Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible Electronics
Silver (Ag), gold (Au), and copper (Cu) have been utilized as metals for fabricating metal-based inks/pastes for printed/flexible electronics. Among them, Cu is the most promising candidate for metal-based inks/pastes. Cu has high intrinsic electrical/thermal conductivity, which is more cost-effecti...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-08-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/10/9/1689 |
| _version_ | 1797555333607981056 |
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| author | Daisuke Tomotoshi Hideya Kawasaki |
| author_facet | Daisuke Tomotoshi Hideya Kawasaki |
| author_sort | Daisuke Tomotoshi |
| collection | DOAJ |
| description | Silver (Ag), gold (Au), and copper (Cu) have been utilized as metals for fabricating metal-based inks/pastes for printed/flexible electronics. Among them, Cu is the most promising candidate for metal-based inks/pastes. Cu has high intrinsic electrical/thermal conductivity, which is more cost-effective and abundant, as compared to Ag. Moreover, the migration tendency of Cu is less than that of Ag. Thus, recently, Cu-based inks/pastes have gained increasing attention as conductive inks/pastes for printed/flexible electronics. However, the disadvantages of Cu-based inks/pastes are their instability against oxidation under an ambient condition and tendency to form insulating layers of Cu oxide, such as cuprous oxide (Cu<sub>2</sub>O) and cupric oxide (CuO). The formation of the Cu oxidation causes a low conductivity in sintered Cu films and interferes with the sintering of Cu particles. In this review, we summarize the surface and interface designs for Cu-based conductive inks/pastes, in which the strategies for the oxidation resistance of Cu and low-temperature sintering are applied to produce highly conductive Cu patterns/electrodes on flexible substrates. First, we classify the Cu-based inks/pastes and briefly describe the surface oxidation behaviors of Cu. Next, we describe various surface control approaches for Cu-based inks/pastes to achieve both the oxidation resistance and low-temperature sintering to produce highly conductive Cu patterns/electrodes on flexible substrates. These surface control approaches include surface designs by polymers, small ligands, core-shell structures, and surface activation. Recently developed Cu-based mixed inks/pastes are also described, and the synergy effect in the mixed inks/pastes offers improved performances compared with the single use of each component. Finally, we offer our perspectives on Cu-based inks/pastes for future efforts. |
| first_indexed | 2024-03-10T16:45:57Z |
| format | Article |
| id | doaj.art-880dc44bb73a4ba680e8127adee7dc8c |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T16:45:57Z |
| publishDate | 2020-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-880dc44bb73a4ba680e8127adee7dc8c2023-11-20T11:36:41ZengMDPI AGNanomaterials2079-49912020-08-01109168910.3390/nano10091689Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible ElectronicsDaisuke Tomotoshi0Hideya Kawasaki1Department of Chemistry and Materials Engineering, Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita-shi, Osaka 564-8680, JapanDepartment of Chemistry and Materials Engineering, Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita-shi, Osaka 564-8680, JapanSilver (Ag), gold (Au), and copper (Cu) have been utilized as metals for fabricating metal-based inks/pastes for printed/flexible electronics. Among them, Cu is the most promising candidate for metal-based inks/pastes. Cu has high intrinsic electrical/thermal conductivity, which is more cost-effective and abundant, as compared to Ag. Moreover, the migration tendency of Cu is less than that of Ag. Thus, recently, Cu-based inks/pastes have gained increasing attention as conductive inks/pastes for printed/flexible electronics. However, the disadvantages of Cu-based inks/pastes are their instability against oxidation under an ambient condition and tendency to form insulating layers of Cu oxide, such as cuprous oxide (Cu<sub>2</sub>O) and cupric oxide (CuO). The formation of the Cu oxidation causes a low conductivity in sintered Cu films and interferes with the sintering of Cu particles. In this review, we summarize the surface and interface designs for Cu-based conductive inks/pastes, in which the strategies for the oxidation resistance of Cu and low-temperature sintering are applied to produce highly conductive Cu patterns/electrodes on flexible substrates. First, we classify the Cu-based inks/pastes and briefly describe the surface oxidation behaviors of Cu. Next, we describe various surface control approaches for Cu-based inks/pastes to achieve both the oxidation resistance and low-temperature sintering to produce highly conductive Cu patterns/electrodes on flexible substrates. These surface control approaches include surface designs by polymers, small ligands, core-shell structures, and surface activation. Recently developed Cu-based mixed inks/pastes are also described, and the synergy effect in the mixed inks/pastes offers improved performances compared with the single use of each component. Finally, we offer our perspectives on Cu-based inks/pastes for future efforts.https://www.mdpi.com/2079-4991/10/9/1689coppernanoparticlescomplexesinkspastesprinted electronics |
| spellingShingle | Daisuke Tomotoshi Hideya Kawasaki Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible Electronics Nanomaterials copper nanoparticles complexes inks pastes printed electronics |
| title | Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible Electronics |
| title_full | Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible Electronics |
| title_fullStr | Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible Electronics |
| title_full_unstemmed | Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible Electronics |
| title_short | Surface and Interface Designs in Copper-Based Conductive Inks for Printed/Flexible Electronics |
| title_sort | surface and interface designs in copper based conductive inks for printed flexible electronics |
| topic | copper nanoparticles complexes inks pastes printed electronics |
| url | https://www.mdpi.com/2079-4991/10/9/1689 |
| work_keys_str_mv | AT daisuketomotoshi surfaceandinterfacedesignsincopperbasedconductiveinksforprintedflexibleelectronics AT hideyakawasaki surfaceandinterfacedesignsincopperbasedconductiveinksforprintedflexibleelectronics |