Fast non-ambipolar diffusion of charge carriers and the impact of traps and hot carriers on it in CsMAFA perovskite and GaAs
Pasanen, Hannu P. ; Liu, Maning LU
; Kahle, Hermann
; Vivo, Paola
and Tkachenko, Nikolai V.
(2021)
In Materials Advances
2(20).
p.6613-6619
- Abstract
We performed a comprehensive study of the charge carrier diffusion in the CsMAFA perovskite, one of the state-of-the-art perovskites for photovoltaic applications, starting from the diffusion of hot carriers to the eventual trapping at the surfaces and grain boundaries. We discovered evidence of non-ambipolar diffusion by using ultrafast transient reflectance spectroscopy: by comparing the transient reflectance signals of perovskite samples to a GaAs reference sample, we saw that the electrons diffused at their maximum mobility without being hindered by the slower holes. These findings dispute the common assumption of ambipolar diffusion in these materials. Then, after a few tens of picoseconds, the diffusion decelerated from 1.6 cm2... (More)
We performed a comprehensive study of the charge carrier diffusion in the CsMAFA perovskite, one of the state-of-the-art perovskites for photovoltaic applications, starting from the diffusion of hot carriers to the eventual trapping at the surfaces and grain boundaries. We discovered evidence of non-ambipolar diffusion by using ultrafast transient reflectance spectroscopy: by comparing the transient reflectance signals of perovskite samples to a GaAs reference sample, we saw that the electrons diffused at their maximum mobility without being hindered by the slower holes. These findings dispute the common assumption of ambipolar diffusion in these materials. Then, after a few tens of picoseconds, the diffusion decelerated from 1.6 cm2 s-1 to 0.2 cm2 s-1 due to traps and grain boundaries. The hot-carrier dynamics of perovskites have also garnered great interest thanks to their reported quasi-ballistic mobility and the slow cooling caused by the hot-phonon bottleneck. However, our findings dispute the ultrafast diffusion and provide an alternative explanation for the prolonged cooling. Based on our analysis, we recommend paying great attention to the carrier distribution when conducting hot-carrier studies.
(Less)
- author
- Pasanen, Hannu P.
; Liu, Maning
LU
; Kahle, Hermann
; Vivo, Paola
and Tkachenko, Nikolai V.
- publishing date
- 2021-10-21
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Materials Advances
- volume
- 2
- issue
- 20
- pages
- 7 pages
- publisher
- Royal Society of Chemistry
- external identifiers
-
- scopus:85117686370
- ISSN
- 2633-5409
- DOI
- 10.1039/d1ma00650a
- language
- English
- LU publication?
- no
- id
- 3ed13e31-8e0a-4fa3-aad8-1b76e22f9717
- date added to LUP
- 2023-08-24 12:21:44
- date last changed
- 2023-08-25 13:13:32
@article{3ed13e31-8e0a-4fa3-aad8-1b76e22f9717,
abstract = {{<p>We performed a comprehensive study of the charge carrier diffusion in the CsMAFA perovskite, one of the state-of-the-art perovskites for photovoltaic applications, starting from the diffusion of hot carriers to the eventual trapping at the surfaces and grain boundaries. We discovered evidence of non-ambipolar diffusion by using ultrafast transient reflectance spectroscopy: by comparing the transient reflectance signals of perovskite samples to a GaAs reference sample, we saw that the electrons diffused at their maximum mobility without being hindered by the slower holes. These findings dispute the common assumption of ambipolar diffusion in these materials. Then, after a few tens of picoseconds, the diffusion decelerated from 1.6 cm2 s-1 to 0.2 cm2 s-1 due to traps and grain boundaries. The hot-carrier dynamics of perovskites have also garnered great interest thanks to their reported quasi-ballistic mobility and the slow cooling caused by the hot-phonon bottleneck. However, our findings dispute the ultrafast diffusion and provide an alternative explanation for the prolonged cooling. Based on our analysis, we recommend paying great attention to the carrier distribution when conducting hot-carrier studies.</p>}},
author = {{Pasanen, Hannu P. and Liu, Maning and Kahle, Hermann and Vivo, Paola and Tkachenko, Nikolai V.}},
issn = {{2633-5409}},
language = {{eng}},
month = {{10}},
number = {{20}},
pages = {{6613--6619}},
publisher = {{Royal Society of Chemistry}},
series = {{Materials Advances}},
title = {{Fast non-ambipolar diffusion of charge carriers and the impact of traps and hot carriers on it in CsMAFA perovskite and GaAs}},
url = {{http://dx.doi.org/10.1039/d1ma00650a}},
doi = {{10.1039/d1ma00650a}},
volume = {{2}},
year = {{2021}},
}