Thermal Annealing Reduces Geminate Recombination in TQ1:N2200 All-Polymer Solar Cells

Handle URI:
http://hdl.handle.net/10754/627393
Title:
Thermal Annealing Reduces Geminate Recombination in TQ1:N2200 All-Polymer Solar Cells
Authors:
Karuthedath, Safakath; Melianas, Armantas; Kan, Zhipeng; Pranculis, Vytenis; Wohlfahrt, Markus; Khan, Jafar Iqbal; Gorenflot, Julien; Xia, Yuxin; Inganäs, Olle; Gulbinas, Vidmantas; Kemerink, Martijn; Laquai, Frederic ( 0000-0002-5887-6158 )
Abstract:
A combination of steady-state and time-resolved spectroscopic measurements is used to investigate the photophysics of the all-polymer bulk heterojunction system TQ1:N2200. Upon thermal annealing a doubling of the external quantum efficiency and an improved fill factor (FF) is observed, resulting in an increase in the power conversion efficiency. Carrier extraction is similar for both blends, as demonstrated by time-resolved electric-field-induced second harmonic generation experiments in conjunction with transient photocurrent studies, spanning the ps-µs time range. Complementary transient absorption spectroscopy measurements reveal that the different quantum efficiencies originate from differences in charge carrier separation and recombination at the polymer-polymer interface: in as-spun samples ~35 % of the charges are bound in interfacial charge-transfer states and recombine geminately, while this pool is reduced to ~7 % in thermally-annealed sample, resulting in higher short-circuit currents. Time-delayed collection field experiments demonstrate a field-dependent charge generation process in as-spun samples, which reduces the FF. In contrast, field-dependence of charge generation is weak in annealed films. While both devices exhibit significant non-geminate recombination competing with charge extraction, causing low FFs, our results demonstrate that the donor/acceptor interface in all-polymer solar cells can be favourably altered to enhance charge separation, without compromising charge transport and extraction.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; KAUST Solar Center (KSC); Materials Science and Engineering Program
Citation:
Karuthedath S, Melianas A, Kan Z, Pranculis V, Wohlfahrt M, et al. (2018) Thermal Annealing Reduces Geminate Recombination in TQ1:N2200 All-Polymer Solar Cells. Journal of Materials Chemistry A. Available: http://dx.doi.org/10.1039/C8TA01692E.
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Journal of Materials Chemistry A
Issue Date:
27-Mar-2018
DOI:
10.1039/C8TA01692E
Type:
Article
ISSN:
2050-7488; 2050-7496
Sponsors:
The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). M. Wohlfahrt acknowledges a VSRP internship from KAUST. Research in Linköping University was funded by the Knut and Alice Wallenberg foundation and the Swedish Science council VR.
Additional Links:
http://pubs.rsc.org/en/Content/ArticleLanding/2018/TA/C8TA01692E#!divAbstract
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program; KAUST Solar Center (KSC)

Full metadata record

DC FieldValue Language
dc.contributor.authorKaruthedath, Safakathen
dc.contributor.authorMelianas, Armantasen
dc.contributor.authorKan, Zhipengen
dc.contributor.authorPranculis, Vytenisen
dc.contributor.authorWohlfahrt, Markusen
dc.contributor.authorKhan, Jafar Iqbalen
dc.contributor.authorGorenflot, Julienen
dc.contributor.authorXia, Yuxinen
dc.contributor.authorInganäs, Olleen
dc.contributor.authorGulbinas, Vidmantasen
dc.contributor.authorKemerink, Martijnen
dc.contributor.authorLaquai, Fredericen
dc.date.accessioned2018-04-01T08:20:28Z-
dc.date.available2018-04-01T08:20:28Z-
dc.date.issued2018-03-27en
dc.identifier.citationKaruthedath S, Melianas A, Kan Z, Pranculis V, Wohlfahrt M, et al. (2018) Thermal Annealing Reduces Geminate Recombination in TQ1:N2200 All-Polymer Solar Cells. Journal of Materials Chemistry A. Available: http://dx.doi.org/10.1039/C8TA01692E.en
dc.identifier.issn2050-7488en
dc.identifier.issn2050-7496en
dc.identifier.doi10.1039/C8TA01692Een
dc.identifier.urihttp://hdl.handle.net/10754/627393-
dc.description.abstractA combination of steady-state and time-resolved spectroscopic measurements is used to investigate the photophysics of the all-polymer bulk heterojunction system TQ1:N2200. Upon thermal annealing a doubling of the external quantum efficiency and an improved fill factor (FF) is observed, resulting in an increase in the power conversion efficiency. Carrier extraction is similar for both blends, as demonstrated by time-resolved electric-field-induced second harmonic generation experiments in conjunction with transient photocurrent studies, spanning the ps-µs time range. Complementary transient absorption spectroscopy measurements reveal that the different quantum efficiencies originate from differences in charge carrier separation and recombination at the polymer-polymer interface: in as-spun samples ~35 % of the charges are bound in interfacial charge-transfer states and recombine geminately, while this pool is reduced to ~7 % in thermally-annealed sample, resulting in higher short-circuit currents. Time-delayed collection field experiments demonstrate a field-dependent charge generation process in as-spun samples, which reduces the FF. In contrast, field-dependence of charge generation is weak in annealed films. While both devices exhibit significant non-geminate recombination competing with charge extraction, causing low FFs, our results demonstrate that the donor/acceptor interface in all-polymer solar cells can be favourably altered to enhance charge separation, without compromising charge transport and extraction.en
dc.description.sponsorshipThe research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST). M. Wohlfahrt acknowledges a VSRP internship from KAUST. Research in Linköping University was funded by the Knut and Alice Wallenberg foundation and the Swedish Science council VR.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.relation.urlhttp://pubs.rsc.org/en/Content/ArticleLanding/2018/TA/C8TA01692E#!divAbstracten
dc.rightsArchived with thanks to Journal of Materials Chemistry Aen
dc.titleThermal Annealing Reduces Geminate Recombination in TQ1:N2200 All-Polymer Solar Cellsen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentKAUST Solar Center (KSC)en
dc.contributor.departmentMaterials Science and Engineering Programen
dc.identifier.journalJournal of Materials Chemistry Aen
dc.eprint.versionPost-printen
dc.contributor.institutionDepartment of Physics, Chemistry and Biology, Biomolecular and Organic Electronics, Center of Organic Electronics (COE), Linköping University, 58183, Linköping , Sweden.en
dc.contributor.institutionCenter for Physical Sciences and Technology, Savanorių pr. 231, LT-02300 Vilnius, Lithuania.en
dc.contributor.institutionComplex Materials and Devices, Department of Physics, Chemistry and Biology, Linköping University, 58183, Linköping, Sweden.en
kaust.authorKaruthedath, Safakathen
kaust.authorKan, Zhipengen
kaust.authorWohlfahrt, Markusen
kaust.authorKhan, Jafar Iqbalen
kaust.authorGorenflot, Julienen
kaust.authorLaquai, Fredericen
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