Impact of Aggregation on the Photochemistry of Fullerene Films: Correlating Stability to Triplet Exciton Kinetics

Emily M. Speller; James D. McGettrick; Beth Rice; Andrew M. Telford; Harrison K.H. Lee; Ching Hong Tan; Catherine S. De Castro; Matthew L. Davies; Trystan M. Watson; Jenny Nelson; James R. Durrant; Zhe Li; Wing C. Tsoi

doi:10.1021/acsami.7b03298

Impact of Aggregation on the Photochemistry of Fullerene Films: Correlating Stability to Triplet Exciton Kinetics

Emily M. Speller, James D. McGettrick, Beth Rice, Andrew M. Telford, Harrison K.H. Lee, Ching Hong Tan, Catherine S. De Castro, Matthew L. Davies, Trystan M. Watson, Jenny Nelson, James R. Durrant, Zhe Li^*, Wing C. Tsoi

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

30 Scopus citations

Abstract

The photochemistry and stability of fullerene films is found to be strongly dependent upon film nanomorphology. In particular, PC₆₁BM blend films, dispersed with polystyrene, are found to be more susceptible to photobleaching in air than the more aggregated neat films. This enhanced photobleaching correlated with increased oxygen quenching of PC₆₁BM triplet states and the appearance of a carbonyl FTIR absorption band indicative of fullerene oxidation, suggesting PC₆₁BM photo-oxidation is primarily due to triplet-mediated singlet oxygen generation. PC₆₁BM films were observed to undergo photo-oxidation in air for even modest (≤40 min) irradiation times, degrading electron mobility substantially, indicative of electron trap formation. This conclusion is supported by observation of red shifts in photo- and electro-luminescence with photo-oxidation, shown to be in agreement with time-dependent density functional theory calculations of defect generation. These results provide important implications on the environmental stability of PC₆₁BM-based films and devices.

Original language	English (US)
Pages (from-to)	22739-22747
Number of pages	9
Journal	ACS Applied Materials and Interfaces
Volume	9
Issue number	27
DOIs	https://doi.org/10.1021/acsami.7b03298
State	Published - Jul 12 2017

Bibliographical note

Funding Information:
The authors would like to acknowledge the funding from the Ser Cymru Programme: National Research Network in Advanced Engineering Materials (grant number NRN093), Welsh Assembly Government funded Ser Cymru Solar Project, the J.R.D. funding from the EU Cheetah project, and EPSRC grants EP/M025020/1 (Supergen Solar Challenge) and EP/K030671/1.

Publisher Copyright:
© 2017 American Chemical Society.

Keywords

aggregation
fullerenes
PCBM
photo-oxidation
stability
triplet exciton kinetics

ASJC Scopus subject areas

General Materials Science

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10.1021/acsami.7b03298

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Speller, E. M., McGettrick, J. D., Rice, B., Telford, A. M., Lee, H. K. H., Tan, C. H., De Castro, C. S., Davies, M. L., Watson, T. M., Nelson, J., Durrant, J. R., Li, Z., & Tsoi, W. C. (2017). Impact of Aggregation on the Photochemistry of Fullerene Films: Correlating Stability to Triplet Exciton Kinetics. ACS Applied Materials and Interfaces, 9(27), 22739-22747. https://doi.org/10.1021/acsami.7b03298

@article{538f1f099d4c4c18a6f3a60034e60421,

title = "Impact of Aggregation on the Photochemistry of Fullerene Films: Correlating Stability to Triplet Exciton Kinetics",

abstract = "The photochemistry and stability of fullerene films is found to be strongly dependent upon film nanomorphology. In particular, PC61BM blend films, dispersed with polystyrene, are found to be more susceptible to photobleaching in air than the more aggregated neat films. This enhanced photobleaching correlated with increased oxygen quenching of PC61BM triplet states and the appearance of a carbonyl FTIR absorption band indicative of fullerene oxidation, suggesting PC61BM photo-oxidation is primarily due to triplet-mediated singlet oxygen generation. PC61BM films were observed to undergo photo-oxidation in air for even modest (≤40 min) irradiation times, degrading electron mobility substantially, indicative of electron trap formation. This conclusion is supported by observation of red shifts in photo- and electro-luminescence with photo-oxidation, shown to be in agreement with time-dependent density functional theory calculations of defect generation. These results provide important implications on the environmental stability of PC61BM-based films and devices.",

keywords = "aggregation, fullerenes, PCBM, photo-oxidation, stability, triplet exciton kinetics",

author = "Speller, {Emily M.} and McGettrick, {James D.} and Beth Rice and Telford, {Andrew M.} and Lee, {Harrison K.H.} and Tan, {Ching Hong} and {De Castro}, {Catherine S.} and Davies, {Matthew L.} and Watson, {Trystan M.} and Jenny Nelson and Durrant, {James R.} and Zhe Li and Tsoi, {Wing C.}",

note = "Funding Information: The authors would like to acknowledge the funding from the Ser Cymru Programme: National Research Network in Advanced Engineering Materials (grant number NRN093), Welsh Assembly Government funded Ser Cymru Solar Project, the J.R.D. funding from the EU Cheetah project, and EPSRC grants EP/M025020/1 (Supergen Solar Challenge) and EP/K030671/1. Publisher Copyright: {\textcopyright} 2017 American Chemical Society.",

year = "2017",

month = jul,

day = "12",

doi = "10.1021/acsami.7b03298",

language = "English (US)",

volume = "9",

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Speller, EM, McGettrick, JD, Rice, B, Telford, AM, Lee, HKH, Tan, CH, De Castro, CS, Davies, ML, Watson, TM, Nelson, J, Durrant, JR, Li, Z & Tsoi, WC 2017, 'Impact of Aggregation on the Photochemistry of Fullerene Films: Correlating Stability to Triplet Exciton Kinetics', ACS Applied Materials and Interfaces, vol. 9, no. 27, pp. 22739-22747. https://doi.org/10.1021/acsami.7b03298

TY - JOUR

T1 - Impact of Aggregation on the Photochemistry of Fullerene Films

T2 - Correlating Stability to Triplet Exciton Kinetics

AU - Speller, Emily M.

AU - McGettrick, James D.

AU - Rice, Beth

AU - Telford, Andrew M.

AU - Lee, Harrison K.H.

AU - Tan, Ching Hong

AU - De Castro, Catherine S.

AU - Davies, Matthew L.

AU - Watson, Trystan M.

AU - Nelson, Jenny

AU - Durrant, James R.

AU - Li, Zhe

AU - Tsoi, Wing C.

N1 - Funding Information: The authors would like to acknowledge the funding from the Ser Cymru Programme: National Research Network in Advanced Engineering Materials (grant number NRN093), Welsh Assembly Government funded Ser Cymru Solar Project, the J.R.D. funding from the EU Cheetah project, and EPSRC grants EP/M025020/1 (Supergen Solar Challenge) and EP/K030671/1. Publisher Copyright: © 2017 American Chemical Society.

PY - 2017/7/12

Y1 - 2017/7/12

N2 - The photochemistry and stability of fullerene films is found to be strongly dependent upon film nanomorphology. In particular, PC61BM blend films, dispersed with polystyrene, are found to be more susceptible to photobleaching in air than the more aggregated neat films. This enhanced photobleaching correlated with increased oxygen quenching of PC61BM triplet states and the appearance of a carbonyl FTIR absorption band indicative of fullerene oxidation, suggesting PC61BM photo-oxidation is primarily due to triplet-mediated singlet oxygen generation. PC61BM films were observed to undergo photo-oxidation in air for even modest (≤40 min) irradiation times, degrading electron mobility substantially, indicative of electron trap formation. This conclusion is supported by observation of red shifts in photo- and electro-luminescence with photo-oxidation, shown to be in agreement with time-dependent density functional theory calculations of defect generation. These results provide important implications on the environmental stability of PC61BM-based films and devices.

AB - The photochemistry and stability of fullerene films is found to be strongly dependent upon film nanomorphology. In particular, PC61BM blend films, dispersed with polystyrene, are found to be more susceptible to photobleaching in air than the more aggregated neat films. This enhanced photobleaching correlated with increased oxygen quenching of PC61BM triplet states and the appearance of a carbonyl FTIR absorption band indicative of fullerene oxidation, suggesting PC61BM photo-oxidation is primarily due to triplet-mediated singlet oxygen generation. PC61BM films were observed to undergo photo-oxidation in air for even modest (≤40 min) irradiation times, degrading electron mobility substantially, indicative of electron trap formation. This conclusion is supported by observation of red shifts in photo- and electro-luminescence with photo-oxidation, shown to be in agreement with time-dependent density functional theory calculations of defect generation. These results provide important implications on the environmental stability of PC61BM-based films and devices.

KW - aggregation

KW - fullerenes

KW - PCBM

KW - photo-oxidation

KW - stability

KW - triplet exciton kinetics

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U2 - 10.1021/acsami.7b03298

DO - 10.1021/acsami.7b03298

M3 - Article

C2 - 28603957

AN - SCOPUS:85023764250

SN - 1944-8244

VL - 9

SP - 22739

EP - 22747

JO - ACS Applied Materials and Interfaces

JF - ACS Applied Materials and Interfaces

IS - 27

ER -

Impact of Aggregation on the Photochemistry of Fullerene Films: Correlating Stability to Triplet Exciton Kinetics

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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