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Improved Exciton Dissociation at Semiconducting Polymer:ZnO Donor:Acceptor Interfaces via Nitrogen Doping of ZnO.

Musselman KP, Albert-Seifried S, Hoye RL, Sadhanala A, Muñoz-Rojas D, MacManus-Driscoll JL, Friend RH - Adv Funct Mater (2014)

Bottom Line: Exciton dissociation at the zinc oxide/poly(3-hexylthiophene) (ZnO/P3HT) interface as a function of nitrogen doping of the zinc oxide, which decreases the electron concentration from approximately 10(19) cm(-3) to 10(17) cm(-3), is reported.This improved dissociation of excitons in the conjugated polymer is found to result from enhanced light-induced de-trapping of electrons from the surface of the nitrogen-doped ZnO.The ability to improve the surface properties of ZnO by introducing a simple nitrogen dopant has general applicability.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics University of Cambridge Cavendish Laboratory JJ Thomson Ave Cambridge, CB3 0HE, UK E-mail: kpdm2@cam.ac.uk.

ABSTRACT

Exciton dissociation at the zinc oxide/poly(3-hexylthiophene) (ZnO/P3HT) interface as a function of nitrogen doping of the zinc oxide, which decreases the electron concentration from approximately 10(19) cm(-3) to 10(17) cm(-3), is reported. Exciton dissociation and device photocurrent are strongly improved with nitrogen doping. This improved dissociation of excitons in the conjugated polymer is found to result from enhanced light-induced de-trapping of electrons from the surface of the nitrogen-doped ZnO. The ability to improve the surface properties of ZnO by introducing a simple nitrogen dopant has general applicability.

No MeSH data available.


Related in: MedlinePlus

EQE measurements of ZnO/P3HT and ZnO/ZnO:N/P3HT devices after storing in the dark and after illuminating with simulated solar light.
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fig05: EQE measurements of ZnO/P3HT and ZnO/ZnO:N/P3HT devices after storing in the dark and after illuminating with simulated solar light.

Mentions: We propose that the surface of the oxide, which is directly adjacent to the P3HT, critically influences charge transfer from the P3HT, and that the lower photocurrents obtained with the undoped ZnO surfaces in Figure 2follow from a larger density of adsorbed molecules and/or trapped electrons on the surface, which inhibit exciton dissociation and charge transfer from the P3HT to the oxide. If the improved solar cell performance we have measured for the cells incorporating ZnO:N films (Figure 2) is in fact due to more efficient photo-induced removal of surface-localized species from the ZnO:N (and subsequently more efficient exciton dissociation and charge transfer from the adjacent P3HT), we would expect to see a change in the photovoltaic performance of the nitrogen-doped devices after they have been exposed to illumination. Figure5 shows the EQE of devices similar to those shown in Figure 2c (approximately 60 nm of ZnO with and without a ZnO:N surface coating) before and after illumination under simulated solar light. For the device with no surface coating, the EQE increases slightly with solar illumination, whereas for the device with the 20 nm ZnO:N coating, the EQE more than doubles after illumination, clearly demonstrating that the improved performance of the nitrogen-doped devices is induced by light exposure. In particular, absorption of ultraviolet light by the ZnO:N was found to be responsible for the improved performance. When a 440 nm long-pass filter was used to remove ultraviolet light from the simulated solar spectrum, the device with ZnO:N did not demonstrate an improvement in EQE after illumination for 5 min. When the filter was removed, the observed improvement in EQE was observed to take place within 1 min.


Improved Exciton Dissociation at Semiconducting Polymer:ZnO Donor:Acceptor Interfaces via Nitrogen Doping of ZnO.

Musselman KP, Albert-Seifried S, Hoye RL, Sadhanala A, Muñoz-Rojas D, MacManus-Driscoll JL, Friend RH - Adv Funct Mater (2014)

EQE measurements of ZnO/P3HT and ZnO/ZnO:N/P3HT devices after storing in the dark and after illuminating with simulated solar light.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4228972&req=5

fig05: EQE measurements of ZnO/P3HT and ZnO/ZnO:N/P3HT devices after storing in the dark and after illuminating with simulated solar light.
Mentions: We propose that the surface of the oxide, which is directly adjacent to the P3HT, critically influences charge transfer from the P3HT, and that the lower photocurrents obtained with the undoped ZnO surfaces in Figure 2follow from a larger density of adsorbed molecules and/or trapped electrons on the surface, which inhibit exciton dissociation and charge transfer from the P3HT to the oxide. If the improved solar cell performance we have measured for the cells incorporating ZnO:N films (Figure 2) is in fact due to more efficient photo-induced removal of surface-localized species from the ZnO:N (and subsequently more efficient exciton dissociation and charge transfer from the adjacent P3HT), we would expect to see a change in the photovoltaic performance of the nitrogen-doped devices after they have been exposed to illumination. Figure5 shows the EQE of devices similar to those shown in Figure 2c (approximately 60 nm of ZnO with and without a ZnO:N surface coating) before and after illumination under simulated solar light. For the device with no surface coating, the EQE increases slightly with solar illumination, whereas for the device with the 20 nm ZnO:N coating, the EQE more than doubles after illumination, clearly demonstrating that the improved performance of the nitrogen-doped devices is induced by light exposure. In particular, absorption of ultraviolet light by the ZnO:N was found to be responsible for the improved performance. When a 440 nm long-pass filter was used to remove ultraviolet light from the simulated solar spectrum, the device with ZnO:N did not demonstrate an improvement in EQE after illumination for 5 min. When the filter was removed, the observed improvement in EQE was observed to take place within 1 min.

Bottom Line: Exciton dissociation at the zinc oxide/poly(3-hexylthiophene) (ZnO/P3HT) interface as a function of nitrogen doping of the zinc oxide, which decreases the electron concentration from approximately 10(19) cm(-3) to 10(17) cm(-3), is reported.This improved dissociation of excitons in the conjugated polymer is found to result from enhanced light-induced de-trapping of electrons from the surface of the nitrogen-doped ZnO.The ability to improve the surface properties of ZnO by introducing a simple nitrogen dopant has general applicability.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics University of Cambridge Cavendish Laboratory JJ Thomson Ave Cambridge, CB3 0HE, UK E-mail: kpdm2@cam.ac.uk.

ABSTRACT

Exciton dissociation at the zinc oxide/poly(3-hexylthiophene) (ZnO/P3HT) interface as a function of nitrogen doping of the zinc oxide, which decreases the electron concentration from approximately 10(19) cm(-3) to 10(17) cm(-3), is reported. Exciton dissociation and device photocurrent are strongly improved with nitrogen doping. This improved dissociation of excitons in the conjugated polymer is found to result from enhanced light-induced de-trapping of electrons from the surface of the nitrogen-doped ZnO. The ability to improve the surface properties of ZnO by introducing a simple nitrogen dopant has general applicability.

No MeSH data available.


Related in: MedlinePlus