Low Work Function Lacunary Polyoxometalates as Electron Transport Interlayers for Inverted Polymer Solar Cells of Improved Efficiency and Stability
Authors
Tountas, MarinosTopal, Yasemin
Polydorou, Ermioni
Soultati, Anastasia
Verykios, Apostolos
Kaltzoglou, Andreas
Papadopoulos, Theodoros A.
Auras, Florian
Seintis, Kostas
Fakis, Mihalis
Palilis, Leonidas C.
Tsikritzis, Dimitris
Kennou, Stella
Koutsoureli, Matroni
Papaioannou, Georgios
Ersoz, Mustafa
Kus, Mahmut
Falaras, Polycarpos
Davazoglou, Dimitris
Argitis, Panagiotis
Vasilopoulou, Maria
Affiliation
National Center for Scientific Research Demokritos; Selcuk University Advanced Technology Research and Application Center; University of Patras; University of Chester; University of Munich; University of AthensPublication Date
2017-06-06
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Effective interface engineering has been shown to play a vital role in facilitating efficient charge-carrier transport, thus boosting the performance of organic photovoltaic devices. Herein, we employ water-soluble lacunary polyoxometalates (POMs) as multifunctional interlayers between the titanium dioxide (TiO2) electron extraction/transport layer and the organic photoactive film to simultaneously enhance the efficiency, lifetime, and photostability of polymer solar cells (PSCs). A significant reduction in the work function (WF) of TiO2 upon POM utilization was observed, with the magnitude being controlled by the negative charge of the anion and the selection of the addenda atom (W or Mo). By inserting a POM interlayer with ∼10 nm thickness into the device structure, a significant improvement in the power conversion efficiency was obtained; the optimized POM-modified poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl][3-fluoro-2-[(2- 33 ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl]]:[6,6]-phenyl-C70 butyric acid methyl ester (PTB7:PC70BM)-based PSCs exhibited an efficiency of 8.07%, which represents a 21% efficiency enhancement compared to the reference TiO2 cell. Similar results were obtained in POM-modified devices based on poly(3-hexylthiophene) (P3HT) with electron acceptors of different energy levels, such as PC70BM or indene-C60 bisadduct (IC60BA), which enhanced their efficiency up to 4.34 and 6.21%, respectively, when using POM interlayers; this represents a 25–33% improvement as compared to the reference cells. Moreover, increased lifetime under ambient air and improved photostability under constant illumination were observed in POM-modified devices. Detailed analysis shows that the improvements in efficiency and stability synergistically stem from the reduced work function of TiO2 upon POM coverage, the improved nanomorphology of the photoactive blend, the reduced interfacial recombination losses, the superior electron transfer, and the more effective exciton dissociation at the photoactive layer/POM/TiO2 interfaces.Citation
Tountas, M., et. al. (2017). Low Work Function Lacunary Polyoxometalates as Electron Transport Interlayers for Inverted Polymer Solar Cells of Improved Efficiency and Stability. ACS Applied Materials and Interfaces, 9(27), 22773-22787. DOI: 10.1021/acsami.7b04600Publisher
American Chemical SocietyAdditional Links
http://pubs.acs.org/doi/abs/10.1021/acsami.7b04600Type
ArticleLanguage
enDescription
This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acsami.7b04600ISSN
1944-8244EISSN
1944-8252ae974a485f413a2113503eed53cd6c53
10.1021/acsami.7b04600
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