Traps in the spotlight: How traps affect the charge carrier dynamics in Cs2AgBiBr6 perovskite

Valentina M. Caselli; Jos Thieme; Huygen J. Jöbsis; Sohan A. Phadke; Jiashang Zhao; Eline M. Hutter; Tom J. Savenije

doi:10.1016/j.xcrp.2022.101055

Traps in the spotlight: How traps affect the charge carrier dynamics in Cs₂AgBiBr₆ perovskite

Valentina M. Caselli
, Jos Thieme
, Huygen J. Jöbsis
, Sohan A. Phadke
, Jiashang Zhao
, Eline M. Hutter
, Tom J. Savenije^*

^*Corresponding author for this work

Delft University of Technology

Research output: Contribution to journal › Article › Academic › peer-review

Abstract

Suitable optoelectronic properties of lead halide perovskites make these materials interesting semiconductors for many applications. Toxic lead can be substituted by combining monovalent and trivalent cations, such as in Cs₂AgBiBr₆. However, efficiencies of Cs₂AgBiBr₆-based photovoltaics are still modest. To elucidate the loss mechanisms, in this report, we investigate charge dynamics in Cs₂AgBiBr₆ films by double-pulse excitation time-resolved microwave conductivity (DPE-TRMC). By exciting the sample with two laser pulses with identical wavelengths, we found a clear photoconductance enhancement induced by the second pulse even 30 μs after the first laser pulse. Modeling the DPE-TRMC results, complemented by photoluminescence and transient absorption, we reveal the presence of deep emissive electron traps, while shallow hole trapping is responsible for the long-lived transient absorption signals. These long-lived carriers offer interesting possibilities for X-ray detectors or photocatalysis. The DPE-TRMC methodology offers unique insight into the times involved in charge trapping and depopulation in Cs₂AgBiBr₆.

Original language	English
Article number	101055
Pages (from-to)	1-16
Number of pages	16
Journal	Cell Reports Physical Science
Volume	3
Issue number	10
DOIs	https://doi.org/10.1016/j.xcrp.2022.101055
Publication status	Published - 19 Oct 2022

Bibliographical note

Funding Information:
V.M.C. and T.J.S. acknowledge funding from the Dutch Research Council (NWO), grant no. 739.017.004. H.J.J. and E.M.H. acknowledge funding from the Dutch Research Council (NWO) under grant no. VI.Veni.192.034. H.J.J. and E.M.H. are supported further by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC). V.M.C. prepared the samples following the procedure developed in collaboration with S.A.P. Sample characterization (absorption, PL, X-ray diffraction [XRD], SEM, DPE-TRMC, and TRPL) and data analysis have been performed by V.M.C. under the supervision of T.J.S. TA measurements have been performed by H.J.J. supervised by E.M.H. The manuscript has been written by V.M.C. and T.J.S. with the contributions of E.M.H. and H.J.J. The authors declare no competing interests.

Funding Information:
V.M.C. and T.J.S. acknowledge funding from the Dutch Research Council ( NWO ), grant no. 739.017.004 . H.J.J. and E.M.H. acknowledge funding from the Dutch Research Council (NWO) under grant no. VI.Veni.192.034. H.J.J. and E.M.H. are supported further by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC).

Publisher Copyright:
© 2022 The Author(s)

Funding

V.M.C. and T.J.S. acknowledge funding from the Dutch Research Council (NWO), grant no. 739.017.004. H.J.J. and E.M.H. acknowledge funding from the Dutch Research Council (NWO) under grant no. VI.Veni.192.034. H.J.J. and E.M.H. are supported further by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC). V.M.C. prepared the samples following the procedure developed in collaboration with S.A.P. Sample characterization (absorption, PL, X-ray diffraction [XRD], SEM, DPE-TRMC, and TRPL) and data analysis have been performed by V.M.C. under the supervision of T.J.S. TA measurements have been performed by H.J.J. supervised by E.M.H. The manuscript has been written by V.M.C. and T.J.S. with the contributions of E.M.H. and H.J.J. The authors declare no competing interests. V.M.C. and T.J.S. acknowledge funding from the Dutch Research Council ( NWO ), grant no. 739.017.004 . H.J.J. and E.M.H. acknowledge funding from the Dutch Research Council (NWO) under grant no. VI.Veni.192.034. H.J.J. and E.M.H. are supported further by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC).

Keywords

charge carrier dynamics
double-pulse excitation
excitons
lead-free perovskites
photoluminescence
thin film
time-resolved microwave conductance
transient absorption
trap states

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Cite this

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title = "Traps in the spotlight: How traps affect the charge carrier dynamics in Cs2AgBiBr6 perovskite",

abstract = "Suitable optoelectronic properties of lead halide perovskites make these materials interesting semiconductors for many applications. Toxic lead can be substituted by combining monovalent and trivalent cations, such as in Cs2AgBiBr6. However, efficiencies of Cs2AgBiBr6-based photovoltaics are still modest. To elucidate the loss mechanisms, in this report, we investigate charge dynamics in Cs2AgBiBr6 films by double-pulse excitation time-resolved microwave conductivity (DPE-TRMC). By exciting the sample with two laser pulses with identical wavelengths, we found a clear photoconductance enhancement induced by the second pulse even 30 μs after the first laser pulse. Modeling the DPE-TRMC results, complemented by photoluminescence and transient absorption, we reveal the presence of deep emissive electron traps, while shallow hole trapping is responsible for the long-lived transient absorption signals. These long-lived carriers offer interesting possibilities for X-ray detectors or photocatalysis. The DPE-TRMC methodology offers unique insight into the times involved in charge trapping and depopulation in Cs2AgBiBr6.",

keywords = "charge carrier dynamics, double-pulse excitation, excitons, lead-free perovskites, photoluminescence, thin film, time-resolved microwave conductance, transient absorption, trap states",

author = "Caselli, \{Valentina M.\} and Jos Thieme and J{\"o}bsis, \{Huygen J.\} and Phadke, \{Sohan A.\} and Jiashang Zhao and Hutter, \{Eline M.\} and Savenije, \{Tom J.\}",

note = "Funding Information: V.M.C. and T.J.S. acknowledge funding from the Dutch Research Council (NWO), grant no. 739.017.004. H.J.J. and E.M.H. acknowledge funding from the Dutch Research Council (NWO) under grant no. VI.Veni.192.034. H.J.J. and E.M.H. are supported further by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC). V.M.C. prepared the samples following the procedure developed in collaboration with S.A.P. Sample characterization (absorption, PL, X-ray diffraction [XRD], SEM, DPE-TRMC, and TRPL) and data analysis have been performed by V.M.C. under the supervision of T.J.S. TA measurements have been performed by H.J.J. supervised by E.M.H. The manuscript has been written by V.M.C. and T.J.S. with the contributions of E.M.H. and H.J.J. The authors declare no competing interests. Funding Information: V.M.C. and T.J.S. acknowledge funding from the Dutch Research Council ( NWO ), grant no. 739.017.004 . H.J.J. and E.M.H. acknowledge funding from the Dutch Research Council (NWO) under grant no. VI.Veni.192.034. H.J.J. and E.M.H. are supported further by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC). Publisher Copyright: {\textcopyright} 2022 The Author(s)",

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AU - Caselli, Valentina M.

AU - Thieme, Jos

AU - Jöbsis, Huygen J.

AU - Phadke, Sohan A.

AU - Zhao, Jiashang

AU - Hutter, Eline M.

AU - Savenije, Tom J.

N1 - Funding Information: V.M.C. and T.J.S. acknowledge funding from the Dutch Research Council (NWO), grant no. 739.017.004. H.J.J. and E.M.H. acknowledge funding from the Dutch Research Council (NWO) under grant no. VI.Veni.192.034. H.J.J. and E.M.H. are supported further by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC). V.M.C. prepared the samples following the procedure developed in collaboration with S.A.P. Sample characterization (absorption, PL, X-ray diffraction [XRD], SEM, DPE-TRMC, and TRPL) and data analysis have been performed by V.M.C. under the supervision of T.J.S. TA measurements have been performed by H.J.J. supervised by E.M.H. The manuscript has been written by V.M.C. and T.J.S. with the contributions of E.M.H. and H.J.J. The authors declare no competing interests. Funding Information: V.M.C. and T.J.S. acknowledge funding from the Dutch Research Council ( NWO ), grant no. 739.017.004 . H.J.J. and E.M.H. acknowledge funding from the Dutch Research Council (NWO) under grant no. VI.Veni.192.034. H.J.J. and E.M.H. are supported further by the Advanced Research Center Chemical Building Blocks Consortium (ARC CBBC). Publisher Copyright: © 2022 The Author(s)

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N2 - Suitable optoelectronic properties of lead halide perovskites make these materials interesting semiconductors for many applications. Toxic lead can be substituted by combining monovalent and trivalent cations, such as in Cs2AgBiBr6. However, efficiencies of Cs2AgBiBr6-based photovoltaics are still modest. To elucidate the loss mechanisms, in this report, we investigate charge dynamics in Cs2AgBiBr6 films by double-pulse excitation time-resolved microwave conductivity (DPE-TRMC). By exciting the sample with two laser pulses with identical wavelengths, we found a clear photoconductance enhancement induced by the second pulse even 30 μs after the first laser pulse. Modeling the DPE-TRMC results, complemented by photoluminescence and transient absorption, we reveal the presence of deep emissive electron traps, while shallow hole trapping is responsible for the long-lived transient absorption signals. These long-lived carriers offer interesting possibilities for X-ray detectors or photocatalysis. The DPE-TRMC methodology offers unique insight into the times involved in charge trapping and depopulation in Cs2AgBiBr6.

AB - Suitable optoelectronic properties of lead halide perovskites make these materials interesting semiconductors for many applications. Toxic lead can be substituted by combining monovalent and trivalent cations, such as in Cs2AgBiBr6. However, efficiencies of Cs2AgBiBr6-based photovoltaics are still modest. To elucidate the loss mechanisms, in this report, we investigate charge dynamics in Cs2AgBiBr6 films by double-pulse excitation time-resolved microwave conductivity (DPE-TRMC). By exciting the sample with two laser pulses with identical wavelengths, we found a clear photoconductance enhancement induced by the second pulse even 30 μs after the first laser pulse. Modeling the DPE-TRMC results, complemented by photoluminescence and transient absorption, we reveal the presence of deep emissive electron traps, while shallow hole trapping is responsible for the long-lived transient absorption signals. These long-lived carriers offer interesting possibilities for X-ray detectors or photocatalysis. The DPE-TRMC methodology offers unique insight into the times involved in charge trapping and depopulation in Cs2AgBiBr6.

KW - charge carrier dynamics

KW - double-pulse excitation

KW - excitons

KW - lead-free perovskites

KW - photoluminescence

KW - thin film

KW - time-resolved microwave conductance

KW - transient absorption

KW - trap states

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U2 - 10.1016/j.xcrp.2022.101055

DO - 10.1016/j.xcrp.2022.101055

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