TY - JOUR
T1 - Traps in the spotlight
T2 - How traps affect the charge carrier dynamics in Cs2AgBiBr6 perovskite
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.
PY - 2022
Y1 - 2022
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
UR - http://www.scopus.com/inward/record.url?scp=85140094473&partnerID=8YFLogxK
U2 - 10.1016/j.xcrp.2022.101055
DO - 10.1016/j.xcrp.2022.101055
M3 - Article
AN - SCOPUS:85140094473
SN - 2666-3864
VL - 3
JO - Cell Reports Physical Science
JF - Cell Reports Physical Science
IS - 10
M1 - 101055
ER -