Carbazole-Based Spiro[fluorene-9,9′-xanthene] as an Efficient Hole-Transporting Material for Perovskite Solar Cells
Do Yoon Lee, Gangala Sivakumar, Manju Manju, Rajneesh Misra, Sang Il Seok
Abstract
For the practical application of perovskite solar cells (PSC), it is desirable to have high efficiency, long-term stability, and low manufacturing cost. Therefore, it is required to develop inexpensive and well-performing hole-transporting materials (HTMs). In this study, we synthesized SFXDAnCBZ, which is a new carbazole-based spiro[fluorene-9,9′-xanthene] (SFX) derivative, where the central core and end-cap units consist of SFX and N3,N6-bis(di-4-anisylamino)-9H-carbazole (DAnCBZ), respectively, as an efficient and low-cost HTM for PSCs. Photoluminescence quenching at the SFXDAnCBZ/perovskite interface was more effective than at the perovskite/Spiro-OMeTAD (2,2′,7,7′-tetrakis-(N,N-di-p-methoxy-phenyl-amine) 9,9′spiro-bifluorene) interface. We fabricated a PSC with a power conversion efficiency (PCE) of 20.87% under 1 sun illumination (100 mW cm–2) using SFXDAnCBZ as an HTM. This value is comparable to that measured for the benchmark Spiro-OMeTAD. Thus, this result confirms that SFX core-based materials can be a new kind of HTMs for high-efficiency and low-cost PSCs.