Room temperature atomic layer deposited Al2O3 on CH3NH3PbI3 characterized by synchrotron-based X-ray photoelectron spectroscopy

Kot, Małgorzata; Das, Chittaranjan; Henkel, Karsten; Wojciechowski, Konrad; Snaith, Henry J.; Schmeißer, Dieter

doi:10.1016/j.nimb.2017.01.082

Cited by 15 publications

(26 citation statements)

References 30 publications

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“…The resPES characterization of the perovskite film was performed at the synchrotron radiation center BESSY‐II/HZB on the PMG2/U49‐2 beamline with the ASAM end‐station . The resPES measurement was carried out by collecting the VB spectra (2 eV–(−35) eV) at the nitrogen 1s absorption edge, by using photons from the energy range of 390 to 410 eV, and an energy step of 0.2 eV.…”

Section: Methodsmentioning

confidence: 99%

Evidence of Nitrogen Contribution to the Electronic Structure of the CH₃NH₃PbI₃ Perovskite

Kot

Wojciechowski

Snaith

et al. 2018

Chemistry A European J

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Despite fast development of hybrid perovskite solar cells, there are many fundamental questions related to the perovskite film which remain open. For example, there are contradicting theoretical reports on the role of the organic methylammonium cation (CH NH ) in the methylammonium lead triiodide (CH NH PbI ) perovskite film. From one side it is reported that the organic cation does not contribute to electronic structure of the CH NH PbI film. From the other side, valence band maximum fluctuations, dependent on the CH NH rotation, have been theoretically predicted. The resonant X-ray photoelectron spectroscopy results reported here show experimental evidence of nitrogen contribution to the CH NH PbI electronic structure. Moreover, the observed strong resonances of nitrogen with the I 5s and the Pb 5d-6s levels indicate that the CH NH PbI valence band is extended up to ≈18 eV below the Fermi energy, and therefore one should also consider these shallow core levels while modeling its electronic structure.

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Section: Methodsmentioning

confidence: 99%

Evidence of Nitrogen Contribution to the Electronic Structure of the CH₃NH₃PbI₃ Perovskite

Kot

Wojciechowski

Snaith

et al. 2018

Chemistry A European J

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“…[8,13] Figure4 shows the attenuation of the I3ds ignal versus the number of ALD cycles.I nitially,u pt oa bout 10 ALD cycles, the relative intensity of the I3ds ignal increases. [8,13] Figure4 shows the attenuation of the I3ds ignal versus the number of ALD cycles.I nitially,u pt oa bout 10 ALD cycles, the relative intensity of the I3ds ignal increases.…”

Section: Nh 3 Pbi 3 By In Situ Xpsmentioning

confidence: 99%

“…[8] It can be concludedt hat, for improving the efficiency and stabilityo fp erovskite solar cells, not only the use of an Al 2 O 3 layer,b ut also propers election of its thickness, preparation methoda nd process parameters (temperature, precursors, etc. [8] It can be concludedt hat, for improving the efficiency and stabilityo fp erovskite solar cells, not only the use of an Al 2 O 3 layer,b ut also propers election of its thickness, preparation methoda nd process parameters (temperature, precursors, etc.…”

Section: Introductionmentioning

confidence: 99%

Room‐Temperature Atomic‐Layer‐Deposited Al₂O₃ Improves the Efficiency of Perovskite Solar Cells over Time

et al. 2018

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Electrical characterisation of perovskite solar cells consisting of room-temperature atomic-layer-deposited aluminium oxide (RT-ALD-Al O ) film on top of a methyl ammonium lead triiodide (CH NH PbI ) absorber showed excellent stability of the power conversion efficiency (PCE) over a long time. Under the same environmental conditions (for 355 d), the average PCE of solar cells without the ALD layer decreased from 13.6 to 9.6 %, whereas that of solar cells containing 9 ALD cycles of depositing RT-ALD-Al O on top of CH NH PbI increased from 9.4 to 10.8 %. Spectromicroscopic investigations of the ALD/perovskite interface revealed that the maximum PCE with the ALD layer is obtained when the so-called perovskite cleaning process induced by ALD precursors is complete. The PCE enhancement over time is probably related to a self-healing process induced by the RT-ALD-Al O film. This work may provide a new direction for further improving the long-term stability and performance of perovskite solar cells.

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“…We therefore argue that the Al 2 O 3 ‐MAPI RT‐TALD samples have the less defined Trans‐AlO structure with a high number of tetrahedral sites and only few octahedral sites at their interfaces. Its high affinity to adsorb OH groups within the open Al–O network makes it an excellent candidate for an ultrathin humidity passivation layer in hybrid organic perovskite solar cells . It also provides the basis for further ALD growth with a regular Al 2 O 3 structure.…”

Section: Discussionmentioning

confidence: 99%

“…Beyond about 25 cycles, the Al2p and O1s signals stay relatively constant because the signals of the MAPI substrate approach zero and do not contribute to the total intensity. The still existing large number of tetrahedral sites results in a high affinity for OH adsorption and, hence, is responsible for perovskite protection against humidity …”

Section: Discussionmentioning

confidence: 99%

Al₂O₃‐Atomic Layer Deposited Films on CH₃NH₃PbI₃: Intrinsic Defects and Passivation Mechanisms

et al. 2019

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The initial interaction of atomic layer deposited films of Al2O3 at room temperature on CH3NH3PbI3 (MAPI) films is studied. Synchrotron radiation–based photoelectron spectroscopy is applied to analyze the initial changes in the Al‐derived features by comparing samples with different Al2O3 film thicknesses. It is found that polarons and excitons, both intrinsic defects of Al2O3, play a key role in the interface formation. The polaronic states uptake a charge from the MAPI substrate. This charge is transferred to and stabilized in the excitonic state of Al2O3 which is assigned to predominately tetrahedral coordinated Al sites. This charge transfer is initiated by vacancies present in the MAPI substrate and stabilizes a covalent bonding at the Al2O3–MAPI interface but also causes a roughening of the interface which may lead to the formation of grain boundaries. On top of the rough interface, 2D Al2O3 clusters with an increasing number of octahedrally coordinated Al—O bonds grow, and with increasing Al2O3 coverage, they introduce self‐healing of the structural defects.

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Room temperature atomic layer deposited Al2O3 on CH3NH3PbI3 characterized by synchrotron-based X-ray photoelectron spectroscopy

Cited by 15 publications

References 30 publications

Evidence of Nitrogen Contribution to the Electronic Structure of the CH₃NH₃PbI₃ Perovskite

Evidence of Nitrogen Contribution to the Electronic Structure of the CH₃NH₃PbI₃ Perovskite

Room‐Temperature Atomic‐Layer‐Deposited Al₂O₃ Improves the Efficiency of Perovskite Solar Cells over Time

Al₂O₃‐Atomic Layer Deposited Films on CH₃NH₃PbI₃: Intrinsic Defects and Passivation Mechanisms

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Room temperature atomic layer deposited Al2O3 on CH3NH3PbI3 characterized by synchrotron-based X-ray photoelectron spectroscopy

Cited by 15 publications

References 30 publications

Evidence of Nitrogen Contribution to the Electronic Structure of the CH3NH3PbI3 Perovskite

Evidence of Nitrogen Contribution to the Electronic Structure of the CH3NH3PbI3 Perovskite

Room‐Temperature Atomic‐Layer‐Deposited Al2O3 Improves the Efficiency of Perovskite Solar Cells over Time

Al2O3‐Atomic Layer Deposited Films on CH3NH3PbI3: Intrinsic Defects and Passivation Mechanisms

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Product

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Evidence of Nitrogen Contribution to the Electronic Structure of the CH₃NH₃PbI₃ Perovskite

Evidence of Nitrogen Contribution to the Electronic Structure of the CH₃NH₃PbI₃ Perovskite

Room‐Temperature Atomic‐Layer‐Deposited Al₂O₃ Improves the Efficiency of Perovskite Solar Cells over Time

Al₂O₃‐Atomic Layer Deposited Films on CH₃NH₃PbI₃: Intrinsic Defects and Passivation Mechanisms