Photonic Devices And Applications: Perovskite LED And Laser
Photonic Devices and Applications:Perovskite LED and LaserQi DongOEMDlabDepartment of Materials Science and EngineeringNorth Carolina State University
Light Emitting of PerovskitesPerovskite LEDsPerovskite lasers2
Halide Perovskite CompositionChemical formula: 𝑨𝑩𝑿𝟑A-site:methylammonium cation (𝑀𝐴' ), formamidinium cation (𝐹𝐴' ), 𝐶𝑠 'B-site:𝑃𝑏 -' , 𝑆𝑛-'X-site:𝐶𝑙1 , 𝐵𝑟 1 , 𝐼 1𝑀𝐴'𝐹𝐴'Examples: Single composition:𝑀𝐴𝑃𝑏𝐼5 , 𝐹𝐴𝑃𝑏𝐼5 , 𝐶𝑠𝑃𝑏𝐵𝑟5 Mixed composition: 𝑀𝐴𝑃𝑏𝐼6 𝐵𝑟516 , 𝑀𝐴6 𝐶𝑠716 𝐵𝑟5 Lead-free perovskite: 𝑀𝐴𝑆𝑛𝐼5 , 𝑀𝐴𝑆𝑛𝐵𝑟53
Perovskite Crystal StructureTolerance factor:𝑡 𝑟: 𝑟 2(𝑟? 𝑟 )tCrystal system 1.0Hexagonal or Tetragonal0.9 1.0Cubic0.71 0.9Orthorhombic/Rhombohedral 0.71Different structuresComposition effectCompositionCrystal system at ���𝑟5CubicTemperature effectTemperatureCrystal system of 𝑴𝑨𝑷𝒃𝑰𝟑 162 KOrthorhombic162 K 327 KTetragonal 327 KCubicQuarti et al. Energy Environ. Sci., 2016, 9, 155-163.4
Perovskite PropertiesA semiconductor with tunable band gap𝐌𝐀𝐏𝐛𝐗 𝟑Pathak et al. Chem. Sci., 2015, 6, 613–617.Pathak et al. Chem. Mater., 2015, 27, 8066 8075.5
Perovskite PropertiesDefect tolerance: Dominant intrinsic defects are mainly shallow defectsBuin et al. Nano Lett., 2014, 14, 6281 62866
Perovskite Properties Narrow Emission linewidthPLQY 90% High PLQYProtesescu et al. Nano Lett., 2015, 15, 3692 3696Long carrier diffusionlengthStranks et al. Science, 2013, 342, 341-3437
Quasi-2D Perovskite𝐵𝑋K 1L octahedronLayered structureBulky organic cationA-site cationKim et al. Small Methods, 2018, 2, 1700310.Advantages of quasi-2D perovskite:Example of bulky organic cation: Improved stability (higher formationenergy) Defect passivation by amine group(high PLQY)Phenethylammonium (PEA)n-butylammonium (BA)8
Fabrication of PerovskitePrecursor solutionAnti-solventThermal annealingPerovskitesubstrateHot plateSpin coatingPrecursor solvents:Dimethylformamide (DMF), Dimethyl sulfoxide (DMSO), N-Methyl-2-pyrrolidone (NMP)Antisolvents:Chlorobenzene (CB), Toluene, ChloroformAnti-solvent dripping is used to control crystalgrowth and morphology9
Device Structure of PeLEDConventional structureInverted TLETLITOITOAdjokatse et al. Mater. Today, 2017, 20, 413-424.10
Performance of PeLEDsRed PeLEDCao et al. Nature, 2018, 562, 249-253.Green PeLEDLin et al. Nature, 2018, 562, 245-248.11
Ion Migration in PerovskitesThe short operational lifetime of PeLED compared to OLED is mainly due to ion migration.Both Halide ion and 𝑀𝐴' are mobileEames et al. Nat. Commun., 2015, 6, 7497.Christie L.C. (2018), Perovskite photovoltaics (Chapter 6). Academic Press.12
Degradation MechanismIon migration is the main reason for device degradation𝐵𝑟 1 and 𝑀𝐴' in Al electrode by SIMSFresh perovskiteAfter degradationLee et al. ACS Appl. Mater. Interfaces, 2019, 11, 11667 11673.13
Improve Stability by PassivationPEIElectrode corrosion by 𝐵𝑟 1 migrationEDALee et al. J. Phys. Chem. Lett., 2017, 8, 1784-1792.14
Improve Stability by Ion Blocking Layer Metal oxides (ZnO and NiOx) function as ion blocking layer Stability of PeLEDs can be improvedZhuang et al. Ceram. Int., 2018, 44, 4685-4688.15
Perovskite LasersLight Amplification by Stimulated Emission of Radiation (LASER)General properties of laser: MonochromaticDirectionalCoherentHigh intensityWide applications of laser:Manufacturing, medical, data storage, communication, display, spectroscopy, military and so on.Perovskite materials can be used for semiconductor lasers.16
Fundamentals of Semiconductor onE (eV)e- �-7(UYZ[)𝐸NP𝑅7-(\]U)𝐸Ph populationCondition of population inversion (enough carrier density):𝐸NO 𝐸NP 𝐸O 𝐸P 𝐸S𝐸NO : Quasi fermi level of electron𝑅-7(UYZ[) 𝑅7-(\]U)Optical gain 0𝐸NP : Quasi fermi level of holeT. Numai, (2015), Fundamentals of semiconductor laser, Springer17
ASE of PerovskitesPumping laser: 600 nm, 150 fs,1 kHzAmplified Spontaneous Emission (ASE)No optical feedbackPumping laserMaterials: 𝑀𝐴𝑃𝑏𝐼5PL or ASEPeovskite filmXing et al. Nat. Mater., 2014, 13, 476-480.18
Distributed Feedback Laser by Perovskitem 2PerovskitePolymerm 12neffΛ mλBraggm 1: edge emission modem 2: surface emission modeSaliba et al. Adv. Mater., 2016, 28, 923-92919
Distributed Feedback Laser by PerovskitePumping laser: 532 nm, 1ns,1 kHz2Λ λBragg2neffΛ mλBraggneff 1.9 2.0Saliba et al. Adv. Mater., 2016, 28, 923-9292Λ λBraggm 220
Optical Design of OLED and Perovskite LEDXiangyu FuOEMDlabDepartment of Materials Science and EngineeringNorth Carolina State University
Typical OLED/PeLED StructureAlHTLElectron Transport Layer(ETL)EMLEmitting Layer(EML)Hole Transport Layer(HTL)eITOh e-AlETLh ITOSubstrateAir mode Light is generated in the high refractive index thin film ( 200 nm) 20 30% of all the light goes to air mode22
Optical StructureAsymmetric metal-clad waveguideReflective cathodeMetal claddingOrganic or Perovskite layerTransparent anodeSubstrateCoreCladding claddingDielectricAirR 90%Surface plasmonsR(normal) 4%Total internal reflectionAirMaterialRefractive ED/PeLED can be regarded as opticalmicrocavities which support waveguide modes andSPP modes23
SPP and Waveguide ModesSurface Plasmon Polariton (SPP) mode - - - -Metal - -𝜺𝑴Waveguide ovskiteSubstrateSubstrate𝒌𝑺𝑷𝑷 𝝎 front𝝎𝜺𝒅 𝜺𝑴𝒄 𝜺𝑴 𝜺𝒅TIR Both SPP and waveguide modes have quantizedmode dispersion relation24
Microcavity Effectndθl 2nd cos q - pθ 𝑚 2𝜋@ λ 520 nmAlRETLWavefrontR 90%2pAir Mode Substrate ModeθWavefrontndDf Constructive InterferenceEMLI0I0RHTLITOR 2%Sub(I I 0 I 0 R 2 I 0 I 0 R cos Df I 0 1 R 2 R cos DestructiveETL Thickness (nm))I integrated I 0 ò 2p 1 R 2 R cos Df dq-225
Optical Mode DistributionOLEDPerovskite LED (PeLED)100SPPMode Percentage 150200250ETL Thickness (nm)Adv. Mater. 2019, 31, 180583626
Light ExtractionSuppress TIRDiffractionCorrugationHalf-ball lensSub-anode gridsPlanar OLED/PeLEDMetalOrganic/PerovskiteITOGlassRandom ScatteringMicrolens arraysPorous substrate Roughened surface27
Soft-Imprinted ZnO Moth eye nanostructures periodicity 400 nmAdv. Mater. 2019, 31, 190151728
Spontaneously Formed Perovskite Platelets1 μm100 nmNature 562.7726 (2018): 249.29
In-plane Wavevector and Dispersion DiagramIn-plane wavevectorDispersion diagram for an OLEDMetal cathodeOrganic layer/Perovskite 𝑘 ITO𝝎Substrate ITOqorganicAir𝑐 q 𝑘 𝑐 q 𝑘 𝜔 𝑐 q 𝑘 𝜔 𝜔 𝑛Sr\UU𝑛s.u.TMTE𝑘𝜃SPPGlass𝑘 𝜃𝑘𝜔𝑘 𝑛𝑘0 sin 𝜃 𝑛 sin 𝜃𝑐𝒌 Advantage of the concept of in-plane wavevector1. It describes light traveling under a certain angle2. It is conserved at the interfaces3. We could plot dispersion diagram for an OLED/PeLED30
Simulated Mode Dispersionnsubk0k0@ 520 nmTMWTE GWGSimulated Mode DispersionS LightP LightViewing angle-90 -30 0 90 30 deSPPmoSubAirmodes2.4WGPhoton Energy (eV)2.6Mode Density (a.u.)TE WG2.22-30-20-10010In-plane wavevector k// (μm-1)2030TE WGSubSubAirSPPSPPTM WG-30-20TM WG-1001020In-plane wavevector k// (μm-1)3130
Bragg Diffraction kWG-deSPPmomodeskG2.22-30kGGrating Vector2.4WGCorrugated Layerk’WG2.6ExtractɅed WaveguidWaveguidePhoton Energy (eV)High Index MediumeTMTEBragg Diffraction-20-1001020In-plane wavevector kx (μm-1)kG 2π/Ʌ Bragg diffraction is useful in PeLEDs due to the large waveguide mode portionand narrow spectrum3230
Light Extraction with Corrugated SubstratesSPPTM WGLinear gratingSquare lattice (single crystal)AlOrganicITOTE WGHexagonal lattice(single crystal)Hexagonal lattice(poly crystal)CorrugatedSubstrate33
Mode Dispersion ComparisonPlanar OLEDOLEDdevicePolarizerOptical fiberE (eV)Rotary stageSpectrometerkx(μm-1)Corrugated OLEDTM WGE (eV) Angular EL spectra (ARES) measurementsreveal the origin of the extracted light Guides the design of devicesTE WGSPPkx(μm-1)34
CorrugatedCorrugatedOLEDOLED PerformancePerformancePlanar OLEDCorrugated OLED(with lens)EQE70Metal60Corrugated (lens) 63%ITO ( n 2.0)Glass (n 1.5)50EQE (%)Organic Layers(n 1.75)40Corrugated 33%30201000.01Planar 27%Corrugated(Single Crystal with Lens)Corrugated(Single Crystal)Planar0.11102Current Density (mA/cm )
Summary OLED/PeLEDs are microcavity devices which supportwaveguide/substrate and SPP modes PeLEDs have strong waveguide loss due to the thick EML and highrefractive index Current waveguide mode extraction in PeLEDs is mostly throughrandom scattering, but Bragg diffraction with a periodic structure couldbe more advantageous Optical characterization through angle-resolved EL measurements willgive important guidelines for optimization36
AcknowledgementDr. Franky SoDong-Hun ShinStephen AmoahLei Lei37
Sep 15, 2019 · Transparent anode Organic or Perovskite layer Reflective cathode Air OLED/PeLED can be regarded as optical microcavities which support waveguide modes and SPP modes . Planar OLED. Corrugated OLED PerformanceCorrugated OLED Performance EQE 0.01 0.1 1 10 0 10 20 30 40 50 60 70 Corrugated(Single Crystal with
21% ferropericlase, and 7% CaSiO 3 perovskite by weight. Al-bearing (Mg,Fe)SiO 3 perovskite is also the most abundant phase in a MORB composition above 26 GPa, coexisting with an SiO 2 phase, CaSiO 3 perovskite, and a Ca-ferrite-type Al phase (e.g. Hirose et al. 2005). The perovskite to post-perovskite phase transition takes place in MORB .
the economic viability of solar energy. A great contender in advancing photovoltaics are perovskite solar cells. Perovskite solar cells have increased their efficiency from 3.8% in 2009 to 22.7% in late 20172. Perovskite solar cells have the potential to achieve higher efficiencies at very low production costs.
terial in the silicon-on-insulator (SOI) fabrication process. 2 SILICON PHOTONIC LINKS A photonic link is by fi equipped with a transmit unit (Tx) and a receive unit (Rx). The link architecture based on an inte-grated photonic platform such as Silicon Photonics can be envis-aged as the ones presented in Fig. 1 [7, 10]. The Tx requires in-
Once completed this deposition, the chamber was vented with dry N2 to replace the p-HTL crucibles with those containing the starting materials for the perovskite deposition, PbI2 and CH3NH3I. The vacuum chamber was evacuated again to a pressure of 10-6 mbar, and the perovskite films were then obtained by co-deposition of the two precursors.
Fe-Doping in Double Perovskite PrBaCo 2(1-x)Fe2xO6- : . Overall, our findings underline synergetic effects of incorporating Fe into Co-based layered double perovskite in achieving a higher activity and stability during oxygen evolution reaction. . insights into changes in local electronic and geomet
SUNCAT Center for Interface Science and Catalysis Department of Chemical Engineering Stanford University Stanford, CA 94305, USA Hysteresis-Free Perovskite Solar Cells Perovskite solar cells (PSCs) have emerged as a promising next generation of solar cells, as their power conversion efficie
solar cells (PSC) are introduced from dye-sensitized solar cells (DSSCs), the presence of a perovskite capping layer as opposed to a single dye molecule (in DSSCs) changes the interactions between the various layers in perovskite solar cells. 4-tert-butylpyridine (tBP), commonly used in PSCs, is assumed to function as a charge
Artificial Intelligence Chapter 1 Chapter 1 1. Outline} What is AI?} A brief history} The state of the art Chapter 1 2. What is AI? Systems that think like humans Systems that think rationally Systems that act like humans Systems that act rationally Chapter 1 3. Acting humanly: The Turing test Turing (1950) \Computing machinery and intelligence":} \Can machines think?" ! \Can machines behave .
