Carbazole-based HTMs with fused benzene rings as substituents show a power conversion efficiency exceeding 17% (13.7% for Spiro-OMeTAD under the same conditions).
Perovskite solar cells based on dopant-free PBDT[2F]T have achieved a power conversion efficiency (17.52%), combined with an impressive stability in contrast to that with the doped spiro-OMeTAD as a HTM in ambient atmosphere and even in high humidity.
Two HTMs with triphenylamine and carbazole moieties for planar perovskite solar cells are designed, exhibiting 18.2% power conversion efficiency and better stability.