Application of a Tetra-TPD-Type Hole-Transporting Material Fused by a Troger's Base Core in Perovskite Solar Cells

One of the obstacles to the commercialization of perovskite solar cells (PSCs) is the high price and morphological instability of the most common hole-transporting material (HTM) Spiro-OMeTAD. Herein, a novel HTM, termed V1160, based on four N,N '-bis(3-methylphenyl)-N,N '-diphenylbenzidine (TPD)-type fragments, fused by a Troger's base core, is synthesized and successfully applied in PSCs. Investigation of the optical, thermal, and photoelectrical properties shows that V1160 is a suitable candidate for application as an HTM in PSCs. A promising power conversion efficiency (PCE) of over 18% is demonstrated, which is only slightly lower than that of Spiro-OMeTAD. Moreover, V1160-based devices exhibit improved performances in dopant-free configurations and superior stability. Favorable morphological properties in combination with a simple synthesis make V1160 and related materials promising for HTM applications.