How does alkyl chain length modify the properties of triphenylamine-based hole transport materials?

Hole transport materials (HTMs) exhibiting suitable electronic properties, fast hole transport, high hydrophobicity and good oxygen resistance are critical for realizing perovskite solar cells (PSCs) that are stable and exhibit high-performance. Manipulating the length of alkyl chains is a widely adopted strategy that can fine tune the properties of organic materials in order to enhance their performance for various applications. Yet, a systematic exploration of the influence of chain length on those properties most relevant to highly performing HTMs in PSCs is lacking. Multiscale simulations, along with morphological analyses, uncover relationships between alkyl chain length and HTM properties that provide important insights for the optimization of future organic materials.