TY - JOUR
T1 - Reversible Removal of Intermixed Shallow States by Light Soaking in Multication Mixed Halide Perovskite Films
AU - Guo, Dengyang
AU - Andaji Garmaroudi, Zahra
AU - Abdi-Jalebi, Mojtaba
AU - Stranks, Samuel D.
AU - Savenije, Tom J.
PY - 2019
Y1 - 2019
N2 - The highest reported efficiencies of metal halide perovskite (MHP) solar cells are all based on mixed perovskites, such as (FA,MA,Cs)Pb(I1-xBrx)3. Despite demonstrated structural changes induced by light soaking, it is unclear how the charge carrier dynamics are affected across this entire material family. Here, various (FA,MA,Cs)Pb(I1-xBrx)3 perovskite films are light-soaked in nitrogen, and changes in optoelectronic properties are investigated through time-resolved microwave conductivity (TRMC) and optical and structural techniques. To fit the TRMC decay kinetics obtained for pristine (FA,MA,Cs)Pb(I1-xBrx)3 for various excitation densities, additional shallow states have to be included, which are not required for describing TRMC traces of single-cation MHPs. These shallow states can, independently of x, be removed by light soaking, which leads to a reduction in the imbalance between the diffusional motion of electrons and holes. We interpret the shallow states as a result of initially well-intermixed halide distributions, which upon light soaking segregate into domains with distinct band gaps.
AB - The highest reported efficiencies of metal halide perovskite (MHP) solar cells are all based on mixed perovskites, such as (FA,MA,Cs)Pb(I1-xBrx)3. Despite demonstrated structural changes induced by light soaking, it is unclear how the charge carrier dynamics are affected across this entire material family. Here, various (FA,MA,Cs)Pb(I1-xBrx)3 perovskite films are light-soaked in nitrogen, and changes in optoelectronic properties are investigated through time-resolved microwave conductivity (TRMC) and optical and structural techniques. To fit the TRMC decay kinetics obtained for pristine (FA,MA,Cs)Pb(I1-xBrx)3 for various excitation densities, additional shallow states have to be included, which are not required for describing TRMC traces of single-cation MHPs. These shallow states can, independently of x, be removed by light soaking, which leads to a reduction in the imbalance between the diffusional motion of electrons and holes. We interpret the shallow states as a result of initially well-intermixed halide distributions, which upon light soaking segregate into domains with distinct band gaps.
UR - http://www.scopus.com/inward/record.url?scp=85073813011&partnerID=8YFLogxK
U2 - 10.1021/acsenergylett.9b01726
DO - 10.1021/acsenergylett.9b01726
M3 - Article
AN - SCOPUS:85073813011
SN - 2380-8195
VL - 4
SP - 2360
EP - 2367
JO - ACS Energy Letters
JF - ACS Energy Letters
IS - 10
ER -
