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Keivanidis PE, Itskos G, Kan Z, Aluicio-Sarduy E, Goudarzi H, Kamm V, Laquai F, Zhang W, Brabec C, Floudas G, McCulloch I. Afterglow Effects as a Tool to Screen Emissive Nongeminate Charge Recombination Processes in Organic Photovoltaic Composites. ACS APPLIED MATERIALS & INTERFACES 2020; 12:2695-2707. [PMID: 31854965 DOI: 10.1021/acsami.9b16036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Disentangling temporally overlapping charge carrier recombination events in organic bulk heterojunctions by optical spectroscopy is challenging. Here, a new methodology for employing delayed luminescence spectroscopy is presented. The proposed method is capable of distinguishing between recombination of spatially separated charge carriers and trap-assisted charge recombination simply by monitoring the delayed luminescence (afterglow) of bulk heterojunctions with a quasi time-integrated detection scheme. Applied on the model composite of the donor poly(6,12-dihydro-6,6,12,12-tetraoctyl-indeno[1,2-b]fluorene-alt-benzothiadiazole) (PIF8BT) polymer and the acceptor ethyl-propyl perylene diimide (PDI) derivative, that is, PIF8BT:PDI, the luminescence of charge-transfer (CT) states created by nongeminate charge recombination on the ns to μs timescale is observed. Fluence-dependent, quasi time-integrated detection of the CT luminescence monitors exclusively emissive charge recombination events, while rejecting the contribution of other early-time emissive processes. Trap-assisted and bimolecular charge recombination channels are identified based on their distinct dependence on fluence. The importance of the two recombination channels is correlated with the layer's order and electrical properties of the corresponding devices. Four different microstructures of the PIF8BT:PDI composite obtained by thermal annealing are investigated. Thermal annealing of PIF8BT:PDI shrinks the PDI domains in parallel with the growth of the PIF8BT domains in the blend. Common to all states studied, the delayed CT luminescence signal is dominated by trap-assisted recombination. Yet, the minor fraction of fully separated charge recombination in the overall CT emission increases as the difference in the size of the donor and acceptor domains in the PIF8BT:PDI blend becomes larger. Electric field-induced quenching measurements on complete PIF8BT:PDI devices confirm quantitatively the dominance of emissive trap-limited charge recombination and demonstrates that only 40% of the PIF8BT/PDI CT luminescence comes from the recombination of fully-separated charges, taking place within 200 ns after photoexcitation. The method is applicable to other nonfullerene acceptor blends beyond the system discussed here, if their CT state luminescence can be monitored.
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Affiliation(s)
- Panagiotis E Keivanidis
- Device Technology and Chemical Physics Lab, Department of Mechanical Engineering and Materials Science and Engineering , Cyprus University of Technology , Limassol 3041 , Cyprus
- Centre for Nano Science and Technology @PoliMi , Fondazione Istituto Italiano di Tecnologia , Via Pascoli 70/3 , Milano 20133 , Italy
| | - Grigorios Itskos
- Department of Physics, Experimental Condensed Matter Physics Laboratory , University of Cyprus , Nicosia 1678 , Cyprus
| | - Zhipeng Kan
- Centre for Nano Science and Technology @PoliMi , Fondazione Istituto Italiano di Tecnologia , Via Pascoli 70/3 , Milano 20133 , Italy
| | - Eduardo Aluicio-Sarduy
- Centre for Nano Science and Technology @PoliMi , Fondazione Istituto Italiano di Tecnologia , Via Pascoli 70/3 , Milano 20133 , Italy
| | - Hossein Goudarzi
- Centre for Nano Science and Technology @PoliMi , Fondazione Istituto Italiano di Tecnologia , Via Pascoli 70/3 , Milano 20133 , Italy
| | - Valentin Kamm
- Max Planck Institute for Polymer Research , Ackermannweg 10 , Mainz D-55128 , Germany
| | - Frédéric Laquai
- KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE) , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
| | - Weimin Zhang
- KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE) , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
- Department of Chemistry and Centre for Plastic Electronics , Imperial College London , London SW7 2AZ , United Kingdom
| | - Christoph Brabec
- Institute of Materials for Electronics and Energy Technology (I-MEET) , Friedrich-Alexander-University Erlangen-Nuremberg , Martensstraße 7 , Erlangen 91058 , Germany
- Bavarian Center for Applied Energy Research (ZAE Bayern) , Haberstrasse 2a , Erlangen 91058 , Germany
| | - George Floudas
- Max Planck Institute for Polymer Research , Ackermannweg 10 , Mainz D-55128 , Germany
- Department of Physics , University of Ioannina , Ioannina 451 10 , Greece
| | - Iain McCulloch
- KAUST Solar Center (KSC), Physical Sciences and Engineering Division (PSE) , King Abdullah University of Science and Technology (KAUST) , Thuwal 23955-6900 , Kingdom of Saudi Arabia
- Department of Chemistry and Centre for Plastic Electronics , Imperial College London , London SW7 2AZ , United Kingdom
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Foster S, Finlayson CE, Keivanidis PE, Huang YS, Hwang I, Friend RH, Otten MBJ, Lu LP, Schwartz E, Nolte RJM, Rowan AE. Improved Performance of Perylene-Based Photovoltaic Cells Using Polyisocyanopeptide Arrays. Macromolecules 2009. [DOI: 10.1021/ma801959w] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sam Foster
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Chris E. Finlayson
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Panagiotis E. Keivanidis
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Ya-Shih Huang
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Inchan Hwang
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Richard H. Friend
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Matthijs B. J. Otten
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Li-Ping Lu
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Erik Schwartz
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Roeland J. M. Nolte
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
| | - Alan E. Rowan
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, U.K., and Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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Worrall DR, Williams SL, Ganguly T. Ion–electron recombination on silica gel surfaces: experiment and modelling. Photochem Photobiol Sci 2006; 5:844-9. [PMID: 17047837 DOI: 10.1039/b608601b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Kinetics on silica gel and other solid, porous surfaces are often complex. In this paper we have studied the decay kinetics of radical cations produced following multiphoton ionisation on silica gel, and have characterised these using an empirical model. Trends in kinetics have been observed both as a function of concentration and of temperature. Concentration dependent studies suggest heterogeneity of surface adsorption, both in terms of the nature of adsorption sites and aggregation effects. Temperature dependent studies show that the activation energies for surface diffusion correlate with the size of the radical cation, suggesting that its movement rather than that of the electron dominates the observed kinetics. Monte Carlo simulations have been shown to give useful qualitative insights into the interpretation of the extracted parameters, in particular into how apparent distributions of rate constants can arise as a result of low surface dimensionality.
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Affiliation(s)
- David R Worrall
- Department of Chemistry, Loughborough University, Loughborough, Leicestershire
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