A Low-Cost and Lithium-Free Hole Transport Layer for Efficient and Stable Normal Perovskite Solar Cells
The most widely used material as a hole-transport layer (HTL) for effective normal perovskite solar cells (PSCs) is still 2,2′,7,7′-Tetrakis[N, N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro-OMeTAD), which requires heavy doping with the hydroscopic Lithium bis(trifluoromethanesulfonyl)imide...
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MDPI AG
2023-02-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/13/5/883 |
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| author | Nikolaos Tzoganakis Dimitris Tsikritzis Konstantinos Chatzimanolis Xiaodong Zhuang Emmanuel Kymakis |
| author_facet | Nikolaos Tzoganakis Dimitris Tsikritzis Konstantinos Chatzimanolis Xiaodong Zhuang Emmanuel Kymakis |
| author_sort | Nikolaos Tzoganakis |
| collection | DOAJ |
| description | The most widely used material as a hole-transport layer (HTL) for effective normal perovskite solar cells (PSCs) is still 2,2′,7,7′-Tetrakis[N, N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro-OMeTAD), which requires heavy doping with the hydroscopic Lithium bis(trifluoromethanesulfonyl)imide (Li-ΤFSI). However, the long-term stability and performance of PCSs are frequently hampered by the residual insoluble dopants in the HTL, Li<sup>+</sup> diffusion throughout the device, dopant by-products, and the hygroscopic nature of Li-TFSI. Due to the high cost of Spiro-OMeTAD, alternative efficient low-cost HTLs, such as octakis(4-methoxyphenyl)spiro[fluorene-9,9′-xanthene]-2,2′,7,7′-tetraamine) (X60), have attracted attention. However, they require doping with Li-TFSI, and the devices develop the same Li-TFSI-derived problems. Here, we propose Li-free 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI) as an efficient p-type dopant of X60, resulting in a high-quality HTL with enhanced conductivity and deeper energy levels The optimized X60:EMIM-TFSI-enabled devices exhibit a higher efficiency of 21.85% and improved stability, compared to the Li-TFSI-doped X60 devices. The stability of the optimized EMIM-TFSI-doped PSCs is greatly improved, and after 1200 hr of storage under ambient conditions, the resulting PSCs maintain 85% of the initial PCE. These findings offer a fresh method for doping the cost effective X60 as the HTL with a Li-free alternative dopant for efficient, cheaper, and reliable planar PSCs. |
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| language | English |
| last_indexed | 2024-03-11T07:15:11Z |
| publishDate | 2023-02-01 |
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| series | Nanomaterials |
| spelling | doaj.art-0c989c39f819403ea277187ce808df022023-11-17T08:17:50ZengMDPI AGNanomaterials2079-49912023-02-0113588310.3390/nano13050883A Low-Cost and Lithium-Free Hole Transport Layer for Efficient and Stable Normal Perovskite Solar CellsNikolaos Tzoganakis0Dimitris Tsikritzis1Konstantinos Chatzimanolis2Xiaodong Zhuang3Emmanuel Kymakis4Department of Electrical & Computer Engineering, Hellenic Mediterranean University (HMU), 71410 Heraklion, Crete, GreeceDepartment of Electrical & Computer Engineering, Hellenic Mediterranean University (HMU), 71410 Heraklion, Crete, GreeceDepartment of Electrical & Computer Engineering, Hellenic Mediterranean University (HMU), 71410 Heraklion, Crete, GreeceMeso-Entropy Matter Lab, State Key Laboratory of Metal Matrix Composites Shangai Key Laboratory of Electrical Insulation and Thermal Gaining, School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, ChinaDepartment of Electrical & Computer Engineering, Hellenic Mediterranean University (HMU), 71410 Heraklion, Crete, GreeceThe most widely used material as a hole-transport layer (HTL) for effective normal perovskite solar cells (PSCs) is still 2,2′,7,7′-Tetrakis[N, N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro-OMeTAD), which requires heavy doping with the hydroscopic Lithium bis(trifluoromethanesulfonyl)imide (Li-ΤFSI). However, the long-term stability and performance of PCSs are frequently hampered by the residual insoluble dopants in the HTL, Li<sup>+</sup> diffusion throughout the device, dopant by-products, and the hygroscopic nature of Li-TFSI. Due to the high cost of Spiro-OMeTAD, alternative efficient low-cost HTLs, such as octakis(4-methoxyphenyl)spiro[fluorene-9,9′-xanthene]-2,2′,7,7′-tetraamine) (X60), have attracted attention. However, they require doping with Li-TFSI, and the devices develop the same Li-TFSI-derived problems. Here, we propose Li-free 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI) as an efficient p-type dopant of X60, resulting in a high-quality HTL with enhanced conductivity and deeper energy levels The optimized X60:EMIM-TFSI-enabled devices exhibit a higher efficiency of 21.85% and improved stability, compared to the Li-TFSI-doped X60 devices. The stability of the optimized EMIM-TFSI-doped PSCs is greatly improved, and after 1200 hr of storage under ambient conditions, the resulting PSCs maintain 85% of the initial PCE. These findings offer a fresh method for doping the cost effective X60 as the HTL with a Li-free alternative dopant for efficient, cheaper, and reliable planar PSCs.https://www.mdpi.com/2079-4991/13/5/883perovskite solar cellhole transport layerX60Li-TFSIEMIM-TFSIstability |
| spellingShingle | Nikolaos Tzoganakis Dimitris Tsikritzis Konstantinos Chatzimanolis Xiaodong Zhuang Emmanuel Kymakis A Low-Cost and Lithium-Free Hole Transport Layer for Efficient and Stable Normal Perovskite Solar Cells Nanomaterials perovskite solar cell hole transport layer X60 Li-TFSI EMIM-TFSI stability |
| title | A Low-Cost and Lithium-Free Hole Transport Layer for Efficient and Stable Normal Perovskite Solar Cells |
| title_full | A Low-Cost and Lithium-Free Hole Transport Layer for Efficient and Stable Normal Perovskite Solar Cells |
| title_fullStr | A Low-Cost and Lithium-Free Hole Transport Layer for Efficient and Stable Normal Perovskite Solar Cells |
| title_full_unstemmed | A Low-Cost and Lithium-Free Hole Transport Layer for Efficient and Stable Normal Perovskite Solar Cells |
| title_short | A Low-Cost and Lithium-Free Hole Transport Layer for Efficient and Stable Normal Perovskite Solar Cells |
| title_sort | low cost and lithium free hole transport layer for efficient and stable normal perovskite solar cells |
| topic | perovskite solar cell hole transport layer X60 Li-TFSI EMIM-TFSI stability |
| url | https://www.mdpi.com/2079-4991/13/5/883 |
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