Evaluation of the Thermoelectric Properties and Thermal Conductivity of CH3NH3PbI3–xClx Thin Films Prepared by Chemical Routes

• Published in: ACS omega Vol. 6; no. 26; pp. 16775 - 16782
• Main Authors: Karim, Al Momin Md Tanveer, Khan, M. Khalilur Rahman, Hossain, M. Sazzad
• Format: Journal Article
• Language: English
• Published: American Chemical Society 06-07-2021
• ISSN: 2470-1343
• DOI: 10.1021/acsomega.1c01294

The
thermoelectric properties and thermal conductivity of mixed-phase
CH
3
NH
3
PbI
3–
x
Cl
x
thin films have been reported as
a function of temperature, ranging from room temperature (RT) to 388
K. Thermoelectric study confirms that CH
3
NH
3
PbI
3–
x
Cl
x
is a p-type material and the charge carrier transport in CH
3
NH
3
PbI
3–
x
Cl
x
is governed by polarons and the thermal scattering
process. The Peltier function and power factor are found to decrease
initially up to ∼325 K, after which they increase with increasing
temperature. The position of (
E
F
–
E
V
) of all samples drops down sharply to zero
level around 325 K. The avalanches of thermoelectric properties at
∼325 K indicate the existence of tetragonal–cubic phase
transition in CH
3
NH
3
PbI
3–
x
Cl
x
. The calculated thermal
conductivity is very low, as desired for thermoelectric materials,
due to strong anharmonic interactions. Both the figure of merit (ZT)
and device efficiency increase with increasing temperature. However,
ZT remains small with temperature. Despite the limitations on the
operating temperature range due to phase complexity and small ZT,
CH
3
NH
3
PbI
3–
x
Cl
x
exhibits reasonable thermoelectric
power and low thermal conductivity. This signifies the possibility
of CH
3
NH
3
PbI
3–
x
Cl
x
as a prospective thermoelectric
material.