TY - JOUR
T1 - Observation of Negative Photoconductivity in Lead-Free Cs3Bi2Br9Perovskite Single Crystal
AU - Tailor, Naveen Kumar
AU - Maity, Partha
AU - Satapathi, Soumitra
N1 - KAUST Repository Item: Exported on 2021-07-27
Acknowledgements: S.S. acknowledges the ISRO Research Grant (STC-1563-PHY). N.K.T. is thankful for the UGC fellowship.
PY - 2021/7/21
Y1 - 2021/7/21
N2 - Light exposure usually causes an increase in photoconductivity in perovskite semiconductors. However, we report here light-induced negative photoconductivity, followed by slow dark self-recovery in a lead-free Cs3Bi2Br9 perovskite single crystal. Femtosecond transient reflection (fs-TR) spectroscopy studies further reveal hole self-trapping at the Vk center (Br2– dimer) in the midband states of this vacancy-ordered perovskite. Subsequently, these charged defect states (Vk) trap photogenerated charge carriers and produce an internal electrical field, which essentially opposes the externally applied field, leading to negative photoconductivity. A highly sensitive prototype photodetector was fabricated with figure of merits estimated as responsivity (6.42 mA/W), detectivity (2.51 × 1012 Jones), and current in a dark to light ratio (∼20). Our observation of this retrospective photocurrent in optically active perovskite materials can be applied for developing highly sensitive detectors.
AB - Light exposure usually causes an increase in photoconductivity in perovskite semiconductors. However, we report here light-induced negative photoconductivity, followed by slow dark self-recovery in a lead-free Cs3Bi2Br9 perovskite single crystal. Femtosecond transient reflection (fs-TR) spectroscopy studies further reveal hole self-trapping at the Vk center (Br2– dimer) in the midband states of this vacancy-ordered perovskite. Subsequently, these charged defect states (Vk) trap photogenerated charge carriers and produce an internal electrical field, which essentially opposes the externally applied field, leading to negative photoconductivity. A highly sensitive prototype photodetector was fabricated with figure of merits estimated as responsivity (6.42 mA/W), detectivity (2.51 × 1012 Jones), and current in a dark to light ratio (∼20). Our observation of this retrospective photocurrent in optically active perovskite materials can be applied for developing highly sensitive detectors.
UR - http://hdl.handle.net/10754/670287
UR - https://pubs.acs.org/doi/10.1021/acsphotonics.1c00702
U2 - 10.1021/acsphotonics.1c00702
DO - 10.1021/acsphotonics.1c00702
M3 - Article
SN - 2330-4022
JO - ACS Photonics
JF - ACS Photonics
ER -