Two-dimensional Ruddlesden-Popper(2DRP)perovskites have attracted intense research interest for optoelectronic applications,due to their tunable optoelectronic properties and better environmental stability than their ...Two-dimensional Ruddlesden-Popper(2DRP)perovskites have attracted intense research interest for optoelectronic applications,due to their tunable optoelectronic properties and better environmental stability than their threedimensional counterparts.Furthermore,high-performance photodetectors based on single-crystal and polycrystalline thin-films 2DRP perovskites have shown great potential for practical application.However,the complex growth process of single-crystal membranes and uncontrollable phase distribution of polycrystalline films hinder the further development of 2DRP perovskites photodetectors.Herein,we report a series of high-performance photodetectors based on single-crystal-like phase-pure 2DRP perovskite films by designing a novel spacer source.Experimental and theoretical evidence demonstrates that phase-pure films substantially suppress defect states and ion migration.These highly sensitive photodetectors show I_(light)/I_(dark) ratio exceeding 3×10^(4),responsivities exceeding 16 A/W,and detectivities exceeding 3×10^(13) Jones,which are higher at least by 1 order than those of traditional mixed-phase thinfilms 2DRP devices(close to the reported single-crystal devices).More importantly,this strategy can significantly enhance the operational stability of optoelectronic devices and pave the way to large-area flexible productions.展开更多
Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allo...Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices(solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices(artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.展开更多
Quasi-2D perovskites have attracted tremendous interest for application as lightemission layers in light-emitting diodes(LEDs).However,the heterogeneous n phase and non-uniform distribution still severely limit the fu...Quasi-2D perovskites have attracted tremendous interest for application as lightemission layers in light-emitting diodes(LEDs).However,the heterogeneous n phase and non-uniform distribution still severely limit the further development of quasi-2D perovskite LEDs(Pero-LEDs).Meanwhile,the increased defect density caused by the reduced dimension and grain size induces non-radiative recombination and further deteriorates the device performance.Here,we found that a series of molecules containing phosphoryl chloride functional groups have noticeable enhancement effects on the device performance of quasi-2D Pero-LEDs.Then,we studied the modification mechanism by focusing on the bis(2-oxo-3-oxazolidinyl)phosphinic chloride(BOPCl).It is concluded that the BOPCl can not only regulate the phase distribution by decreasing the crystallization rate but also remain in the grain boundaries and passivate the defects.As a result,the corresponding quasi-2D Pero-LEDs obtained a maximum external quantum efficiency(EQE_(max))of 20.82%and an average EQE(EQE_(ave))of around 20%on the optimal 50 devices,proving excellent reproducibility.Our work provides a new selection of molecular types for regulating the crystallization and passivating the defects of quasi-2D perovskite films.展开更多
Although metal halide perovskites are increasingly popular for the next generation of efficient photovoltaic devices,the inevitable defects from the preparation process have become the notorious barrier to further imp...Although metal halide perovskites are increasingly popular for the next generation of efficient photovoltaic devices,the inevitable defects from the preparation process have become the notorious barrier to further improvement of performance,which increases non-radiative recombination and lowers the power conversion efficiency of solar cells.Surface passivation strategies have been affirmed as one of the most practical approaches to suppress these defects.Therefore,it is necessary to have a detailed review on the surface passivation to reveal the improvements of the devices.Herein,the mechanism and recent advances of surface passivation have been systematically summarized with respect to various passivation approaches,including the Lewis acid–base,the low-dimensional perovskite,inorganic molecules,and polymers.Finally,the review also offers the research trend and prospects of surface passivation.展开更多
Metal halide perovskite nanostructures have emerged as low-dimensional semiconductors of great significance in many fields such as photovoltaics,photonics,and optoelectronics.Extensive efforts on the controlled synthe...Metal halide perovskite nanostructures have emerged as low-dimensional semiconductors of great significance in many fields such as photovoltaics,photonics,and optoelectronics.Extensive efforts on the controlled synthesis of perovskite nanostructures have been made towards potential device applications.The engineering of their band structures holds great promise in the rational tuning of the electronic and optical properties of perovskite nanostructures,which is one of the keys to achieving efficient and multifunctional optoelectronic devices.In this article,we summarize recent advances in band structure engineering of perovskite nanostructures.A survey of bandgap engineering of nanostructured perovskites is firstly presented from the aspects of dimensionality tailoring,compositional substitution,phase segregation and transition,as well as strain and pressure stimuli.The strategies of electronic doping are then reviewed,including defect-induced self-doping,inorganic or organic molecules-based chemical doping,and modification by metal ions or nanostructures.Based on the bandgap engineering and electronic doping,discussions on engineering energy band alignments in perovskite nanostructures are provided for building high-performance perovskite p-n junctions and heterostructures.At last,we provide our perspectives in engineering band structures of perovskite nanostructures towards future low-energy optoelectronics technologies.展开更多
Solvent residue is inevitable to occur in solution processed thin films,but its influence on the thin film quality has not been identified and addressed to date.Methylammonium acetate(MAAc)ionic liquid has recently be...Solvent residue is inevitable to occur in solution processed thin films,but its influence on the thin film quality has not been identified and addressed to date.Methylammonium acetate(MAAc)ionic liquid has recently been realized as an environmentally friendly solvent for solution processed perovskites.The specific high viscosity,low vapor pressure and strong association with perovskite precursor of the MAAc solvent is a double-edged sword,which endowed an advantageously ambient air operational and anti-solvent free perovskite deposition,but the MAAc is likely to be retained within the film and bring in detrimental effects on device performance of the corresponding solar cells.Herein,we reported a novel route to eliminate the residual solvent via a facial hydrochloric acid(HCl)annealing post-treatment(HAAP).In particular,chemical displacement reaction between the incorporated HCl and residual MAAc can be initiated to form volatile MACl and HAc,efficiently extracting MAAc residue.In the meanwhile,the stimulated mass transport via downward penetration and upward escape can trigger secondary perovskite growth with enlarged grain size and smoothened surface,leading to reduced defect state and improved interfacial contact intimacy,and also partial chloride ions are able to enter the crystal lattice to stabilize perovskite phase structure.As a result,a champion efficiency up to20.78%originating from enhanced Voc was achieved,and more than 96%of its initial efficiency can be maintained after 1000 h shelf-storage.展开更多
Three-dimensional metal-halide perovskites have emerged as promising light harvesting materials for converting sunlight to electricity in the last few years.High power conversion efficiency of 23.3%has been demonstrat...Three-dimensional metal-halide perovskites have emerged as promising light harvesting materials for converting sunlight to electricity in the last few years.High power conversion efficiency of 23.3%has been demonstrated.However,the main challenge that currently limits the application of the perovskite solar cells is the long-term stability,which has ambient,thermal,and photo stability weaknesses.展开更多
Pb-free Sn-based perovskite solar cells(PSCs) have recently made inspiring progress, and power conversion efficiency(PCE) of 14.8% has been achieved. However, due to the energy-level mismatch and poor interfacial cont...Pb-free Sn-based perovskite solar cells(PSCs) have recently made inspiring progress, and power conversion efficiency(PCE) of 14.8% has been achieved. However, due to the energy-level mismatch and poor interfacial contact between commonly used hole transport layer(i.e., poly(3,4-ethylenedioxythio phene):poly(styrene sulfonate), PEDOT:PSS) and FASnI_(3) film, it is still challenging to effectively extract holes at the interface. Owing to the p-type nature of Sn-based perovskites, the efficient hole extraction is of particular significance to improve the PCE of their solar cells. In this work, for the first time, the role of chiral cations, a-methylbenzylamine(S-/R-/rac-MBA), in promoting hole transportation of FASnI_(3)-based PSCs is demonstrated. The introduction of MBAs is found to form 2D/3D film with lowdimensional structures locating at PEDOT:PSS/FASnI_(3) interface, which facilitates the energy level alignment and efficient charge transfer at the interface. Importantly, chiral-induced spin selectivity(CISS)effect of R-MBA_(2)SnI_(4)induced by chiral R-MBA cation is found to further assist the specific interfacial transport of accumulated holes. As a result, R-MBA-based PSCs achieve decent PCE of 10.73% with much suppressed hysteresis and enhanced device stability. This work opens up a new strategy to efficiently promote the interfacial extraction of accumulated charges in working PSCs.展开更多
Lead-free double perovskite Cs_(2)AgBiBr_(6) has gained increasing attention recently.However,the power conversion efficiency(PCE)of Cs_(2)AgBiBr_(6) perovskite solar cells(PSCs)is still low compared with their lead-b...Lead-free double perovskite Cs_(2)AgBiBr_(6) has gained increasing attention recently.However,the power conversion efficiency(PCE)of Cs_(2)AgBiBr_(6) perovskite solar cells(PSCs)is still low compared with their lead-based counterparts.Here,by using photoluminescence(PL),time-resolved photoluminescence(TRPL),and ultrafast transient absorption(TA)measurements,the unbalance between the electron and hole in diffusion and transfer,which limits the performance of the Cs_(2)AgBiBr_(6) PSCs,was further revealed.Considering this issue,a strategy of using the mesoporous TiO_(2) electron transport layer(ETL)to construct a bulk heterojunction in Cs_(2)AgBiBr_(6) PSCs was proposed.Consequently,the PCE had improved by over 24%comparing with that only used compact TiO_(2) ETL.Moreover,based on mesoporous TiO_(2),the unencapsulated Cs_(2)AgBiBr_(6) PSCs maintained 90%of their initial performance after approximately 1200 h of storage in a desiccator(humidity~30%).This work gives further understanding of Cs_(2)AgBiBr_(6) perovskite and demonstrates that a proper design of balancing the electron and hole diffusion can improve device performance.展开更多
All-inorganic metal-halide CsPbBr_(3)perovskite has emerged as an attractive photovoltaic material for its outstanding environmental stability.However,due to the wide bandgap,the performance of CsPbBr_(3)perovskite so...All-inorganic metal-halide CsPbBr_(3)perovskite has emerged as an attractive photovoltaic material for its outstanding environmental stability.However,due to the wide bandgap,the performance of CsPbBr_(3)perovskite solar cells(PSCs)is limited,especially for the short-circuit current density(J_(SC)).In this issue of Energy&Environmental Materials,Guo et al.employed Nb-doped SnO_(2)as electron transporting layers(ETLs),which could greatly improve the J_(SC)of the PSCs based on all-inorganic CsPbBr_(3).展开更多
The past few years have witnessed power conversion efficiency(PCE)of organic solar cells(OSCs)skyrocketing to the value of 20%due to the outstanding advantages of organic photoactive materials.The latter,which consist...The past few years have witnessed power conversion efficiency(PCE)of organic solar cells(OSCs)skyrocketing to the value of 20%due to the outstanding advantages of organic photoactive materials.The latter,which consist of donor and acceptor materials,indeed play important roles in OSCs,and particularly one building block has attracted considerable research attention,namely benzothiadiazole(BT).The diversity of OSCs based on the BT structure have indeed sprung up,and the progressive increase in PCE values is more than just eye-catching since it heralds a renewal and bright future of OSCs.This review analyzes significant studies that have led to these remarkable progresses and focuses on the most effective BT small-molecules and BT polymers for OSC reported in the last decades.The pivotal structure-property relationships,donor-acceptor matching criteria,and morphology control approaches are gathered and discussed in this paper.Lastly,we summarize the remaining challenges and offer a personal perspective on the future advance and improvement of OSCs.展开更多
For the process of photovoltaic conversion in organic solar cells(OSCs)and quantum-dot solar cells(QDSCs),three of four steps are determined by exciton behavior,namely,exciton generation,exciton diffusion,and exciton ...For the process of photovoltaic conversion in organic solar cells(OSCs)and quantum-dot solar cells(QDSCs),three of four steps are determined by exciton behavior,namely,exciton generation,exciton diffusion,and exciton dissociation.Therefore,it is of great importance to regulate exciton behavior in OSCs and QDSCs for achieving high power conversion efficiency.Due to the rapid development in materials and device fabrication,great progress has been made to manage the exciton behavior to achieve prolonged exciton diffusion length and improved exciton dissociation in recent years.In this review,we first introduce the parameters that affect exciton behavior,followed by the methods to measure exciton diffusion length.Then,we provide an overview of the recent advances with regard to exciton behavior investigation in OSCs and QDSCs,including exciton lifetime,exciton diffusion coefficient,and exciton dissociation.Finally,we propose future directions in deepening the understanding of exciton behavior and boosting the performance of OSCs and QDSCs.展开更多
Organic near-infrared(NIR)photodetectors with essential applications in medical diagnostics,night vision,remote sensing,and optical communications have attracted intensive research interest.Compared with most conventi...Organic near-infrared(NIR)photodetectors with essential applications in medical diagnostics,night vision,remote sensing,and optical communications have attracted intensive research interest.Compared with most conventional inorganic counterparts,organic semiconductors usually have higher absorption coefficients,and their thin active layer could be sufficient to absorb most incident light for effective photogeneration.However,due to the relatively poor charge mobility of organic materials,it remains challenging to inhibit the photogenerated exciton recombination and effectively extract carriers to their respective electrodes.Herein,this challenge was addressed by increasing matrix conductivities of a ternary active layer(D–A–D structure NIR absorber[2TT-oC6B]:poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidin[PolyTPD]:[6,6]-phenyl-C61-butyric acid methyl ester[PCBM]=1:1:1)upon in situ incident light illumination,significantly accelerating charge transport through percolated interpenetrating paths.The greatly enhanced photoconductivity under illumination is intrinsically related to the unique donor–acceptor molecular structures of PolyTPD and 2TT-oC6B,whereas stable intermolecular interaction has been verified by systematic molecular dynamics simulation.In addition,an ultrafast charge transfer time of 0.56 ps from the NIR aggregation-induced luminogens of 2TT-oC6B absorber to PolyTPD and PCBM measured by femtosecond transient absorption spectroscopy is beneficial for effective exciton dissociation.The solution-processed organic NIR photodetector exhibits a fast response time of 83μs and a linear dynamic range value of 111 dB under illumination of 830 nm.Therefore,our work has opened up a pioneering window to enhance photoconductivity through in situ photoirradiation and benefit NIR photodetectors as well as other optoelectronic devices.展开更多
有机-无机杂化二维ruddlesden-popper(RP)钙钛矿因为其优异的光电性能和良好的稳定性,在太阳能电池和发光器件领域应用前景巨大,而受到广泛关注.最近,人们提出一类新型的二维RP相全无机钙钛矿Cs2PbI2Cl2材料,这类材料具有优异的激子吸...有机-无机杂化二维ruddlesden-popper(RP)钙钛矿因为其优异的光电性能和良好的稳定性,在太阳能电池和发光器件领域应用前景巨大,而受到广泛关注.最近,人们提出一类新型的二维RP相全无机钙钛矿Cs2PbI2Cl2材料,这类材料具有优异的激子吸收性能以及良好的环境和热稳定性.本文报道了Cs2PbI2Cl2中有趣的光致相变和光致变色现象.在低功率连续激光激发下,Cs2PbI2Cl2的室温光致发光以412 nm处的微弱的紫色发射为主.有趣的是,随着激发功率的增加,发射颜色逐渐由紫色变为明亮的红色.这种光致变色起源于Cs2P b I2C l2晶体内由热能驱动的光致相变而形成的CsPbI3纳米晶.由于Cs2PbI2Cl2基体微晶的保护作用,内嵌的CsPbI3纳米晶的稳定性相比于纯的CsPbI3有明显提高.而具有光致变色特征的Cs2PbI2Cl2可能会在光学加密中得到应用,这在本项工作中得到了初步证实.展开更多
Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conv...Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conversion efficiency(PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)3 and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)3 solar cells and outline possible directions to further improve the device performance.展开更多
Environment-friendly protic amine carboxylic acid ionic liquids(ILs)as solvents is a significant breakthrough with respect to traditional highly coordinating and toxic solvents in achieving efficient and stable perovs...Environment-friendly protic amine carboxylic acid ionic liquids(ILs)as solvents is a significant breakthrough with respect to traditional highly coordinating and toxic solvents in achieving efficient and stable perovskite solar cells(PSCs)with a simple one-step air processing and without an antisolvent treatment approach.However,it remains mysterious for the improved efficiency and stability of PSCs without any passivation strategy.Here,we unambiguously demonstrate that the three functions of solvents,additive,and passivation are present for protic amine carboxylic acid ILs.We found that the ILs have the capability to dissolve a series of perovskite precursors,induce oriented crystallization,and chemically passivate the grain boundaries.This is attributed to the unique molecular structure of ILs with carbonyl and amine groups,allowing for strong interaction with perovskite precursors by forming C=O…Pb chelate bonds and N-H…I hydrogen bonds in both solution and film.This finding is generic in nature with extension to a wide range of IL-based perovskite optoelectronics.展开更多
Heavily doped colloidal plasmonic nanocrystals have attracted great attention because of their lower and adjustable free carrier densities and tunable localized surface plasmonic resonance bands in the spectral range ...Heavily doped colloidal plasmonic nanocrystals have attracted great attention because of their lower and adjustable free carrier densities and tunable localized surface plasmonic resonance bands in the spectral range from near-infra to mid-infra wavelengths.With its plasmon-enhanced optical nonlinearity,this new family of plasmonic materials shows a huge potential for nonlinear optical applications,such as ultrafast switching,nonlinear sensing,and pulse laser generation.Cu3-xP nanocrystals were previously shown to have a strong saturable absorption at the plasmonic resonance,which enabled high-energy Q-switched fiber lasers with 6.1μs pulse duration.This work demonstrates that both high-quality mode-locked and Q-switched pulses at 1560 nm can be generated by evanescently incorporating two-dimensional(2D)Cu3-xP nanocrystals onto a D-shaped optical fiber as an effective saturable absorber.The 3 dB bandwidth of the mode-locking optical spectrum is as broad as 7.3 nm,and the corresponding pulse duration can reach 423 fs.The repetition rate of the Q-switching pulses is higher than 80 kHz.Moreover,the largest pulse energy is more than 120μJ.Note that laser characteristics are highly stable and repeatable based on the results of over 20 devices.This work may trigger further investigations on heavily doped plasmonic 2D nanocrystals as a next-generation,inexpensive,and solution-processed element for fascinating photonics and optoelectronics applications.展开更多
The ultrafast monitoring of deoxyribonucleic acid(DNA)dynamic structural changes is an emerging and rapidly growing research topic in biotechnology.The existing optical spectroscopy used to identify different dynamica...The ultrafast monitoring of deoxyribonucleic acid(DNA)dynamic structural changes is an emerging and rapidly growing research topic in biotechnology.The existing optical spectroscopy used to identify different dynamical DNA structures lacks quick response while requiring large consumption of samples and bulky instrumental facilities.It is highly demanded to develop an ultrafast technique that monitors DNA structural changes with the external stimulus or cancer-related disease scenarios.Here,we demonstrate a novel photonic integrated graphene-optofluidic device to monitor DNA structural changes with the ultrafast response time.Our approach is featured with an effective and straightforward design of decoding the electronic structure change of graphene induced by its interactions with DNAs in different conformations using ultrafast nanosecond pulse laser and achieving refractive index sensitivity of~3×10^(−5) RIU.This innovative technique for the first time allows us to perform ultrafast monitoring of the conformational changes of special DNA molecules structures,including G-quadruplex formation by K+ions and i-motif formation by the low pH stimulus.The graphene-optofluidic device as presented here provides a new class of label-free,ultrafast,ultrasensitive,compact,and cost-effective optical biosensors for medical and healthcare applications.展开更多
Metal halide perovskite materials have been widely studied recently due to their excellent optoelectronic properties.Among these materials,organic-inorganic hybrid perovskites have attracted much attention because of ...Metal halide perovskite materials have been widely studied recently due to their excellent optoelectronic properties.Among these materials,organic-inorganic hybrid perovskites have attracted much attention because of their relatively soft framework,which makes them more suitable for nonlinear optical(NLO)applications.However,there is rare physical mechanism study on the coexistence of two-photon absorption(TPA)and saturable absorption(SA)in organic-inorganic hybrid perovskite materials.To clarify this issue,the NLO properties of mixed cation perovskite MA1-xFAxPbI3[MA=CH3NH3,FA=CH(NH2)2,x=0,0.2,0.4,0.6,and 0.8]thin films are investigated in this paper.Based on the nonlinear transmittance and femtosecond-transient absorption spectrum measurements,it is found that the MA1-xFAxPbI3 materials exhibit NLO behavior dependent on excitation intensity.The TPA coefficient of MA1-xFAxPbI3 decreases with the increase of formamidinium(FA)content,while the relevant saturable intensity increases.In addition,it is revealed that the linear absorption process from valence band 2 to valance band 1 still exists even under a very low excitation intensity.With the increase of excitation intensity,the light transmittance at 1300 nm decreases first and then increases sharply,which also supports the explanation for the coexistence of TPA and SA.It is expected that our findings will promote the application of perovskite materials in nonlinear optoelectronic devices.展开更多
Although multiple emissive phosphors are of great fundamental interest and practical importance,it is still challenging to achieve full-color tunable luminescence in a single-component material.Herein,we present an an...Although multiple emissive phosphors are of great fundamental interest and practical importance,it is still challenging to achieve full-color tunable luminescence in a single-component material.Herein,we present an antimony-doped lead halide single crystal(C10NH22)2PbBr4:Sb3+with widely tunable red/green/blue/white luminescence.Extrinsic Sb3+dopants provide host another active sites to capture photo-generated excitons,thus triggering blue/red dual emission.Moreover,a reversible thermal-induced phase transition transforms blue/red emission into green/red dual emission.Both two phases exhibit intriguing excitation-wavelength dependent emission,affording a whole color gamut covering the red-green-blue(RGB)color triangle on the CIE 1931 diagram.Experimental and theoretical calculation studies reveal two emitters work independently,which paves the way for the multimode optical control and promotes the development of multifunctional luminescent materials.展开更多
基金Shenzhen-Hong Kong-Macao Science and Technology Innovation Project(Category C),Grant/Award Number:SGDX2020110309360100Fundo para o Desenvolvimento das Ciências e da Tecnologia,Grant/Award Numbers:FDCT-0044/2020/A1,0034/2021/APD+3 种基金Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials,Grant/Award Number:2019B121205002Natural Science Foundation of Guangdong Province,Grant/Award Number:2019A1515012186National Natural Science Foundation of China,Grant/Award Numbers:61935017,62175268,62105292UM's research fund,Grant/Award Numbers:MYRG2018-00148-IAPME,MYRG2020-00151-IAPME。
文摘Two-dimensional Ruddlesden-Popper(2DRP)perovskites have attracted intense research interest for optoelectronic applications,due to their tunable optoelectronic properties and better environmental stability than their threedimensional counterparts.Furthermore,high-performance photodetectors based on single-crystal and polycrystalline thin-films 2DRP perovskites have shown great potential for practical application.However,the complex growth process of single-crystal membranes and uncontrollable phase distribution of polycrystalline films hinder the further development of 2DRP perovskites photodetectors.Herein,we report a series of high-performance photodetectors based on single-crystal-like phase-pure 2DRP perovskite films by designing a novel spacer source.Experimental and theoretical evidence demonstrates that phase-pure films substantially suppress defect states and ion migration.These highly sensitive photodetectors show I_(light)/I_(dark) ratio exceeding 3×10^(4),responsivities exceeding 16 A/W,and detectivities exceeding 3×10^(13) Jones,which are higher at least by 1 order than those of traditional mixed-phase thinfilms 2DRP devices(close to the reported single-crystal devices).More importantly,this strategy can significantly enhance the operational stability of optoelectronic devices and pave the way to large-area flexible productions.
基金the National Key Research and Development Program of China (2022YFB3803300)the open research fund of Songshan Lake Materials Laboratory (2021SLABFK02)the National Natural Science Foundation of China (21961160720)。
文摘Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices(solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices(artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.
基金supported by the National Natural Science Foundation of China(U21A2078)Natural Science Foundation of Fujian Province(2020J06021,2019J01057,and 2020J01064)Scientific Research Funds of Huaqiao University.
文摘Quasi-2D perovskites have attracted tremendous interest for application as lightemission layers in light-emitting diodes(LEDs).However,the heterogeneous n phase and non-uniform distribution still severely limit the further development of quasi-2D perovskite LEDs(Pero-LEDs).Meanwhile,the increased defect density caused by the reduced dimension and grain size induces non-radiative recombination and further deteriorates the device performance.Here,we found that a series of molecules containing phosphoryl chloride functional groups have noticeable enhancement effects on the device performance of quasi-2D Pero-LEDs.Then,we studied the modification mechanism by focusing on the bis(2-oxo-3-oxazolidinyl)phosphinic chloride(BOPCl).It is concluded that the BOPCl can not only regulate the phase distribution by decreasing the crystallization rate but also remain in the grain boundaries and passivate the defects.As a result,the corresponding quasi-2D Pero-LEDs obtained a maximum external quantum efficiency(EQE_(max))of 20.82%and an average EQE(EQE_(ave))of around 20%on the optimal 50 devices,proving excellent reproducibility.Our work provides a new selection of molecular types for regulating the crystallization and passivating the defects of quasi-2D perovskite films.
基金The authors acknowledge the Science and Technology Development Fund,Macao SAR(File no.FDCT-0044/2020/A1,FDCT-091/2017/A2,FDCT-014/2017/AMJ,and FDCT-0163/2019/A3),UM’s research fund(File no.MYRG2018-00148-IAPME and SRG2019-00179-IAPME)the Natural Science Foundation of China(61935017,22022309,and 62105292),Natural Science Foundation of Guang-dong Province,China(2019A1515012186 and 2021A1515010024)+2 种基金Shenzhen-Hong Kong-Macao Science and Technology Innovation Project(Category C)(SGDX2020110309360100)Guangdong-Hong Kong-Macao Joint Labora-tory of Optoelectronic and Magnetic Functional Materials(2019B121205002)S.Mei thanks financial support from the Natural Science Foundation of China(62004231).
文摘Although metal halide perovskites are increasingly popular for the next generation of efficient photovoltaic devices,the inevitable defects from the preparation process have become the notorious barrier to further improvement of performance,which increases non-radiative recombination and lowers the power conversion efficiency of solar cells.Surface passivation strategies have been affirmed as one of the most practical approaches to suppress these defects.Therefore,it is necessary to have a detailed review on the surface passivation to reveal the improvements of the devices.Herein,the mechanism and recent advances of surface passivation have been systematically summarized with respect to various passivation approaches,including the Lewis acid–base,the low-dimensional perovskite,inorganic molecules,and polymers.Finally,the review also offers the research trend and prospects of surface passivation.
基金support from Australian Research Council (ARC, FT150100450, IH150100006 and CE170100039)support from the MCATM and the FLEET+1 种基金the support from Shenzhen Nanshan District Pilotage Team Program (LHTD20170006)support from Guangzhou Science and Technology Program (Grant No. 201804010322)
文摘Metal halide perovskite nanostructures have emerged as low-dimensional semiconductors of great significance in many fields such as photovoltaics,photonics,and optoelectronics.Extensive efforts on the controlled synthesis of perovskite nanostructures have been made towards potential device applications.The engineering of their band structures holds great promise in the rational tuning of the electronic and optical properties of perovskite nanostructures,which is one of the keys to achieving efficient and multifunctional optoelectronic devices.In this article,we summarize recent advances in band structure engineering of perovskite nanostructures.A survey of bandgap engineering of nanostructured perovskites is firstly presented from the aspects of dimensionality tailoring,compositional substitution,phase segregation and transition,as well as strain and pressure stimuli.The strategies of electronic doping are then reviewed,including defect-induced self-doping,inorganic or organic molecules-based chemical doping,and modification by metal ions or nanostructures.Based on the bandgap engineering and electronic doping,discussions on engineering energy band alignments in perovskite nanostructures are provided for building high-performance perovskite p-n junctions and heterostructures.At last,we provide our perspectives in engineering band structures of perovskite nanostructures towards future low-energy optoelectronics technologies.
基金financially supported by the National Natural Science Foundation of China(Grants 51972172,61705102,61605073,61935017 and 91833304)Projects of International Cooperation and Exchanges NSFC(51811530018)+3 种基金the Young 1000 Talents Global Recruitment Program of Chinathe Jiangsu Specially Appointed Professor Program“Six talent peaks”Project in Jiangsu Province,Chinathe fellowship of China Postdoctoral Science Foundation(2020M672181)。
文摘Solvent residue is inevitable to occur in solution processed thin films,but its influence on the thin film quality has not been identified and addressed to date.Methylammonium acetate(MAAc)ionic liquid has recently been realized as an environmentally friendly solvent for solution processed perovskites.The specific high viscosity,low vapor pressure and strong association with perovskite precursor of the MAAc solvent is a double-edged sword,which endowed an advantageously ambient air operational and anti-solvent free perovskite deposition,but the MAAc is likely to be retained within the film and bring in detrimental effects on device performance of the corresponding solar cells.Herein,we reported a novel route to eliminate the residual solvent via a facial hydrochloric acid(HCl)annealing post-treatment(HAAP).In particular,chemical displacement reaction between the incorporated HCl and residual MAAc can be initiated to form volatile MACl and HAc,efficiently extracting MAAc residue.In the meanwhile,the stimulated mass transport via downward penetration and upward escape can trigger secondary perovskite growth with enlarged grain size and smoothened surface,leading to reduced defect state and improved interfacial contact intimacy,and also partial chloride ions are able to enter the crystal lattice to stabilize perovskite phase structure.As a result,a champion efficiency up to20.78%originating from enhanced Voc was achieved,and more than 96%of its initial efficiency can be maintained after 1000 h shelf-storage.
基金The authors acknowledge the financial support from Macao Science and Technology Development Funds(FDCT-116/2016/A3,FDCT-091/2017/A2,FDCT-014/2017/AMJ)Research Grants(SRG2016-00087-FST,MYRG2018-00148-IAPME)from University of Macao,the Natural Science Foundation of China(91733302,61605073,2015CB932200)the Young 1000 Talents Global Recruitment Program of China.
文摘Three-dimensional metal-halide perovskites have emerged as promising light harvesting materials for converting sunlight to electricity in the last few years.High power conversion efficiency of 23.3%has been demonstrated.However,the main challenge that currently limits the application of the perovskite solar cells is the long-term stability,which has ambient,thermal,and photo stability weaknesses.
基金financially supported by the Natural Science Foundation of China (Grants 51802253, 51972172, 61705102,61904152, and 91833304)the China Postdoctoral Science Foundation (Grant 2021M692630)+6 种基金the Natural Science Basic Research Plan in Shaanxi Province of China (2019JM-326)the Joint Research Funds of Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University (No. 2020GXLH-Z-007)the Natural Science Foundation of Jiangsu Province for Distinguished Young Scholars,China (Grant BK20200034)the Young 1000 Talents Global Recruitment Program of Chinathe Jiangsu Specially Appointed Professor programthe “Six talent peaks” Project in Jiangsu Province,Chinathe Fundamental Research Funds for the Central Universities。
文摘Pb-free Sn-based perovskite solar cells(PSCs) have recently made inspiring progress, and power conversion efficiency(PCE) of 14.8% has been achieved. However, due to the energy-level mismatch and poor interfacial contact between commonly used hole transport layer(i.e., poly(3,4-ethylenedioxythio phene):poly(styrene sulfonate), PEDOT:PSS) and FASnI_(3) film, it is still challenging to effectively extract holes at the interface. Owing to the p-type nature of Sn-based perovskites, the efficient hole extraction is of particular significance to improve the PCE of their solar cells. In this work, for the first time, the role of chiral cations, a-methylbenzylamine(S-/R-/rac-MBA), in promoting hole transportation of FASnI_(3)-based PSCs is demonstrated. The introduction of MBAs is found to form 2D/3D film with lowdimensional structures locating at PEDOT:PSS/FASnI_(3) interface, which facilitates the energy level alignment and efficient charge transfer at the interface. Importantly, chiral-induced spin selectivity(CISS)effect of R-MBA_(2)SnI_(4)induced by chiral R-MBA cation is found to further assist the specific interfacial transport of accumulated holes. As a result, R-MBA-based PSCs achieve decent PCE of 10.73% with much suppressed hysteresis and enhanced device stability. This work opens up a new strategy to efficiently promote the interfacial extraction of accumulated charges in working PSCs.
基金financial support from Macao Science and Technology Development Fund,China(FDCT-0044/2020/A1,FDCT-091/2017/A2,FDCT-014/2017/AMJ)University of Macao Research Grant,China(MYRG2018-00148-IAPME,MYRG2018-00142-IAPME)from University of Macao+2 种基金the Natural Science Foundation of China,China(91733302,61935017)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials(2019B121205002)Natural Science Foundation of Guangdong Province,China(2019A1515012186).
文摘Lead-free double perovskite Cs_(2)AgBiBr_(6) has gained increasing attention recently.However,the power conversion efficiency(PCE)of Cs_(2)AgBiBr_(6) perovskite solar cells(PSCs)is still low compared with their lead-based counterparts.Here,by using photoluminescence(PL),time-resolved photoluminescence(TRPL),and ultrafast transient absorption(TA)measurements,the unbalance between the electron and hole in diffusion and transfer,which limits the performance of the Cs_(2)AgBiBr_(6) PSCs,was further revealed.Considering this issue,a strategy of using the mesoporous TiO_(2) electron transport layer(ETL)to construct a bulk heterojunction in Cs_(2)AgBiBr_(6) PSCs was proposed.Consequently,the PCE had improved by over 24%comparing with that only used compact TiO_(2) ETL.Moreover,based on mesoporous TiO_(2),the unencapsulated Cs_(2)AgBiBr_(6) PSCs maintained 90%of their initial performance after approximately 1200 h of storage in a desiccator(humidity~30%).This work gives further understanding of Cs_(2)AgBiBr_(6) perovskite and demonstrates that a proper design of balancing the electron and hole diffusion can improve device performance.
基金the Science and Technology Development Fund,Macao SAR(File no.FDCT-0044/2020/A1,FDCT-091/2017/A2,FDCT-014/2017/AMJ)UM’s research fund(File no.MYRG2018-00148-IAPME)+2 种基金the Natural Science Foundation of China(61935017)Natural Science Foundation of Guangdong Province,China(2019A1515012186)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials(2019B121205002)
文摘All-inorganic metal-halide CsPbBr_(3)perovskite has emerged as an attractive photovoltaic material for its outstanding environmental stability.However,due to the wide bandgap,the performance of CsPbBr_(3)perovskite solar cells(PSCs)is limited,especially for the short-circuit current density(J_(SC)).In this issue of Energy&Environmental Materials,Guo et al.employed Nb-doped SnO_(2)as electron transporting layers(ETLs),which could greatly improve the J_(SC)of the PSCs based on all-inorganic CsPbBr_(3).
基金Major Program of Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,China(No.19KJA460005)Special Science and Technology Innovation Fund of Jiangsu Province on Carbon Peak and Carbon Neutralization-Frontier Fundamental Project(No.BK20220010).
文摘The past few years have witnessed power conversion efficiency(PCE)of organic solar cells(OSCs)skyrocketing to the value of 20%due to the outstanding advantages of organic photoactive materials.The latter,which consist of donor and acceptor materials,indeed play important roles in OSCs,and particularly one building block has attracted considerable research attention,namely benzothiadiazole(BT).The diversity of OSCs based on the BT structure have indeed sprung up,and the progressive increase in PCE values is more than just eye-catching since it heralds a renewal and bright future of OSCs.This review analyzes significant studies that have led to these remarkable progresses and focuses on the most effective BT small-molecules and BT polymers for OSC reported in the last decades.The pivotal structure-property relationships,donor-acceptor matching criteria,and morphology control approaches are gathered and discussed in this paper.Lastly,we summarize the remaining challenges and offer a personal perspective on the future advance and improvement of OSCs.
基金The authors thank the National Natural Science Foundation of China(Nos.52173189,22105208,61935017)Hunan Provincial Natural Science Foundation of China(No.2022JJ40570)+2 种基金the Science and Technology Development Fund,Macao SAR(No.FDCT-0044/2020/A1)UM's Research Fund(No.MYRG2020-00151-IAPME)Shenzhen Institute of Advanced Technology,and the Chinese Academy of Sciences for financial support.
文摘For the process of photovoltaic conversion in organic solar cells(OSCs)and quantum-dot solar cells(QDSCs),three of four steps are determined by exciton behavior,namely,exciton generation,exciton diffusion,and exciton dissociation.Therefore,it is of great importance to regulate exciton behavior in OSCs and QDSCs for achieving high power conversion efficiency.Due to the rapid development in materials and device fabrication,great progress has been made to manage the exciton behavior to achieve prolonged exciton diffusion length and improved exciton dissociation in recent years.In this review,we first introduce the parameters that affect exciton behavior,followed by the methods to measure exciton diffusion length.Then,we provide an overview of the recent advances with regard to exciton behavior investigation in OSCs and QDSCs,including exciton lifetime,exciton diffusion coefficient,and exciton dissociation.Finally,we propose future directions in deepening the understanding of exciton behavior and boosting the performance of OSCs and QDSCs.
基金National Natural Science Foundation of China,Grant/Award Numbers:21788102,03012800001Research Grants Council of Hong Kong,Grant/Award Numbers:16307020,16305518,16305618,C6014-20W+3 种基金Innovation and Technology Commission,Grant/Award Number:ITC-CNERC14SC01Shenzhen Science and Technology Innovation Committee,Grant/Award Numbers:JCYJ20190809172615277,GJHZ20210705143204013Science and Technology Development Fund of Macao SAR,Grant/Award Number:FDCT-0044/2020/A1Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2020A1515111065。
文摘Organic near-infrared(NIR)photodetectors with essential applications in medical diagnostics,night vision,remote sensing,and optical communications have attracted intensive research interest.Compared with most conventional inorganic counterparts,organic semiconductors usually have higher absorption coefficients,and their thin active layer could be sufficient to absorb most incident light for effective photogeneration.However,due to the relatively poor charge mobility of organic materials,it remains challenging to inhibit the photogenerated exciton recombination and effectively extract carriers to their respective electrodes.Herein,this challenge was addressed by increasing matrix conductivities of a ternary active layer(D–A–D structure NIR absorber[2TT-oC6B]:poly(N,N′-bis-4-butylphenyl-N,N′-bisphenyl)benzidin[PolyTPD]:[6,6]-phenyl-C61-butyric acid methyl ester[PCBM]=1:1:1)upon in situ incident light illumination,significantly accelerating charge transport through percolated interpenetrating paths.The greatly enhanced photoconductivity under illumination is intrinsically related to the unique donor–acceptor molecular structures of PolyTPD and 2TT-oC6B,whereas stable intermolecular interaction has been verified by systematic molecular dynamics simulation.In addition,an ultrafast charge transfer time of 0.56 ps from the NIR aggregation-induced luminogens of 2TT-oC6B absorber to PolyTPD and PCBM measured by femtosecond transient absorption spectroscopy is beneficial for effective exciton dissociation.The solution-processed organic NIR photodetector exhibits a fast response time of 83μs and a linear dynamic range value of 111 dB under illumination of 830 nm.Therefore,our work has opened up a pioneering window to enhance photoconductivity through in situ photoirradiation and benefit NIR photodetectors as well as other optoelectronic devices.
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)。
文摘有机-无机杂化二维ruddlesden-popper(RP)钙钛矿因为其优异的光电性能和良好的稳定性,在太阳能电池和发光器件领域应用前景巨大,而受到广泛关注.最近,人们提出一类新型的二维RP相全无机钙钛矿Cs2PbI2Cl2材料,这类材料具有优异的激子吸收性能以及良好的环境和热稳定性.本文报道了Cs2PbI2Cl2中有趣的光致相变和光致变色现象.在低功率连续激光激发下,Cs2PbI2Cl2的室温光致发光以412 nm处的微弱的紫色发射为主.有趣的是,随着激发功率的增加,发射颜色逐渐由紫色变为明亮的红色.这种光致变色起源于Cs2P b I2C l2晶体内由热能驱动的光致相变而形成的CsPbI3纳米晶.由于Cs2PbI2Cl2基体微晶的保护作用,内嵌的CsPbI3纳米晶的稳定性相比于纯的CsPbI3有明显提高.而具有光致变色特征的Cs2PbI2Cl2可能会在光学加密中得到应用,这在本项工作中得到了初步证实.
基金the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21572041 and 21772030)for the financial support
文摘Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conversion efficiency(PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)3 and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)3 solar cells and outline possible directions to further improve the device performance.
基金This work was financially supported by the Natural Science Foundation of China(Grants 51972172,61705102,and 91833304)the Natural Science Basic Research Plan in Shaanxi Province of China(2019JM-326)+2 种基金the Young 1000 Talents Global Recruitment Program of Chinathe Fundamental Research Funds for the Central UniversitiesThis work also was financially supported by the National Key Research and Development Program of China(grant no.2017YFA0403400).
文摘Environment-friendly protic amine carboxylic acid ionic liquids(ILs)as solvents is a significant breakthrough with respect to traditional highly coordinating and toxic solvents in achieving efficient and stable perovskite solar cells(PSCs)with a simple one-step air processing and without an antisolvent treatment approach.However,it remains mysterious for the improved efficiency and stability of PSCs without any passivation strategy.Here,we unambiguously demonstrate that the three functions of solvents,additive,and passivation are present for protic amine carboxylic acid ILs.We found that the ILs have the capability to dissolve a series of perovskite precursors,induce oriented crystallization,and chemically passivate the grain boundaries.This is attributed to the unique molecular structure of ILs with carbonyl and amine groups,allowing for strong interaction with perovskite precursors by forming C=O…Pb chelate bonds and N-H…I hydrogen bonds in both solution and film.This finding is generic in nature with extension to a wide range of IL-based perovskite optoelectronics.
基金the support from the National Key Research&Development Program(No.2016YFA0201902)Shenzhen Nanshan District Pilotage Team Program(No.LHTD20170006)+1 种基金Australian Research Council(ARC,FT 150100450,IH150100006,and CE170100039)the funding support from China Postdoctoral Science Foundation Grant(No.217M622758).
文摘Heavily doped colloidal plasmonic nanocrystals have attracted great attention because of their lower and adjustable free carrier densities and tunable localized surface plasmonic resonance bands in the spectral range from near-infra to mid-infra wavelengths.With its plasmon-enhanced optical nonlinearity,this new family of plasmonic materials shows a huge potential for nonlinear optical applications,such as ultrafast switching,nonlinear sensing,and pulse laser generation.Cu3-xP nanocrystals were previously shown to have a strong saturable absorption at the plasmonic resonance,which enabled high-energy Q-switched fiber lasers with 6.1μs pulse duration.This work demonstrates that both high-quality mode-locked and Q-switched pulses at 1560 nm can be generated by evanescently incorporating two-dimensional(2D)Cu3-xP nanocrystals onto a D-shaped optical fiber as an effective saturable absorber.The 3 dB bandwidth of the mode-locking optical spectrum is as broad as 7.3 nm,and the corresponding pulse duration can reach 423 fs.The repetition rate of the Q-switching pulses is higher than 80 kHz.Moreover,the largest pulse energy is more than 120μJ.Note that laser characteristics are highly stable and repeatable based on the results of over 20 devices.This work may trigger further investigations on heavily doped plasmonic 2D nanocrystals as a next-generation,inexpensive,and solution-processed element for fascinating photonics and optoelectronics applications.
基金from the National Natural Science Foundation of China(21874096,21575095,51602305,61604102 and 61875139)the 111 Project,and the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)+2 种基金the China Postdoctoral Science Foundation(2018M633118)Shenzhen Nanshan District Pilotage Team Program(LHTD20170006)Australian Research Council(ARC,FT150100450,IH150100006 and CE170100039).Q.Bao acknowledges support from the Australian Research Council(ARC)Centre of Excellence in Future Low-Energy Electronics Technologies(FLEET).
文摘The ultrafast monitoring of deoxyribonucleic acid(DNA)dynamic structural changes is an emerging and rapidly growing research topic in biotechnology.The existing optical spectroscopy used to identify different dynamical DNA structures lacks quick response while requiring large consumption of samples and bulky instrumental facilities.It is highly demanded to develop an ultrafast technique that monitors DNA structural changes with the external stimulus or cancer-related disease scenarios.Here,we demonstrate a novel photonic integrated graphene-optofluidic device to monitor DNA structural changes with the ultrafast response time.Our approach is featured with an effective and straightforward design of decoding the electronic structure change of graphene induced by its interactions with DNAs in different conformations using ultrafast nanosecond pulse laser and achieving refractive index sensitivity of~3×10^(−5) RIU.This innovative technique for the first time allows us to perform ultrafast monitoring of the conformational changes of special DNA molecules structures,including G-quadruplex formation by K+ions and i-motif formation by the low pH stimulus.The graphene-optofluidic device as presented here provides a new class of label-free,ultrafast,ultrasensitive,compact,and cost-effective optical biosensors for medical and healthcare applications.
基金National Natural Science Foundation of China(61605073,61935017,91733302)Universidade de Macao(MYRG2018-00148-IAPME)+1 种基金The Science and Technology Development Fund(091/2017/A2)Science,Technology and Innovation Commission of Shenzhen Municipality(JCYJ20180305180553701,JCYJ20190808121211510,KQTD2015071710313656)。
文摘Metal halide perovskite materials have been widely studied recently due to their excellent optoelectronic properties.Among these materials,organic-inorganic hybrid perovskites have attracted much attention because of their relatively soft framework,which makes them more suitable for nonlinear optical(NLO)applications.However,there is rare physical mechanism study on the coexistence of two-photon absorption(TPA)and saturable absorption(SA)in organic-inorganic hybrid perovskite materials.To clarify this issue,the NLO properties of mixed cation perovskite MA1-xFAxPbI3[MA=CH3NH3,FA=CH(NH2)2,x=0,0.2,0.4,0.6,and 0.8]thin films are investigated in this paper.Based on the nonlinear transmittance and femtosecond-transient absorption spectrum measurements,it is found that the MA1-xFAxPbI3 materials exhibit NLO behavior dependent on excitation intensity.The TPA coefficient of MA1-xFAxPbI3 decreases with the increase of formamidinium(FA)content,while the relevant saturable intensity increases.In addition,it is revealed that the linear absorption process from valence band 2 to valance band 1 still exists even under a very low excitation intensity.With the increase of excitation intensity,the light transmittance at 1300 nm decreases first and then increases sharply,which also supports the explanation for the coexistence of TPA and SA.It is expected that our findings will promote the application of perovskite materials in nonlinear optoelectronic devices.
基金supported by the Science and Technology Development Fund,Macao SAR (File no.FDCT-0044/2020/A1,0082/2021/A2)UM’s research fund (File no.MYRG2018-00148-IAPME,MYRG2020-00151-IAPME,MYRG2018-00142-IAPME)+3 种基金the Natural Science Foundation of China (61935017,62175268)Natural Science Foundation of Guangdong Province,China (2019A1515012186)Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials (2019B121205002)Shenzhen-Hong Kong-Macao Science and Technology Innovation Project (Category C) (SGDX2020110309360100).
文摘Although multiple emissive phosphors are of great fundamental interest and practical importance,it is still challenging to achieve full-color tunable luminescence in a single-component material.Herein,we present an antimony-doped lead halide single crystal(C10NH22)2PbBr4:Sb3+with widely tunable red/green/blue/white luminescence.Extrinsic Sb3+dopants provide host another active sites to capture photo-generated excitons,thus triggering blue/red dual emission.Moreover,a reversible thermal-induced phase transition transforms blue/red emission into green/red dual emission.Both two phases exhibit intriguing excitation-wavelength dependent emission,affording a whole color gamut covering the red-green-blue(RGB)color triangle on the CIE 1931 diagram.Experimental and theoretical calculation studies reveal two emitters work independently,which paves the way for the multimode optical control and promotes the development of multifunctional luminescent materials.