- Green-Solvent-Processable, Dopant-Free Hole-Transporting Materials for Robust and Efficient Perovskite Solar Cells
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In addition to having proper energy levels and high hole mobility (μh) without the use of dopants, hole-transporting materials (HTMs) used in n-i-p-type perovskite solar cells (PSCs) should be processed using green solvents to enable environmentally friendly device fabrication. Although many HTMs have been assessed, due to the limited solubility of HTMs in green solvents, no green-solvent-processable HTM has been reported to date. Here, we report on a green-solvent-processable HTM, an asymmetric D-A polymer (asy-PBTBDT) that exhibits superior solubility even in the green solvent, 2-methylanisole, which is a known food additive. The new HTM is well matched with perovskites in terms of energy levels and attains a high μh (1.13 × 10-3 cm2/(V s)) even without the use of dopants. Using the HTM, we produced robust PSCs with 18.3% efficiency (91% retention after 30 days without encapsulation under 50%-75% relative humidity) without dopants; with dopants (bis(trifluoromethanesulfonyl) imide and tert-butylpyridine, a 20.0% efficiency was achieved. Therefore, it is a first report for a green-solvent-processable hole-transporting polymer, exhibiting the highest efficiencies reported so far for n-i-p devices with and without the dopants.
- Lee, Junwoo,Malekshahi Byranvand, Mahdi,Kang, Gyeongho,Son, Sung Y.,Song, Seulki,Kim, Guan-Woo,Park, Taiho
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- High-performance dye-sensitized solar cells based on 5,6-bis-hexyloxy- benzo[2,1,3]thiadiazole
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New dipolar compounds containing a 5,6-bis-hexyloxy-benzo[2,1,3]thiadiazole entity in the conjugated spacer between the electron donating arylamine and the electron accepting 2-cyanoacrylic acid have been synthesized. These compounds were used as the sensitizers for efficient dye-sensitized solar cells. Compared to the congeners without the hexyloxy chains, the new dyes effectively suppress the dark currents and significantly improve the cell performance. The best conversion efficiency reached ~92% of the N719-based standard DSSC fabricated and measured under similar conditions (AM 1.5 irradiation). The Royal Society of Chemistry 2012.
- Chou, Hsien-Hsin,Chen, Yung-Chung,Huang, Hsuan-Jui,Lee, Ting-Hui,Lin, Jiann T.,Tsai, Chiitang,Chen, Kellen
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p. 10929 - 10938
(2012/08/07)
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