Tailored Local Bandgap Modulation as a Strategy to Maximize Luminescence Yields in Mixed‐Halide Perovskites

Feldmann, Sascha; Neumann, Timo; Ciesielski, Richard; Friend, Richard H.; Hartschuh, Achim; Deschler, Felix

doi:10.1002/adom.202100635

Cited by 6 publications

(13 citation statements)

References 44 publications

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“…[ 5 ] Photoluminescence (PL) spectroscopy is an ubiquitous tool used to study material properties of perovskites, such as bandgap, electronic defects, local disorder, phase distribution, and dynamic effects like photo‐induced halide segregation and material degradation. [ 6–9 ] For instance, in multijunction‐compatible mixed‐halide perovskite compositions, the photoluminescence signature has been used to estimate the intrinsic phase segregation between different halide‐rich phases and accordingly evaluate passivation strategies to suppress such effects. [ 10 ] The photoluminescence lineshape and quantum yield (PLQY), often in combination with microscopy tools, have also been used as a proxy for material quality and extended to correlate the radiative yield to the quasi‐Fermi level splitting (QFLS).…”

Section: Introductionmentioning

confidence: 99%

“…[5] Photoluminescence (PL) spectroscopy is an ubiquitous tool used to study material properties of perovskites, such as bandgap, electronic defects, local disorder, phase distribution, and dynamic effects like photo-induced halide segregation and material degradation. [6][7][8][9] For instance, in multijunction-compatible mixed-halide perovskite compositions, the photoluminescence Mixed-halide perovskite films containing formamidinium (FA), methylammonium (MA), and cesium cations (Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 , henceforth referred to as 3C-PVK-17) were deposited by solution processing using an antisolvent-based processing route (see Experimental Section for details). [23] By diluting the perovskite precursor solution, films with different thicknesses ranging from ≈120 to ≈525 nm could be prepared.…”

Section: Introductionmentioning

confidence: 99%

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The Intrinsic Photoluminescence Spectrum of Perovskite Films

Pol

Datta

Wienk

et al. 2022

Advanced Optical Materials

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Photoluminescence spectroscopy is a simple and powerful characterization technique to determine material properties and dynamic effects in metal–halide perovskite optoelectronic systems. However, self‐absorption and thin film cavity effects, amplified due to their high refractive indices, can have a significant impact on spectral lineshapes, affecting the inferences drawn from such characterization. In this work, key variables extrinsic to the perovskite material influencing the photoluminescence spectrum of perovskite thin films are identified and an optical model to account for these factors is proposed. The model is used to extract the intrinsic spectrum of a film using complex refractive indices and film thickness as input variables. Lastly, the use of the model is extended to multilayer systems to demonstrate its applicability to complex device‐relevant stacks.

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Section: Introductionmentioning

confidence: 99%

“…[5] Photoluminescence (PL) spectroscopy is an ubiquitous tool used to study material properties of perovskites, such as bandgap, electronic defects, local disorder, phase distribution, and dynamic effects like photo-induced halide segregation and material degradation. [6][7][8][9] For instance, in multijunction-compatible mixed-halide perovskite compositions, the photoluminescence Mixed-halide perovskite films containing formamidinium (FA), methylammonium (MA), and cesium cations (Cs 0.05 (FA 0.83 MA 0.17 ) 0.95 Pb(I 0.83 Br 0.17 ) 3 , henceforth referred to as 3C-PVK-17) were deposited by solution processing using an antisolvent-based processing route (see Experimental Section for details). [23] By diluting the perovskite precursor solution, films with different thicknesses ranging from ≈120 to ≈525 nm could be prepared.…”

Section: Introductionmentioning

confidence: 99%

The Intrinsic Photoluminescence Spectrum of Perovskite Films

Pol

Datta

Wienk

et al. 2022

Advanced Optical Materials

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“…The work from Feldmann et al [9,10] reports on steady state photoluminescence (PL) and transient PL as well as transient absorption spectroscopy of a wide range of lead-halide perovskite absorber layers that are well suited for photovoltaics. The curious result of the study was that with the exception of the indeed quite intrinsic MAPI recipe also used in refs.…”

Section: Introductionmentioning

confidence: 99%

“…Here, we attempt to provide a theoretical basis for the findings of Feldmann et al [9,10] and develop models to perform a critical assessment of the role of doping on PL quantum yield and photovoltaic device performance. One of the conclusions of Feldmann and colleagues was that the apparent doping originated from lateral bandgap fluctuations that would cause local asymmetries between the concentrations of electrons and holes and that this level of disorder was promoting the observed performance gains.…”

Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Effect of Doping, Photodoping, and Bandgap Variation on the Performance of Perovskite Solar Cells

Das

Aguilera

Rau

et al. 2022

Advanced Optical Materials

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The most peculiar property, however, is an excellent luminescence quantum efficiency [4][5][6][7][8][9][10] that substantially exceeds that of solution processed polycrystalline films made of other material families. It is this last property that has started extensive investigations into the defect tolerance [11][12][13][14][15] of the material class and has enabled highly efficient light emitting diodes as well as solar cells with open-circuit voltages [7,[16][17][18] that so closely approach the radiative limit that they are only overcome by monocrystalline GaAs solar cells. [19] Halide perovskite devices so far have been made by employing a large library of contact materials [20][21][22][23][24] borrowed from organic solar cells, organic LEDs and dyesensitized solar cells. The key concept of device making is based on the idea that the actual light absorbing or emitting layer is fairly intrinsic and that electron and hole injection or extraction has to be ensured by contacts with suitable work functions, electron affinities and ionization potentials. [25] The classical approach of doping the active layer as done in Si, III-Vs or other inorganic semiconductors has so far only rarely been pursued and currently there is no evidence that a functional perovskite-based pn-junction [26] solar cell or LED can be made using the classical approach. Nevertheless, unintentional doping via shallow intrinsic point defects is an important topic of research, [27] triggered to a large degree by the evidence for mobile ionic charges [28,29] that lead to reversible transient effects and features like the JV curve hysteresis. [29][30][31][32] Mobile ions may appear in Frenkel pairs (i.e., for each positive ion there would be a negative ion) without actually doping the semiconductor by creating an excess of one type of charge. Therefore, it is not entirely obvious whether halide perovskites should be considered as doped semiconductors. Given the typical thicknesses and permittivities, a halide perovskite solar cell would be considered doped from doping densities of roughly >10 16 cm -3 as found in ref [32]. There is clear evidence in the most frequently studied composition methylammonium lead-iodide (MAPI) that the material behaves like an intrinsic semiconductor [33] with extremely low bulk charge densities (<10 12 cm -3 ) measured in thick crystals. [2] Furthermore, in transient photoluminescence of thin films of MAPI, [8] the signature of quadratic radiative recombination has been observed [8] down to (low) charge densities of 10 14 cm -3 , suggesting doping densities that must be even lower. There are a variety of Mott-Schottky Most traditional semiconductor materials are based on the control of doping densities to create junctions and thereby functional and efficient electronic and optoelectronic devices. The technology development for halide perovskites had initially only rarely made use of the concept of electronic doping of the perovskite layer and instead employed a variety of different contact materials to create function...

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Device Structures of Perovskite Solar Cells: A Critical Review

Deepika

Singh

Verma³

et al. 2023

Physica Status Solidi (a)

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In recent years, perovskite solar cells (PSCs) have been in huge demand because of their ease of production, low cost, flexibility, long diffusion length, lightweight, and higher performance than their counterparts. The PSCs have demonstrated remarkable progress with power conversion efficiency (PCE) up to 25.7% using FAPbI3 as an active layer component. However, lower PCE and device stability restrict PSCs' commercial viability. Further, the photocurrents in PSCs are close to the maximum Shockley–Queisser (SQ) limit. The focus now is on enhancing the open‐circuit voltage and fill factor through modifying charge‐selective contacts, the morphology of perovskite material, and interface modification. The large grain size, uniformity, and coverage area distinguish the crucial factors affecting the PCE of PSCs. Long‐term device stability and degradation mechanisms have also shown significant dependence on the device structure. Therefore, the tailoring of the device structure continues to play a crucial role in the device's performance and stability. In this review, the illustration of the structural development of perovskite solar cells, including advanced interfacial layers and their associated parameters, is discussed in detail. In addition, the challenges that hinder the PSCs' performance are also discussed.

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Tailored Local Bandgap Modulation as a Strategy to Maximize Luminescence Yields in Mixed‐Halide Perovskites

Cited by 6 publications

References 44 publications

The Intrinsic Photoluminescence Spectrum of Perovskite Films

The Intrinsic Photoluminescence Spectrum of Perovskite Films

Effect of Doping, Photodoping, and Bandgap Variation on the Performance of Perovskite Solar Cells

Device Structures of Perovskite Solar Cells: A Critical Review

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