CbzNaphPPA is self-assembled monolayer (SAM)/multilayer (SAMUL) material serving as hole transport layer in highly efficient organic or perovskite solar cells. It consists of a fused 7H-dibenzo[c,g]carbazole terminal group, a phosphonic acid anchor group, and a rigid phenyl linker to further extend the conjugation of the dibenzo[c,g]carbazole terminal. Compared to 4PADCB, with a higher degree of conjugation and a rigid linker, CbzNaphPPA shows significantly enhanced the intermolecular interaction, leading to the formation of H‑aggregates with better and more densely packed molecular arrays in films. The ordered H-aggregates reduce defects at the perovskite buried interface, suppress non‑radiative recombination, and substantially improve its hole extraction efficiency at the interface.
A champion inverted perovskite solar cell based on CbzNaphPPA SAMUL exhibits a high PCE of 26.07% with an extraordinary FF of 86.45% and excellent operational stability, retaining 94% of its initial PCE after 1200 h of continuous 1 sun illumination under MPP operation at 65 °C.
Serving as hole selective contact for organic solar cells and perovskite solar cells, CbzNaphPPA is an alternative to PEDOT:PSS with superior performance and the convenience of solution deposition at low concentration, i.e. 1 mM.