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.