A spiro-OMeTAD based semiconductor composite with over 100 °C glass transition temperature for durable perovskite solar cells

Albeit the excellent hole extraction yield and conductivity, a doped molecular semiconductor film composed of the state-of-the-art spiro-OMeTAD is so far unqualified for durable perovskite solar cells at 85 °C. We herein blend a commercial polymer poly(9-vinylcarbazole) and a nonvolatile organic salt 4-(tert-butyl)pyridinium bis(trifluromethanesulfonyl)imide with spiro-OMeTAD, yielding a semiconducting composite with high conductivity and high glass transition temperature. The resultant organic composite can be solution-processed into a hole transport layer for 85 °C durable perovskite solar cells with over 21% efficiency, due to good control on charge transport resistance, interfacial recombination resistance, and hole extraction yield. Multiple experimental measurements and molecular dynamics modeling jointly unravel the crucial impact of organic coatings on the thermal decomposition of hybrid perovskites from the split-new perspective of gas diffusion modulation. The blending of poly(9-vinylcarbazole) with high glass transition temperature into the semiconducting composite of commercial molecular semiconductor spiro-OMeTAD and ionic liquid 4-(tert-butyl)pyridinium bis((trifluoromethyl)sulfonyl)amide is found to, not only remarkably stabilize the organic film morphology but also damp the thermal decomposition of organic-inorganic hybrid perovskite, which allows for the fabrication of 85 °C stable, high-efficiency solar cells. [Display omitted] •A nonvolatile, conductive organic composite made from spiro-OMeTAD, PVK, and BPTFSI displays a high glass transition temperature of over 100 °C.•The performance-oriented semiconductor composite can be used for 21%-efficiency perovskite solar cells with good shelf lifetime at 85 °C.•The improved device durability is associated with the improved morphology stability of HTL and the attenuated thermal decomposition of perovskite.