Tuning interfacial charge-transfer excitons at polymer-polymer heterojunctions under hydrostatic pressure.
We present photoluminescence spectroscopy of blend thin films of poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) with electron-donating copolymers under hydrostatic pressure. The photoluminescence spectrum of F8BT redshifts by 530+/-60 meV over pressures of 0.1 MPa-8.8 GPa. That of the interfacial charge-transfer exciton redshifts by 270-370 meV over a similar pressure range. Despite the relatively small shift of the charge-transfer exciton, the excited state dynamics at the molecular heterojunction are strongly enhanced due to the decreasing intermolecular distance, leading to favored exciplex emission.
Schmidtke
Johanna P
JP
Cavendish Laboratory, University of Cambridge, J.J. Thompson Avenue, Cambridge, United Kingdom. jpschmidtke@gmail.com
Friend
Richard H
RH
Silva
Carlos
C