Monitoring Charge Carrier Diffusion across a Perovskite Film with Transient Absorption Spectroscopy
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Monitoring Charge Carrier Diffusion across a Perovskite Film with Transient Absorption Spectroscopy. / Pasanen, Hannu P.; Vivo, Paola; Canil, Laura; Hempel, Hannes; Unold, Thomas; Abate, Antonio; Tkachenko, Nikolai V.
In: The journal of physical chemistry letters, Vol. 11, No. 2, 2020, p. 445-450.Research output: Contribution to journal › Article › Scientific › peer-review
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TY - JOUR
T1 - Monitoring Charge Carrier Diffusion across a Perovskite Film with Transient Absorption Spectroscopy
AU - Pasanen, Hannu P.
AU - Vivo, Paola
AU - Canil, Laura
AU - Hempel, Hannes
AU - Unold, Thomas
AU - Abate, Antonio
AU - Tkachenko, Nikolai V.
PY - 2020
Y1 - 2020
N2 - We have developed a new noninvasive optical method for monitoring charge carrier diffusion and mobility in semiconductor thin films in the direction perpendicular to the surface which is most relevant for devices. The method is based on standard transient absorption measurements carried out in reflectance and transmittance modes at wavelengths below the band gap where the transient response is mainly determined by the change in refractive index, which in turn depends on the distribution of photogenerated carriers across the film. This distribution is initially inhomogeneous because of absorption at the excitation wavelength and becomes uniform over time via diffusion. By modeling these phenomena we can determine the diffusion constant and respective mobility. Applying the method to a 500 nm thick triple cation FAMACs perovskite film revealed that homogeneous carrier distribution is established in few hundred picoseconds, which is consistent with mobility of 66 cm2 (V s)-1.
AB - We have developed a new noninvasive optical method for monitoring charge carrier diffusion and mobility in semiconductor thin films in the direction perpendicular to the surface which is most relevant for devices. The method is based on standard transient absorption measurements carried out in reflectance and transmittance modes at wavelengths below the band gap where the transient response is mainly determined by the change in refractive index, which in turn depends on the distribution of photogenerated carriers across the film. This distribution is initially inhomogeneous because of absorption at the excitation wavelength and becomes uniform over time via diffusion. By modeling these phenomena we can determine the diffusion constant and respective mobility. Applying the method to a 500 nm thick triple cation FAMACs perovskite film revealed that homogeneous carrier distribution is established in few hundred picoseconds, which is consistent with mobility of 66 cm2 (V s)-1.
U2 - 10.1021/acs.jpclett.9b03427
DO - 10.1021/acs.jpclett.9b03427
M3 - Article
VL - 11
SP - 445
EP - 450
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 2
ER -