Surface Passivation Suppresses Local Ion Motion in Halide Perovskites

Pothoof, Justin; Westbrook, Robert J. E.; Giridharagopal, Rajiv; Breshears, Madeleine; Ginger, David S.

doi:10.1021/acs.jpclett.3c01089

Cited by 10 publications

(6 citation statements)

References 46 publications

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“…Our assignment of faster (and more heterogeneous) recombination at the surface is consistent with the effects of surface passivation treatments. Figure b shows time-resolved PL decays for a FA 0.83 Cs 0.17 Pb(I 0.75 Br 0.25 ) 3 perovskite film prepared in parallel with that in Figure a, but passivated with 3-aminopropyltrimethoxysilane (APTMS), a Lewis base that we have shown reduces the surface recombination velocity of many halide perovskite formulations. ,− As expected, Figure b shows that both TRPL decays exhibit a longer ⟨τ⟩ and larger β values compared to those from the unpassivated sample. In addition, the longest average lifetime and largest β value comes from the APTMS sample excited at 640 nm (⟨τ⟩ ≥ 451 ns, β = 0.67, Table ) where the sensitivity to surface recombination is mitigated by exciting farther into the bulk.…”

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confidence: 88%

Interpreting Halide Perovskite Semiconductor Photoluminescence Kinetics

Taddei,

Jariwala,

Westbrook

et al. 2024

ACS Energy Lett.

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Drawing from both experimental data and simulation, we highlight best practices for fitting time-resolved photoluminescence (TRPL) decays of halide perovskite semiconductors, which are now widely studied for applications in photovoltaics and light-emitting diodes (LEDs). First, at low excitation intensities, high-quality perovskites often show pseudo-first-order kinetics, consistent with classic minority carrier lifetimes. Second, multiexponential decays, frequently observed at low excitation intensities, often have significant contributions from spatial heterogeneity. We recommend fitting such decays with stretched exponentials, where the stretching factor (β) can be used to characterize the heterogeneity of the local lifetime distribution. Third, PL decay kinetics can depend on the excitation wavelength. We discuss how penetration depth, carrier diffusion, and surface recombination affect measurements and make recommendations for choosing experimental parameters suited to the question at hand. Accounting for these factors will provide a more reliable and physical interpretation of carrier recombination and better understanding of nonradiative losses in perovskite semiconductors.

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confidence: 88%

Interpreting Halide Perovskite Semiconductor Photoluminescence Kinetics

Taddei,

Jariwala,

Westbrook

et al. 2024

ACS Energy Lett.

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“…The treatments do not necessarily lead to a single molecular monolayer, and thicker cross-linked films of (hydrated) silicon oxide can form. When treating the perovskite films with amino-silane molecules, such as APTMS, both the silane units and the amine units may interact with the perovskite surface and each other, hence influencing their growth ( 18 , 19 ).…”

Section: Impacts Of Amino-silane Molecules On Metal-halide Perovskitesmentioning

confidence: 99%

Bandgap-universal passivation enables stable perovskite solar cells with low photovoltage loss

Lin,

Vikram,

Yang

et al. 2024

Science

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The efficiency and longevity of metal-halide perovskite solar cells are typically dictated by nonradiative defect-mediated charge recombination. In this work, we demonstrate a vapor-based amino-silane passivation that reduces photovoltage deficits to around 100 millivolts (>90% of the thermodynamic limit) in perovskite solar cells of bandgaps between 1.6 and 1.8 electron volts, which is crucial for tandem applications. A primary-, secondary-, or tertiary-amino–silane alone negatively or barely affected perovskite crystallinity and charge transport, but amino-silanes that incorporate primary and secondary amines yield up to a 60-fold increase in photoluminescence quantum yield and preserve long-range conduction. Amino-silane–treated devices retained 95% power conversion efficiency for more than 1500 hours under full-spectrum sunlight at 85°C and open-circuit conditions in ambient air with a relative humidity of 50 to 60%.

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“…Strategies for improving the PCE of perovskite solar cells based on PEA 0.2 FA 0.8 SnI 3 have focused on mitigating the formation of V sn , usually by incorporating excess Sn 2+ ions in the form of SnF 2 and imposing a higher V sn formation energy with 2D layer functionalization. − Given that the V OC is directly linked to the PLQY, ensemble steady-state and transient PL spectroscopy techniques are useful tools to assess performance. ,− Aside from ensemble photoluminescence (PL) behavior, microscale photoluminescence heterogeneity has provided important insights in both traditional III–IV semiconductor photovoltaics and Pb perovskites ,− but remains less used for Sn perovskites.…”

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confidence: 99%

Local Background Hole Density Drives Nonradiative Recombination in Tin Halide Perovskites

Westbrook,

Taddei,

Giridharagopal

et al. 2024

ACS Energy Lett.

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We use multimodal microscopy to study carrier recombination in semiconducting tin halide perovskite films based on PEA 0.2 FA 0.8 SnI 3 (PEA = phenethylammonium; FA = formamidinium). We use the observation of pseudo-firstorder photoluminescence (PL) decay kinetics to establish a method for quantifying the hole dopant level and nonradiative recombination rate constant. We find that untreated PEA 0.2 FA 0.8 SnI 3 films exhibit large hole doping concentrations of p 0 ≈ 10 19 cm −3 , which is reduced to p 0 ≈ 10 16 cm −3 after SnF 2 treatment. While it is well-known that the radiative recombination rates are increased with p 0 , we reveal that the nonradiative rate is also increased. We find that p-type regions in untreated PEA 0.2 FA 0.8 SnI 3 films are centers for nonradiative recombination, which are diminished in films with p 0 ≈ 10 16 cm −3 . We discover significant PL heterogeneity even in PEA 0.2 FA 0.8 SnI 3 films with moderate dopant levels, suggesting that new strategies to eliminate deleterious defects in PEA 0.2 FA 0.8 SnI 3 must be developed.

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Surface Passivation Suppresses Local Ion Motion in Halide Perovskites

Cited by 10 publications

References 46 publications

Interpreting Halide Perovskite Semiconductor Photoluminescence Kinetics

Interpreting Halide Perovskite Semiconductor Photoluminescence Kinetics

Bandgap-universal passivation enables stable perovskite solar cells with low photovoltage loss

Local Background Hole Density Drives Nonradiative Recombination in Tin Halide Perovskites

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