TY  - JOUR
A1  - Sun, Bowen
A1  - Sandberg, Oskar
A1  - Neher, Dieter
A1  - Armin, Ardalan
A1  - Shoaee, Safa
T1  - Wave optics of differential absorption spectroscopy in thick-junction organic solar cells
T2  - Physical review applied / The American Physical Society
N2  - Differential absorption spectroscopy techniques serve as powerful techniques to study the excited species in organic solar cells. However, it has always been challenging to employ these techniques for characterizing thick-junction organic solar cells, especially when a reflective top contact is involved. In this work, we present a detailed and systematic study on how a combination of the presence of the interference effect and a nonuniform charge-distribution profile, severely manipulates experimental spectra and the decay dynamics. Furthermore, we provide a practical methodology to correct these optical artifacts in differential absorption spectroscopies. The results and the proposed correction method generally apply to all kinds of differential absorption spectroscopy techniques and various thin-film systems, such as organics, perovskites, kesterites, and two-dimensional materials. Notably, it is found that the shape of differential absorption spectra can be strongly distorted, starting from 150-nm active-layer thickness; this matches the thickness range of thick-junction organic solar cells and most perovskite solar cells and needs to be carefully considered in experiments. In addition, the decay dynamics of differential absorption spectra is found to be disturbed by optical artifacts under certain conditions. With the help of the proposed correction formalism, differential spectra and the decay dynamics can be characterized on the full device of thin-film solar cells in transmission mode and yield accurate and reliable results to provide design rules for further progress.
Y1  - 2022
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/61752
SN  - 2331-7019
VL  - 17
IS  - 5
PB  - American Physical Society
CY  - College Park
ER  -