TY - JOUR

T1 - Straightforward Determination of the Average Electron-Hole Distance in Charge-Transfer State Organic Photovoltaic Donor/Acceptor Composites from Out-of-Phase Electron Spin Echo Data

AU - Matveeva, Anna G.

AU - Syryamina, Victoria N.

AU - Nekrasov, Vyacheslav M.

AU - Lukina, Ekaterina A.

AU - Molchanov, Ivan A.

AU - Sysoev, Vitalii I.

AU - Kulik, Leonid V.

N1 - This work was supported by RSF grant No. 24-23-00484.

PY - 2025/1/25

Y1 - 2025/1/25

N2 - Photoinduced charge separation at donor–acceptor composites (active layer material of organic solar cells) is an important step of photoelectric energy conversion. It results in the formation of the interfacial charge-transfer state (CTS), which is a Coulombically bound electron-hole pair. We developed the mathematical procedure of direct quantification of the electron-hole distance on the basis of time-domain pulse electron paramagnetic resonance data, obtained in an electron spin echo (ESE) experiment. For an ensemble of CTSs characterized by a distribution of electron-hole distances, this procedure derives the average electron-hole distance without numerical simulation of the experimental data, which is a superposition of the oscillating functions, corresponding to CTSs with a certain electron-hole distance. This procedure was tested on model distance distributions, yielding very accurate results. The data for highly efficient organic photovoltaic composite PM6/Y6 were also analyzed; the average electron-hole distance within the CTS and its dependence on temperature were determined. This procedure can be useful for tracing small changes in CTS structure during optimization of the donor–acceptor composite morphology, which is tightly related to the photovoltaic efficiency of the composite.

AB - Photoinduced charge separation at donor–acceptor composites (active layer material of organic solar cells) is an important step of photoelectric energy conversion. It results in the formation of the interfacial charge-transfer state (CTS), which is a Coulombically bound electron-hole pair. We developed the mathematical procedure of direct quantification of the electron-hole distance on the basis of time-domain pulse electron paramagnetic resonance data, obtained in an electron spin echo (ESE) experiment. For an ensemble of CTSs characterized by a distribution of electron-hole distances, this procedure derives the average electron-hole distance without numerical simulation of the experimental data, which is a superposition of the oscillating functions, corresponding to CTSs with a certain electron-hole distance. This procedure was tested on model distance distributions, yielding very accurate results. The data for highly efficient organic photovoltaic composite PM6/Y6 were also analyzed; the average electron-hole distance within the CTS and its dependence on temperature were determined. This procedure can be useful for tracing small changes in CTS structure during optimization of the donor–acceptor composite morphology, which is tightly related to the photovoltaic efficiency of the composite.

KW - EPR spectroscopy

KW - charge generation

KW - electron spin echo

KW - magnetic dipolar interaction

KW - numerical modeling

KW - organic photovoltaics

UR - https://www.mendeley.com/catalogue/c56b41d3-b186-3f56-991a-c98c9e3be43e/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85218677936&origin=inward&txGid=c4109150056745275a50b5491e8c033f

U2 - 10.3390/jcs9020051

DO - 10.3390/jcs9020051

M3 - Article

VL - 9

JO - Journal of Composites Science

JF - Journal of Composites Science

SN - 2504-477X

IS - 2

M1 - 51

ER -