In situ UV-visible absorption during spin-coating of organic semiconductors: A new probe for organic electronics and photovoltaics

Handle URI:
http://hdl.handle.net/10754/563188
Title:
In situ UV-visible absorption during spin-coating of organic semiconductors: A new probe for organic electronics and photovoltaics
Authors:
Abdelsamie, Maged ( 0000-0002-4631-5409 ) ; Zhao, Kui ( 0000-0001-9348-7943 ) ; Niazi, Muhammad Rizwan ( 0000-0003-0449-1559 ) ; Chou, Kang Wei; Amassian, Aram ( 0000-0002-5734-1194 )
Abstract:
Spin-coating is the most commonly used technique for the lab-scale production of solution processed organic electronic, optoelectronic and photovoltaic devices. Spin-coating produces the most efficient solution-processed organic solar cells and has been the preferred approach for rapid screening and optimization of new organic semiconductors and formulations for electronic and optoelectronic applications, both in academia and in industrial research facilities. In this article we demonstrate, for the first time, a spin-coating experiment monitored in situ by time resolved UV-visible absorption, the most commonly used, simplest, most direct and robust optical diagnostic tool used in organic electronics. In the first part, we successfully monitor the solution-to-solid phase transformation and thin film formation of poly(3-hexylthiophene) (P3HT), the de facto reference conjugated polymer in organic electronics and photovoltaics. We do so in two scenarios which differ by the degree of polymer aggregation in solution, prior to spin-coating. We find that a higher degree of aggregation in the starting solution results in small but measurable differences in the solid state, which translate into significant improvements in the charge carrier mobility of organic field-effect transistors (OFET). In the second part, we monitor the formation of a bulk heterojunction photoactive layer based on a P3HT-fullerene blend. We find that the spin-coating conditions that lead to slower kinetics of thin film formation favour a higher degree of polymer aggregation in the solid state and increased conjugation length along the polymer backbone. Using this insight, we devise an experiment in which the spin-coating process is interrupted prematurely, i.e., after liquid ejection is completed and before the film has started to form, so as to dramatically slow the thin film formation kinetics, while maintaining the same thickness and uniformity. These changes yield substantial improvements to the power conversion efficiency of solar cells without requiring additional thermal annealing, or the use of solvent additives. Through these simple examples, we demonstrate that gaining insight into the thin film formation process can inspire the development of new processing strategies. The insight into the inner workings of spin-coating may be increasingly important to improving the performance or efficiency of roll-to-roll manufactured devices. This journal is © the Partner Organisations 2014.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Solar and Photovoltaic Engineering Research Center (SPERC); Materials Science and Engineering Program; Organic Electronics and Photovoltaics Group
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Journal of Materials Chemistry C
Issue Date:
2014
DOI:
10.1039/c3tc32077d
Type:
Article
ISSN:
20507534
Sponsors:
We would like to acknowledge the technical support of the workshop team at the King Abdullah University of Science and Technology (KAUST), namely Mr Ali Khoder Raad, Mr Meshal Abdulkareem, Mr Yang Liu and Mr Yousef I. Al Mosri, for their valuable assistance with the designing and building of the spin coater for the in-situ UV-vis absorption measurements. We would like to thank Ms Anastasia Khrenova for assistance with photography. Part of this work was funded by the Office of Competitive Research Funds (OCRF) under FIC, CRG and AEA grants.
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Materials Science and Engineering Program; Solar and Photovoltaic Engineering Research Center (SPERC)

Full metadata record

DC FieldValue Language
dc.contributor.authorAbdelsamie, Mageden
dc.contributor.authorZhao, Kuien
dc.contributor.authorNiazi, Muhammad Rizwanen
dc.contributor.authorChou, Kang Weien
dc.contributor.authorAmassian, Aramen
dc.date.accessioned2015-08-03T11:37:46Zen
dc.date.available2015-08-03T11:37:46Zen
dc.date.issued2014en
dc.identifier.issn20507534en
dc.identifier.doi10.1039/c3tc32077den
dc.identifier.urihttp://hdl.handle.net/10754/563188en
dc.description.abstractSpin-coating is the most commonly used technique for the lab-scale production of solution processed organic electronic, optoelectronic and photovoltaic devices. Spin-coating produces the most efficient solution-processed organic solar cells and has been the preferred approach for rapid screening and optimization of new organic semiconductors and formulations for electronic and optoelectronic applications, both in academia and in industrial research facilities. In this article we demonstrate, for the first time, a spin-coating experiment monitored in situ by time resolved UV-visible absorption, the most commonly used, simplest, most direct and robust optical diagnostic tool used in organic electronics. In the first part, we successfully monitor the solution-to-solid phase transformation and thin film formation of poly(3-hexylthiophene) (P3HT), the de facto reference conjugated polymer in organic electronics and photovoltaics. We do so in two scenarios which differ by the degree of polymer aggregation in solution, prior to spin-coating. We find that a higher degree of aggregation in the starting solution results in small but measurable differences in the solid state, which translate into significant improvements in the charge carrier mobility of organic field-effect transistors (OFET). In the second part, we monitor the formation of a bulk heterojunction photoactive layer based on a P3HT-fullerene blend. We find that the spin-coating conditions that lead to slower kinetics of thin film formation favour a higher degree of polymer aggregation in the solid state and increased conjugation length along the polymer backbone. Using this insight, we devise an experiment in which the spin-coating process is interrupted prematurely, i.e., after liquid ejection is completed and before the film has started to form, so as to dramatically slow the thin film formation kinetics, while maintaining the same thickness and uniformity. These changes yield substantial improvements to the power conversion efficiency of solar cells without requiring additional thermal annealing, or the use of solvent additives. Through these simple examples, we demonstrate that gaining insight into the thin film formation process can inspire the development of new processing strategies. The insight into the inner workings of spin-coating may be increasingly important to improving the performance or efficiency of roll-to-roll manufactured devices. This journal is © the Partner Organisations 2014.en
dc.description.sponsorshipWe would like to acknowledge the technical support of the workshop team at the King Abdullah University of Science and Technology (KAUST), namely Mr Ali Khoder Raad, Mr Meshal Abdulkareem, Mr Yang Liu and Mr Yousef I. Al Mosri, for their valuable assistance with the designing and building of the spin coater for the in-situ UV-vis absorption measurements. We would like to thank Ms Anastasia Khrenova for assistance with photography. Part of this work was funded by the Office of Competitive Research Funds (OCRF) under FIC, CRG and AEA grants.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.titleIn situ UV-visible absorption during spin-coating of organic semiconductors: A new probe for organic electronics and photovoltaicsen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentSolar and Photovoltaic Engineering Research Center (SPERC)en
dc.contributor.departmentMaterials Science and Engineering Programen
dc.contributor.departmentOrganic Electronics and Photovoltaics Groupen
dc.identifier.journalJournal of Materials Chemistry Cen
kaust.authorZhao, Kuien
kaust.authorChou, Kang Weien
kaust.authorAmassian, Aramen
kaust.authorAbdelsamie, Mageden
kaust.authorNiazi, Muhammad Rizwanen
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