TY - JOUR

T1 - Fast Recombination of Charge-Transfer State in Organic Photovoltaic Composite of P3HT and Semiconducting Carbon Nanotubes Is the Reason for Its Poor Photovoltaic Performance

AU - Uvarov, Mikhail N

AU - Kobeleva, Elena S

AU - Degtyarenko, Konstantin M

AU - Zinovyev, Vladimir A

AU - Popov, Alexander A

AU - Mostovich, Evgeny A

AU - Kulik, Leonid V

N1 - Funding: This research was funded by the state assignment of V. V. Voevodsky Institute of Chemical Kinetics and Combustion of the Siberian Branch of the Russian Academy of Sciences, grant number No. AAAA-A21-121011390038-1. The APC was funded by V. V. Voevodsky Institute of Chemical Kinetics and Combustion of the Siberian Branch of the Russian Academy of Sciences.

PY - 2023/2/17

Y1 - 2023/2/17

N2 - Although the photovoltaic performance of the composite of poly-3-hexylthiophene (P3HT) with semiconducting single-walled carbon nanotubes (s-SWCNT) is promising, the short-circuit current density jSC is much lower than that for typical polymer/fullerene composites. Out-of-phase electron spin echo (ESE) technique with laser excitation of the P3HT/s-SWCNT composite was used to clarify the origin of the poor photogeneration of free charges. The appearance of out-of-phase ESE signal is a solid proof that the charge-transfer state of P3HT+/s-SWCNT- is formed upon photoexcitation and the electron spins of P3HT+ and s-SWCNT- are correlated. No out-of-phase ESE signal was detected in the same experiment with pristine P3HT film. The out-of-phase ESE envelope modulation trace for P3HT/s-SWCNT composite was close to that for the polymer/fullerene photovoltaic composite PCDTBT/PC70BM, which implies a similar distance of initial charge separation in the range 2-4 nm. However, out-of-phase ESE signal decay with delay after laser flash increase for P3HT/s-SWCNT composite was much faster, with a characteristic time of 10 µs at 30 K. This points to the higher geminate recombination rate for the P3HT/s-SWCNT composite, which may be one of the reasons for the relatively poor photovoltaic performance of this system.

AB - Although the photovoltaic performance of the composite of poly-3-hexylthiophene (P3HT) with semiconducting single-walled carbon nanotubes (s-SWCNT) is promising, the short-circuit current density jSC is much lower than that for typical polymer/fullerene composites. Out-of-phase electron spin echo (ESE) technique with laser excitation of the P3HT/s-SWCNT composite was used to clarify the origin of the poor photogeneration of free charges. The appearance of out-of-phase ESE signal is a solid proof that the charge-transfer state of P3HT+/s-SWCNT- is formed upon photoexcitation and the electron spins of P3HT+ and s-SWCNT- are correlated. No out-of-phase ESE signal was detected in the same experiment with pristine P3HT film. The out-of-phase ESE envelope modulation trace for P3HT/s-SWCNT composite was close to that for the polymer/fullerene photovoltaic composite PCDTBT/PC70BM, which implies a similar distance of initial charge separation in the range 2-4 nm. However, out-of-phase ESE signal decay with delay after laser flash increase for P3HT/s-SWCNT composite was much faster, with a characteristic time of 10 µs at 30 K. This points to the higher geminate recombination rate for the P3HT/s-SWCNT composite, which may be one of the reasons for the relatively poor photovoltaic performance of this system.

KW - EPR

KW - carbon nanotube

KW - charge-transfer state

KW - organic photovoltaics

KW - semiconducting polymer

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85149001323&origin=inward&txGid=915961756968d7fc188d81a10c3d7b51

UR - https://www.mendeley.com/catalogue/82304587-edd6-3523-bf31-90eeaac41781/

U2 - 10.3390/ijms24044098

DO - 10.3390/ijms24044098

M3 - Article

C2 - 36835508

VL - 24

JO - International Journal of Molecular Sciences

JF - International Journal of Molecular Sciences

SN - 1661-6596

IS - 4

M1 - 4098

ER -