Mitigating Iodine Diffusion by a MoO<sub>3</sub>–Organic Composite Hole Transport Layer for Stable Perovskite Solar Cells
Jisu Hong, Zhaojian Xu, Dominique Lungwitz, J.L. Scott, H. M. Johnson, Yun‐Hi Kim, Antoine Kahn, Barry P. Rand
Abstract
Halide perovskite solar cells (PSCs) exhibit commercialization potential, but long-term stability still must be addressed. Among various products of perovskite decomposition, iodine species are of considerable concern due to their high vapor pressure and corrosive nature. To address this, a small-molecule hole transport layer (HTL), 4,4′,4″-tris[(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), is used; mixing it with molybdenum trioxide (MoO 3 ) p -dopes the layer and slows iodine permeation. We demonstrate that m-MTDATA:MoO 3 HTLs employed in PSCs improve stability under both thermal and voltage bias stress compared to devices with a conventional doped 2,2′,7,7′-tetrakis[ N, N -di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD) HTL.