Spiro‐Phenylpyrazole‐9,9′‐Thioxanthene Analogues as Hole‐Transporting Materials for Efficient Planar Perovskite Solar Cells

Journal Article · Fri Jun 09 00:00:00 EDT 2017 · Advanced Energy Materials

DOI:https://doi.org/10.1002/aenm.201700823· OSTI ID:1399053

Wang, Yang ^[1]; Zhu, Zonglong ^[2]; Chueh, Chu‐Chen ^[2]; Jen, Alex K. ‐Y. ^[3]; Chi, Yun  ^[1]

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1. Department of Chemistry and Low Carbon Energy Research Center National Tsing Hua University Hsinchu 30013 Taiwan
2. Department of Materials Science and Engineering and Department of Chemistry University of Washington Seattle WA 98195‐2120 USA
3. Department of Materials Science and Engineering and Department of Chemistry University of Washington Seattle WA 98195‐2120 USA, Department of Biology and Chemistry City University of Hong Kong Kowloon 999077 Hong Kong

Abstract Perovskite solar cells have emerged as a promising technique for low‐cost, light weight, and highly efficient photovoltaics. However, they still largely rely on 2,2′,7,7′‐tetrakis( N , N ‐di‐ p ‐methoxyphenylamine)‐9,9′‐spirobifluorene (Spiro‐OMeTAD) to serve as hole‐transporting materials (HTMs). Here, a series of HTMs with small molecular weight is designed, which are constructed on a spiro core involving phenylpyrazole and a second heteroaromatics, i.e., xanthene (O atom), thioxanthene (S atom), and acridine (N atom). Through varying from phenylpyrazole substituted xanthene ( PPyra‐XA ), thioxanthene ( PPyra‐TXA ), to acridine ( PPyra‐ACD ), their optical and electrochemical properties, hole mobilities, and the photovoltaic performance are optimized. As a consequence, PPyra‐TXA based device exhibits the highest power conversion efficiency (PCE) of 18.06%, outperforming that of Spiro‐OMeTAD (16.15%), which could be attributed to the enhancement of hole mobility exerted by the thioxanthene. In addition, the dopant‐free device shows PCE of 11.7%. These results open a new direction for designing spiro‐HTMs by simple modification of chemical structures.

• Sponsoring Organization: USDOE
• Grant/Contract Number: DE‐EE0006710
• OSTI ID: 1399053
• Journal Information: Advanced Energy Materials, Journal Name: Advanced Energy Materials Vol. 7 Journal Issue: 19; ISSN 1614-6832
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English