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Nanoscale chemical heterogeneity dominates the optoelectronic response of alloyed perovskite solar cells

Abstract

Halide perovskites perform remarkably in optoelectronic devices. However, this exceptional performance is striking given that perovskites exhibit deep charge-carrier traps and spatial compositional and structural heterogeneity, all of which should be detrimental to performance. Here, we resolve this long-standing paradox by providing a global visualization of the nanoscale chemical, structural and optoelectronic landscape in halide perovskite devices, made possible through the development of a new suite of correlative, multimodal microscopy measurements combining quantitative optical spectroscopic techniques and synchrotron nanoprobe measurements. We show that compositional disorder dominates the optoelectronic response over a weaker influence of nanoscale strain variations even of large magnitude. Nanoscale compositional gradients drive carrier funnelling onto local regions associated with low electronic disorder, drawing carrier recombination away from trap clusters associated with electronic disorder and leading to high local photoluminescence quantum efficiency. These measurements reveal a global picture of the competitive nanoscale landscape, which endows enhanced defect tolerance in devices through spatial chemical disorder that outcompetes both electronic and structural disorder.

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Fig. 1: Hyperspectral microscopy of perovskite solar cell device stacks.
Fig. 2: Correlation between optoelectronic properties in FA0.79MA0.16Cs0.05Pb(I0.83Br0.17)3 perovskite films.
Fig. 3: Spatial relationships between halide composition, structural and optoelectronic variations in FA0.79MA0.16Cs0.05Pb(I0.83Br0.17)3 perovskite films.
Fig. 4: TAM of FA0.79MA0.16Cs0.05Pb(I0.83Br0.17)3 perovskite films correlated with local chemical mapping.

Data availability

The data and code that support the findings of this study are available in the University of Cambridge Apollo repository at https://doi.org/10.17863/CAM.76854.

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Acknowledgements

K.F. acknowledges a George and Lilian Schiff Studentship, Winton Studentship, the Engineering and Physical Sciences Research Council (EPSRC) studentship, Cambridge Trust Scholarship and Robert Gardiner Scholarship. M.A. acknowledges funding from the Marie Skłodowska-Curie actions (grant agreement no. 841386) under the European Union’s Horizon 2020 research and innovation programme. S.M. and K.W.P.O. acknowledge EPSRC studentships. T.A.S.D. acknowledges a National University of Ireland Travelling Studentship. Y.-H.C. thanks the Cambridge Trust and Rank Prize fund. We acknowledge the Diamond Light Source (Didcot, Oxfordshire, UK) for providing beamtime at the I14 Hard X-ray Nanoprobe facility through proposals sp19023 and sp20420. S.D.S. acknowledges the Royal Society and Tata Group (grant no. UF150033). The work has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (HYPERION, grant agreement no. 756962; SOLARX, grant agreement no. 758826). Y.H.-C. thanks the Cambridge Trust for a studentship. We acknowledge the EPSRC (grant nos. EP/R023980/1, EP/M006360/1) and the Winton Programme for the Physics of Sustainability for funding. A.J.W. and K.M.D. acknowledge that this work was supported by the Femtosecond Spectroscopy Unit of the Okinawa Institute of Science and Technology Graduate University and JSPS Kakenhi grant no. JP19K05637. We acknowledge the support for this work from the Imaging Section and Engineering Support Section of the Okinawa Institute of Science and Technology Graduate University. K.F. acknowledges N-11 for fruitful discussion. K.F., M.A., S.M. and T.A.S.D. acknowledge HQS.

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K.F., M.A. and S.D.S conceived the project. K.F. and M.A. developed the quantitative optical microscopy and performed the measurements, which were analysed by K.F. K.F., M.A., S.M., T.A.S.D., K.W.P.O., J.E.P. and P.D.Q. performed the synchrotron nXRF and nXRD experiments that were analysed by K.F and T.A.S.D. S.M. and J.S. performed the TAM measurements and analysed the data supervised by A.R. K.F., M.A. and S.M. performed the correlative analysis of the multimodal data. Y.-H.C. fabricated the thin film and device perovskite samples and performed bulk XRD experiments. A.J.W. performed the PEEM measurements supervised by K.M.D. S.D.S. supervised and funded the work. K.F. and M.A. wrote the draft of the manuscript with the input of S.D.S. All authors contributed to the revision of the final paper.

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Correspondence to Miguel Anaya or Samuel D. Stranks.

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S.D.S. is a cofounder of Swift Solar.

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Peer review information Nature Nanotechnology thanks Mike McGehee and Shuji Ye for their contribution to the peer review of this work.

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Frohna, K., Anaya, M., Macpherson, S. et al. Nanoscale chemical heterogeneity dominates the optoelectronic response of alloyed perovskite solar cells. Nat. Nanotechnol. 17, 190–196 (2022). https://doi.org/10.1038/s41565-021-01019-7

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