Reduced Nonradiative Voltage Loss in Terpolymer Solar Cells
Journal article, 2020

The dissociation of hybrid local exciton and charge transfer excitons (LE-CT) in efficient bulk-heterojunction nonfullerene solar cells contributes to reduced nonradiative photovoltage loss, a mechanism that still remains unclear. Herein we studied the energetic and entropic contribution in the hybrid LE-CT exciton dissociation in devices based on a conjugated terpolymer. Compared with reference devices based on ternary blends, the terpolymer devices demonstrated a significant reduction in the nonradiative photovoltage loss, regardless of the acceptor molecule, be it fullerene or nonfullerene. Fourier transform photocurrent spectroscopy revealed a significant LE-CT character in the terpolymer-based solar cells. Temperature-dependent hole mobility and photovoltage confirm that entropic and energetic effects contribute to the efficient LE-CT dissociation. The energetic disorder value measured in the fullerene- or nonfullerene-based terpolymer devices suggested that this entropic contribution came from the terpolymer, a signature of higher disorder in copolymers with multiple aromatic groups. This gives new insight into the fundamental physics of efficient LE-CT exciton dissociation with smaller nonradiative recombination loss.


Qingzhen Bian

Linköping University

Birhan Alkadir Abdulahi

Addis Ababa University

Wollo University

Chalmers, Chemistry and Chemical Engineering

Zewdneh Genene

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

Ergang Wang

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry

W. Mammo

Addis Ababa University

O.W. Inganäs

Linköping University

Journal of Physical Chemistry Letters

1948-7185 (eISSN)

Vol. 11 10 3796-3802

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Other Chemistry Topics

Condensed Matter Physics





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8/4/2020 1