Origin of long lifetime of band-edge charge carriers in organic–inorganic lead iodide perovskites
- Univ. of Virginia, Charlottesville, VA (United States). Dept. of Physics
- National Taiwan Univ., Taipei (Taiwan). Center for Condensed Matter Sceinces
- Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemical Engineering
- Cornell Univ., Ithaca, NY (United States). Cornell High Energy Synchrotron Source (CHESS)
- National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States). Center for Neutron Research
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
Long carrier lifetime is what makes hybrid organic–inorganic perovskites high-performance photovoltaic materials. Several microscopic mechanisms behind the unusually long carrier lifetime have been proposed, such as formation of large polarons, Rashba effect, ferroelectric domains, and photon recycling. Here, we show that the screening of band-edge charge carriers by rotation of organic cation molecules can be a major contribution to the prolonged carrier lifetime. Our results reveal that the band-edge carrier lifetime increases when the system enters from a phase with lower rotational entropy to another phase with higher entropy. These results imply that the recombination of the photoexcited electrons and holes is suppressed by the screening, leading to the formation of polarons and thereby extending the lifetime. Furthermore, searching for organic–inorganic perovskites with high rotational entropy over a wide range of temperature may be a key to achieve superior solar cell performance.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0016144; AC02-05CH11231
- OSTI ID:
- 1498113
- Journal Information:
- Proceedings of the National Academy of Sciences of the United States of America, Vol. 114, Issue 29; ISSN 0027-8424
- Publisher:
- National Academy of Sciences, Washington, DC (United States)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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