Role of microstructure in the electron–hole interaction of hybrid lead halide perovskites

Grancini, Giulia; Kandada, Ajay Ram Srimath; Frost, Jarvist M.; Barker, Alex J.; Bastiani, Michele De; Gandini, Marina; Marras, Sergio; Lanzani, Guglielmo; Walsh, Aron; Petrozza, Annamaria

doi:10.1038/nphoton.2015.151

Cited by 234 publications

(317 citation statements)

References 40 publications

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“…As recently pointed out, in fact, the fabrication procedures strongly infl uence perovskite behavior, impacting on the nature and dynamics of the photophysical mechanisms characterizing each sample. [ 41 ] The diffi culty to control solution deposition is leading to large fi lm inhomogeneity, to disordered crystals growth (as evidenced by our XRD measurements), and to external agent fi lm inclusion, such as unreacted perovskite components or solvent molecules. All these effects could detrimentally affect the radiative deactivation of the material excited states.…”

Section: Wileyonlinelibrarycommentioning

confidence: 87%

Fully Vapor‐Deposited Heterostructured Light‐Emitting Diode Based on Organo‐Metal Halide Perovskite

Genco

Mariano

Carallo

et al. 2016

Adv Elect Materials

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Section: Wileyonlinelibrarycommentioning

confidence: 87%

Fully Vapor‐Deposited Heterostructured Light‐Emitting Diode Based on Organo‐Metal Halide Perovskite

Genco

Mariano

Carallo

et al. 2016

Adv Elect Materials

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“…The high density of surface traps is attributed to arise from dangling bonds and uncoordinated atoms (e.g., Pb 2+ , etc.). [38] The surface of the crystal resembles polycrystalline thin films having high MA + orientation disorder, [39] which could also acts as potential traps. [40] The similarities in the peak positions and PL decay lifetimes (discussed earlier) in the surface region of the SC (Figure 1a Figure S4, Supporting Information, for MAPbI 3 ) also suggest that the surface band structure of the SCs closely resembles that of the polycrystalline TFs.…”

Section: Optical Propertiesmentioning

confidence: 99%

“…Furthermore, the long range order of the organic molecule dipoles in the bulk would result in fewer traps. [39] The trap density also has a direct correlation with the diffusion lengths of the photoexcited species (free carriers or bound electron-hole pairs). Higher trap density will lead to more significant carrier/exciton capture and therefore lower mobilities and shorter diffusion lengths.…”

Section: Optical Propertiesmentioning

confidence: 99%

Discerning the Surface and Bulk Recombination Kinetics of Organic–Inorganic Halide Perovskite Single Crystals

Nguyen

et al. 2016

Advanced Energy Materials

294

336

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Organic–inorganic halide perovskite single crystals possess many outstanding properties conducive for photovoltaic and optoelectronic applications. However, a clear photophysics picture is still elusive, particularly, their surface and bulk photophysics are inexorably convoluted by the spectral absorbance, defects, coexisting photoexcited species, etc. In this work, an all‐optical study is presented that clearly distinguishes the surface kinetics from those of the bulk in the representative methylammonium‐lead bromide (MAPbBr3) and ‐lead iodide (MAPbI3) single crystals. It is found that the bulk recombination lifetime of the MAPbBr3 single crystal is shortened significantly by approximately one to two orders (i.e., from ≈34 to ≈1 ns) at the surface with a surface recombination velocity of around 6.7 × 103 cm s−1. The surface trap density is estimated to be around 6.0 × 1017 cm−3, which is two orders larger than that of the bulk (5.8 × 1015 cm−3). Correspondingly, the diffusion length of the surface excited species is ≈130–160 nm, which is considerably reduced compared to the bulk value of ≈2.6–4.3 μm. Furthermore, the surface region has a wider bandgap that possibly arises from the strong lattice deformation. The findings provide new insights into the intrinsic photophysics essential for single crystal perovskite photovoltaics and optoelectronic devices.

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“…They also show that electrostatic disorder in the film is correlated with its grain size and significantly impacts corresponding binding energies. [20] A deeper understanding of electronic properties can be obtained when the temperature dependence of the calculated parameters is considered. The temperature dependence of the bandgap energy has two contributions: the thermal lattice dilatation, which causes an increase and the electronphonon coupling, which causes a decrease of the bandgap energy with temperature.…”

Section: Absorptionmentioning

confidence: 99%

Impact of Structural Dynamics on the Optical Properties of Methylammonium Lead Iodide Perovskites

Panzer

Meier

et al. 2017

Advanced Energy Materials

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structure, [2] and changing the ratio of precursor compounds prior to the formation of the perovskite layer. [3] These approaches are based on modifying the crystallization process, for example, by controlling the composition of the precursor solution and by varying processing parameters. Such changes also led to major improvements in perovskite-based light-emitting devices within the last year. Initially, the current efficiencies were improved by optimizing the grain size to values below 100 nm, and by changing the precursor compound molar proportions. [4] More recently, efficient perovskite-based LEDs with external quantum efficiencies exceeding 10% were even obtained by expanding towards lower dimensional perovskite structures. [5] Different structures and dimensionalities resulted in altered charge-carrier dynamics affecting the radiative recombination efficiency. [5,6] By drawing strong correlations between structural properties and their electronic structure, major breakthroughs toward light-emitting devices or in photovoltaics could be achieved in very recent years. To a certain extent, this resembles the evolution in the field of organic semiconductors, where improved understanding of the interplay between morphological and electronic structure proved essential to facilitate the recent progress in organic photovoltaics, and the successful commercialisation of organic LED devices. Also, for hybrid perovskites the question of how crystal structure, shape, and grain size governs the electronic structure will remain an important topic in the future to further improve perovskite-based optoelectronic devices. Since the solution processability of hybrid perovskites enables easy tuning of material compositions, a large number of different hybrid perovskites were reported. For example, exchanging the organic cation can alter the crystal structure, shift phase transitions, as does formamidinium, or change further excited-state dynamics, as is happening with Cs or Ru. Furthermore, different halide anions change the optical and excited state properties. The optical bandgap can be changed from the UV to NIR region by replacing the halide from Cl to Br to I. Mixed-halide systems thereof even provide a way to gradually tune the respective bandgap. In fact, the recently reported, most stable and efficient perovskite solar cells (PSCs) are based on a highly optimized mixture of different anions and cations. [1,7] Nevertheless, the most investigated hybrid perovskite representative is the methylammonium lead iodide perovskite CH 3 NH 3 PbI 3 (MAPbI 3 ), which, in the meantime, has become Organolead halide perovskites have attracted a lot of attention over the recent years mostly due to their bright prospective application in photovoltaic devices. For further development, characterization of their physical properties plays a seminal role in order to gain an in-depth understanding of these mid-bandgap ionic semiconductors. Their unique optical and electronic properties are a result of their characteristic electronic stru...

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Role of microstructure in the electron–hole interaction of hybrid lead halide perovskites

Cited by 234 publications

References 40 publications

Fully Vapor‐Deposited Heterostructured Light‐Emitting Diode Based on Organo‐Metal Halide Perovskite

Fully Vapor‐Deposited Heterostructured Light‐Emitting Diode Based on Organo‐Metal Halide Perovskite

Discerning the Surface and Bulk Recombination Kinetics of Organic–Inorganic Halide Perovskite Single Crystals

Impact of Structural Dynamics on the Optical Properties of Methylammonium Lead Iodide Perovskites

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