A triple helicene based molecular semiconductor characteristic of a fully fused conjugated backbone for perovskite solar cells

Abstract

We herein report a triple helicene based molecular semiconductor (TBPC-611), characteristic of a fully fused conjugated backbone containing multiple pyrrole rings. TBPC-611 can be solution-processed with nonvolatile 4-tert-butylpyridinium bis(trifluoromethanesulfonyl)imide into a morphologically heat-resistant composite thin film which also possesses high electrical conductivity and high hole mobility. These combined quality factors allow for its use as the protective hole-transport layer of PSCs with 22.1%-efficiency which are remarkably stable at 85 °C for 2000 h. Joint experimental and theoretical investigations have uncovered the crucial correlation of the permeation of internal and external gaseous molecules with the thermal decomposition of perovskites, shedding light on durable perovskite optoelectronic devices.