Novel hole transporting materials based on cyclopentadithiophene for perovskite solar cells

• Published in: Journal of photochemistry and photobiology 2023-08, Vol.16, p.100189, Article 100189
• Main Authors: Lin, Ying-Sheng, Chen, Nai-Hwa, Chen, Yi-Ru, Kalidass, Kollimalayan, Cheng, Hsiu-Yao, Venkatakrishnan, Parthasarathy, Chow, Tahsin J., Chang, Yuan Jay
• Format: Article
• Language: English
• Subjects: 4H-cyclopenta[2,1-b:3,4-b']dithiophene derivative; Hole transport materials; Imine HTMs; Perovskite solar cell
• ISSN: 2666-4690; 2666-4690
• DOI: 10.1016/j.jpap.2023.100189

•D–A–D type hole-transporting materials with cyclopentadithiophene (CPT) as the core structure in n-i-p PSCs.•LY-1 and Pb2+ produced intermolecular attraction, and LY-1 had a good passivation for perovskite layer.•A SnO2 ETL with LY-1 HTM showed the best PCE of 19.12%. We have demonstrated three LY-HTMs for perovskite solar cells in this report. These LY-HTMs embed cyclopentadithiophene (CPT) core that incorporates 2∼4 triphenylamine electron donor units. Designing LY-HTMs with Lewis-basic property of carbonyl or imine, can effectively passivate the defects of insufficiently coordinated Pb2+ in the perovskite layer. The LY-HTMs have good thermal stability and enhanced intermolecular interaction, thereby dense packing, due to the sulfur-sulfur interaction in the dithiophene structure. Moreover, the sulfur-sulfur interaction achieves a deeper HOMO energy level that can be well-matched to perovskite solar cells (PSCs). It also improves the charge mobility to enhance Voc and Jsc values. The best performance using LY-1 as a HTM in PSCs exhibited a Jsc of 23.1 mA∙cm−2, a Voc of 1.06 V, and a fill factor of 0.78, corresponding to an overall conversion efficiency of 19.12% (the control device of spiro-OMeTAD, 17.69%). In addition, the PCEs of the LY-1 PSC devices underwent decays of only 90% and 74.8% of their original values after 10 and 30 days, respectively, under an Ar atmosphere. [Display omitted]