Soluble hexamethyl-substituted subphthalocyanine as a dopant-free hole transport material for planar perovskite solar cells

• Main Authors: Feng Wang, Xiaoyuan Liu, Ehsan Rezaee, Haiquan Shan, Yuxia Zhou, Zong-Xiang Xu
• Format: Article
• Language: English
• Published: The Royal Society 2018-01-01
• Series: Royal Society Open Science
• Subjects: planar perovskite solar cell; hexamethyl-substituted subphthalocyanine; dopant-free hole transport material
• Online Access: https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.180617

Boron subphthalocyanine (SubPc) has special physical and chemical properties, originating from its non-centrosymmetric, near-planar taper structure and large conjugated system; it can act as an alternative to the small molecule hole-transporting material 2,2′,7,7′-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene in perovskite solar cells (PSCs). To achieve a higher solubility in common organic solvents and a more suitable highest occupied molecular orbital energy level that aligns with the valence band of the perovskite material, a SubPc molecule with a hexamethyl substitution at its peripheral position (Me6-SubPc) was successfully designed and synthesized in a one-step method. Completely solution processed PSCs were fabricated with only a small hysteresis, a power conversion efficiency of 6.96% and Voc of 0.986 V.