly free hysteresis and a stabilized efficiency of 17.1% have been achieved. Electronic impedance spectra （EIS） demonstrate a significant increase in the recombination resistance after introducing the interlayer, associated with the high Voc output value of 1.05 V. Transient photocurrent and photovoltage measurements indicate that a comparable charge transport process and an inhibited recombination process occur in the PSC with the introduction of the V20x interlayer.
基金supported by the National Natural Science Foundation of China (92156016, U23A20593 and 22071003)the National Key R&D Program of China (2021YFB3500400, 2021YFB3501800 and 2022YFB3503700)the China Postdoctoral Science Foundation (2023TQ0004)。
文摘Circularly polarized organic light-emitting diode(CP-OLED) has attracted increasing interest for its efficient ability to generate circularly polarized light directly. So far, many CP-OLEDs were successfully fabricated with chiral emitters or chiral hosts. In this study, a new strategy based on chiral electron transporting layer is proposed to construct CP-OLEDs. A pair of chiral electron transporting materials, 1,3,5-tris((R/S)-4-isopropyl-4,5-dihydrooxazol-2-yl)benzene((R/S)-TOx^(i)Pr), are firstly designed and synthesized. The crystalline films of(R/S)-TOx^(i)Pr show circularly polarized photoluminescence with photoluminescence dissymmetry factors of-0.067 and +0.041, respectively. The CP-OLEDs based on(R/S)-TOx^(i)Pr and three types of achiral emitters all exhibit circularly polarized electroluminescence, showing feasibility and strong versatility of this new strategy. The mechanism is attributed to in-situ electrical excitation instead of simply light filtering of non-circularly polarized light. This work demonstrates a new approach for realizing circularly polarized electroluminescence which may provide a valuable strategy to develop CP-OLEDs.
基金the National Natural Science Foundation of China(Nos.61177020,11121091)the National Basic Research Program of China(No.2013CB921904).
文摘For the first time in 2009,the inorganic-organic hybrid perovskite materials were applied in liquid dye-sensitized solar cells.In 2013,the power conversion efficiency successfully reached 15%,followed by great amount of research papers bursting out.Till August 2014,the highest efficiency is certified to 17.9%,and the reported efficiency is even up to 19.3%.They quickly go beyond dye-sensitized solar cells and organic solar cells.It is expected the perovskite has its efficiency same to the single-crystal silicon cells.The“game changer”of solar cells is coming.The perovskite solar cells are cheap and easily to be made,which will benefit both science and industry.This review summarized recent development of both perovskite materials and solar cell devices,not only including new material developments of perovskite compositions,structures,and fabrication methods,but also focusing on device structures,charge transfer mechanism and stability properties of perovskite solar cells.Their perspective is also estimated.
基金the financial support from the National Key R&D Programme of China(Nos.2017YFA0205100,2016YFB0401001)the Beijing Natural Science Foundation(2202015)+1 种基金financial support from the China Postdoctoral Science Foundation(2018M641065)supported by the high-performance computing platform of Peking University.
文摘Compared to red and green organic light-emitting diodes(OLEDs),blue OLEDs are still the bottleneck due to the lack of efficient emitters with simultaneous high exciton utilization efficiency(EUE)and short excited-state lifetime.Different from the fluorescence,phosphorescence,thermally activated delayed fluorescence(TADF),and organic radical materials traditionally used in OLEDs,we demonstrate herein a new type of emitter,cerium(Ⅲ)complex Ce-1 with spin-allowed and parity-allowed d-f transition of the centre Ce^(3+) ion.The compound exhibits a high EUE up to 100% in OLEDs and a short excited-state lifetime of 42 ns,which is considerably faster than that achieved in efficient phosphorescence and TADF emitters.The optimized OLEDs show an average maximum external quantum efficiency(EQE)of 12.4% and Commission Internationale de L’Eclairage(CIE)coordinates of(0.146,0.078).
基金supported by the National Basic Research Program of China(2017YFA0205100)the Key Project of Science and Technology Plan of Beijing Education Commission(KZ201910028038)financial support from the China Postdoctoral Science Foundation(2018M641065,2021T140009)。
文摘Electroluminescence of f-f transition lanthanide complex is a traditional topic for display over decades.Here we report highly efficient organic light-emitting diodes based on a new terbium(III)complex with novel ligand CPMIP(1-(4-cyanophenyl)-3-methyl-4-isobutyryl-pyrazoline-5-one).The high triplet energy level of CPMIP(3.0 e V)and inhibited quenching effects in the solid-state lead to a nearly 100%photoluminescent quantum efficiency of Tb(CPMIP)3.The best Tb(CPMIP)3 device exhibited maximum external quantum efficiency up to 19.7%,setting a new record of OLEDs based on f-f transition lanthanide complexes.
文摘In the present work,we proposed an improved two-step deposition method by optimizing the reaction temperature and the dipping time for the fabrication ofperovskite films.The perovskite film fabricated at 70 ℃ exhibits a full surface coverage and a smooth uniform crystal morphology with a particle size up to micrometer scale.The corresponding inverted perovskite solar cell with a structure of ITO/poly（3,4-ethylenedioxythiophene）：poly（styrene-sulfonate）（PEDOT：PSS）/CH3NH3PbI3/C60/2,9-dimethyl-4,7-diphenyl-l,l 0-phenanthroline （BCP）/Ag displayed a higher power conversion efficiency（PCE）of 13.6%than that of the device fabricated at 20 ℃ （8.06%）,as well as the high reproducibility.The small but meaningful modification for two-step deposition would provide an efficient and convenient way to optimize planar perovskite solar cells and facilitate the potential applications of perovskite solar cells more widely.
基金supported by the National Natural Science Foundation of China(61935016,62275213 and 62205264),the National Natural Science Foundation of China(21961160720)the Fundamental Research Funds for Xi'an Jiaotong University(xzy012022092,xzd012022003 and xzy022022057)+1 种基金the National Key Research and Development Program of China(2022YFB3803300)the open research fund of Songshan Lake Materials Laboratory(2021SLABFK02)。
文摘Perovskite solar cells(PSCs)have attracted aggressive attention in the photovoltaic field in light of the rapid increasing power conversion efficiency.However,their large-scale application and commercialization are limited by the toxicity issue of lead(Pb).Among all the lead-free perovskites,tin(Sn)-based perovskites have shown potential due to their low toxicity,ideal bandgap structure,high carrier mobility,and long hot carrier lifetime.Great progress of Sn-based PSCs has been realized in recent years,and the certified efficiency has now reached over 14%.Nevertheless,this record still falls far behind the theoretical calculations.This is likely due to the uncontrolled nucleation states and pronounced Sn(Ⅳ)vacancies.With insights into the methodologies resolving both issues,ligand engineering-assisted perovskite film fabrication dictates the state-of-the-art Sn-based PSCs.Herein,we summarize the role of ligand engineering during each state of film fabrication,ranging from the starting precursors to the ending fabricated bulks.The incorporation of ligands to suppress Sn~(2+)oxidation,passivate bulk defects,optimize crystal orientation,and improve stability is discussed,respectively.Finally,the remained challenges and perspectives toward advancing the performance of Sn-based PSCs are presented.We expect this review can draw a clear roadmap to facilitate Sn-based PSCs via ligand engineering.
基金This work was supported by the National Natural Science Foundation of China(22071003,62104013,and 92156016)the National Key R&D PProgramof China(2021YFB3500400,2021YFB3501800,and 2022YFB3503702)the Beijing Natural Science Foundation(2202015).
文摘White organic light-emitting diodes(WOLEDs)is a new generation of lighting technology and has stimulated wide-ranging studies.Despite the advantage of simple device structure,single-emitting-layer WOLEDs(SEL-WOLEDs)still face the challenges of difficult material screening and fine energy level regulation.Herein,we report efficient SEL-WOLEDs with a sky-blue emitting cerium(Ⅲ)complex Ce-TBO2Et and an orange-red emitting europium(Ⅱ)complex Eu(Tp2Et)2 as the emitters,showing a maximum external quantum efficiency of 15.9%and Commission Internationale de l'Eclairage coordinates of(0.33,0.39)at various luminances.Most importantly,the electroluminescence mechanism of direct hole capture and hindered energy transfer between the two emitters facilitate a manageable weight doping concentration of 5%for Eu(Tp2Et)2,avoiding the low concentration(<1%)of the low-energy emitter in typical SEL-WOLEDs.Our results indicate that d-f transition emitters may circumvent fine energy level regulation and provide development potential for SEL-WOLEDs.
基金The authors gratefully acknowledge the financial support from the Beijing National Laboratory for Molecular Sciences and the National Natural Science Foundation of China(61935016 and 21771008)X.Z.thanks National Key Research and Development Program of China(2020YFB1506400).
文摘The performance of tin-based perovskite solar cells has been substantially hampered by voltage loss caused by energy level mismatch,charge recombination,energetic disorder,and other issues.Here,a fused-ring electron acceptor based on indacenodithiophene(IDIC)was for the first time introduced as a transition layer between a tin-based perovskite layer and a C 60 electron transport layer,leading to better matched energy levels in the device.In addition,coordination interactions between IDIC and perovskite improved the latter's crystallinity.The introduction of IDIC raised the power conversion efficiency from 8.98%to 11.5%and improved the device's stability.The decomposition mechanism of tin-based perovskite was also revealed by detecting the optical properties of perovskite microdomains through innovative integration of confocal laser scanning microscopy and photoluminescence spectroscopy.
基金supported by the National Natural Science Foundation of China(22071003,92156016,21621061)the National Key R&D Program of China(2021YFB3501800)Beijing Natural Science Foundation(2202015)。
文摘Emission tunable d-f transition lanthanide complexes have wide applications in many fields such as lighting and photoredox catalysis.Compared with Ce(Ⅲ)and Eu(Ⅱ)complexes,which have achieved near-unity photoluminescence quantum yields(PLQYs),Yb(Ⅱ)complexes still suffer from low reported PLQYs not exceeding 10%.In this work,two luminescent Yb(Ⅱ)-containing azacryptates YbI_(2)-N8M6(N8M6=4,7,13,16,21,24-hexamethyl-1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane)and YbI2-N8E6(N8E6=4,7,13,16,21,24-hexaethyl-1,4,7,10,13,16,21,24-octaazabicyclo[8.8.8]hexacosane)were synthesized and characterized.YbI2-N8M6 in solid powder exhibits blue emission with a maximum emission wavelength(λm)of 464 nm and a PLQY of 76%,while YbI_(2)-N8E6 in solid powder exhibits green emission with a λ_(m) of 537 nm and a PLQY up to93%.Moreover,YbI_(2)-N8M6 exhibits mechanochromic property,showing an emission color change from deep-blue to cyan under mechanical grinding.These results will inspire the studies about luminescent Yb(Ⅱ)complexes and their further applications.
基金This work is supported by the National Natural Science Foundation of China （NSFC, Grant No.50972067） and the 863 Program （No. 2009AA05Z423）. A. Cao acknowledges the support by the National Science Foundation of China （NSFC, No. 51072005） and C. Huang acknowledges NSFC No. 90922004 for financial support.
文摘We report the fabrication of CuI-Si heterojunction solar cells with carbon nanotubes （CNTs） as a transparent electrode. A flexible CNT network was transferred onto tile top of a polycrystalline CuI layer, making a conformal coating with good contact with the underlying CuI. The solar cells showed power conversion efficiencies in the range of 6% to 10.5%, while the efficiency degradation was less than 10% after the device was stored in air for 8 days. Compared with conventional rigid electrodes such as indium tin oxide （ITO） glass, the flexibility of the CNT films ensures better contact with the active layers and removes the need for press-contact electrodes. Degraded cells can recover their original performance by acid doping of the CNT electrode. Our results suggest that CNT films are suitable electrical contacts for rough materials and structures with an uneven surface.
