Efficient inverted bulk-heterojunction solar cells from low-temperature processing of amorphous ZnO buffer layers

Handle URI:
http://hdl.handle.net/10754/563227
Title:
Efficient inverted bulk-heterojunction solar cells from low-temperature processing of amorphous ZnO buffer layers
Authors:
Jagadamma, Lethy Krishnan ( 0000-0003-4226-017X ) ; Abdelsamie, Maged ( 0000-0002-4631-5409 ) ; El Labban, Abdulrahman ( 0000-0001-9891-0851 ) ; Aresu, Emanuele; Ngongang Ndjawa, Guy Olivier ( 0000-0001-7400-9540 ) ; Anjum, Dalaver H.; Cha, Dong Kyu; Beaujuge, Pierre; Amassian, Aram ( 0000-0002-5734-1194 )
Abstract:
In this report, we demonstrate that solution-processed amorphous zinc oxide (a-ZnO) interlayers prepared at low temperatures (∼100 °C) can yield inverted bulk-heterojunction (BHJ) solar cells that are as efficient as nanoparticle-based ZnO requiring comparably more complex synthesis or polycrystalline ZnO films prepared at substantially higher temperatures (150-400 °C). Low-temperature, facile solution-processing approaches are required in the fabrication of BHJ solar cells on flexible plastic substrates, such as PET. Here, we achieve efficient inverted solar cells with a-ZnO buffer layers by carefully examining the correlations between the thin film morphology and the figures of merit of optimized BHJ devices with various polymer donors and PCBM as the fullerene acceptor. We find that the most effective a-ZnO morphology consists of a compact, thin layer with continuous substrate coverage. In parallel, we emphasize the detrimental effect of forming rippled surface morphologies of a-ZnO, an observation which contrasts with results obtained in polycrystalline ZnO thin films, where rippled morphologies have been reported to improve efficiency. After optimizing the a-ZnO morphology at low processing temperature for inverted P3HT:PCBM devices, achieving a power conversion efficiency (PCE) of ca. 4.1%, we demonstrate inverted solar cells with low bandgap polymer donors on glass/flexible PET substrates: PTB7:PC71BM (PCE: 6.5% (glass)/5.6% (PET)) and PBDTTPD:PC71BM (PCE: 6.7% (glass)/5.9% (PET)). Finally, we show that a-ZnO based inverted P3HT:PCBM BHJ solar cells maintain ca. 90-95% of their initial PCE even after a full year without encapsulation in a nitrogen dry box, thus demonstrating excellent shelf stability. The insight we have gained into the importance of surface morphology in amorphous zinc oxide buffer layers should help in the development of other low-temperature solution-processed metal oxide interlayers for efficient flexible solar cells. This journal is © the Partner Organisations 2014.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Solar and Photovoltaic Engineering Research Center (SPERC); Advanced Nanofabrication, Imaging and Characterization Core Lab; Materials Science and Engineering Program; Core Labs; Chemical Science Program; Organic Electronics and Photovoltaics Group
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Journal of Materials Chemistry A
Issue Date:
2014
DOI:
10.1039/c4ta02276a
Type:
Article
ISSN:
20507488
Sponsors:
Authors would like to thank the KAUST Office of Competitive Research Funding. Authors thank Dr Liyang Yu for help with the contact angle measurements, as well as Muhammad Rizwan Khan Niazi and Dr Kui Zhao for helpful discussions and training.
Appears in Collections:
Articles; Advanced Nanofabrication, Imaging and Characterization Core Lab; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; Materials Science and Engineering Program; Solar and Photovoltaic Engineering Research Center (SPERC)

Full metadata record

DC FieldValue Language
dc.contributor.authorJagadamma, Lethy Krishnanen
dc.contributor.authorAbdelsamie, Mageden
dc.contributor.authorEl Labban, Abdulrahmanen
dc.contributor.authorAresu, Emanueleen
dc.contributor.authorNgongang Ndjawa, Guy Olivieren
dc.contributor.authorAnjum, Dalaver H.en
dc.contributor.authorCha, Dong Kyuen
dc.contributor.authorBeaujuge, Pierreen
dc.contributor.authorAmassian, Aramen
dc.date.accessioned2015-08-03T11:43:37Zen
dc.date.available2015-08-03T11:43:37Zen
dc.date.issued2014en
dc.identifier.issn20507488en
dc.identifier.doi10.1039/c4ta02276aen
dc.identifier.urihttp://hdl.handle.net/10754/563227en
dc.description.abstractIn this report, we demonstrate that solution-processed amorphous zinc oxide (a-ZnO) interlayers prepared at low temperatures (∼100 °C) can yield inverted bulk-heterojunction (BHJ) solar cells that are as efficient as nanoparticle-based ZnO requiring comparably more complex synthesis or polycrystalline ZnO films prepared at substantially higher temperatures (150-400 °C). Low-temperature, facile solution-processing approaches are required in the fabrication of BHJ solar cells on flexible plastic substrates, such as PET. Here, we achieve efficient inverted solar cells with a-ZnO buffer layers by carefully examining the correlations between the thin film morphology and the figures of merit of optimized BHJ devices with various polymer donors and PCBM as the fullerene acceptor. We find that the most effective a-ZnO morphology consists of a compact, thin layer with continuous substrate coverage. In parallel, we emphasize the detrimental effect of forming rippled surface morphologies of a-ZnO, an observation which contrasts with results obtained in polycrystalline ZnO thin films, where rippled morphologies have been reported to improve efficiency. After optimizing the a-ZnO morphology at low processing temperature for inverted P3HT:PCBM devices, achieving a power conversion efficiency (PCE) of ca. 4.1%, we demonstrate inverted solar cells with low bandgap polymer donors on glass/flexible PET substrates: PTB7:PC71BM (PCE: 6.5% (glass)/5.6% (PET)) and PBDTTPD:PC71BM (PCE: 6.7% (glass)/5.9% (PET)). Finally, we show that a-ZnO based inverted P3HT:PCBM BHJ solar cells maintain ca. 90-95% of their initial PCE even after a full year without encapsulation in a nitrogen dry box, thus demonstrating excellent shelf stability. The insight we have gained into the importance of surface morphology in amorphous zinc oxide buffer layers should help in the development of other low-temperature solution-processed metal oxide interlayers for efficient flexible solar cells. This journal is © the Partner Organisations 2014.en
dc.description.sponsorshipAuthors would like to thank the KAUST Office of Competitive Research Funding. Authors thank Dr Liyang Yu for help with the contact angle measurements, as well as Muhammad Rizwan Khan Niazi and Dr Kui Zhao for helpful discussions and training.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.titleEfficient inverted bulk-heterojunction solar cells from low-temperature processing of amorphous ZnO buffer layersen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentSolar and Photovoltaic Engineering Research Center (SPERC)en
dc.contributor.departmentAdvanced Nanofabrication, Imaging and Characterization Core Laben
dc.contributor.departmentMaterials Science and Engineering Programen
dc.contributor.departmentCore Labsen
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentOrganic Electronics and Photovoltaics Groupen
dc.identifier.journalJournal of Materials Chemistry Aen
kaust.authorJagadamma, Lethy Krishnanen
kaust.authorEl Labban, Abdulrahmanen
kaust.authorAnjum, Dalaver H.en
kaust.authorCha, Dong Kyuen
kaust.authorBeaujuge, Pierreen
kaust.authorAmassian, Aramen
kaust.authorAbdelsamie, Mageden
kaust.authorAresu, Emanueleen
kaust.authorNgongang Ndjawa, Guy Olivieren
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