Novel Hole Transport Material Having an Ethylenedioxythiophene Core

H101 having a 3,4-ethylenedioxythiophene core is a novel hole transport material (HTM) for perovskite solar cells which have been receiving much attention as new photovoltaics. H101 can be synthesized by a simple pathway, which is an advantage of H101 compared with the spirobifluorene-based spiro-OMeTAD, a conventional HTM. In 2014, it was reported that solar cell devices consisted of a CH₃NH₃PbI₃ perovskite material and a H101 HTM showed a power conversion efficiency (PCE) of 10.6% without any dopant and 13.2% with doping by tris(2-(1H-pyrazol-1-yl)pyridine)cobalt(III) (FK102). The performance was comparable with that of the spiro-OMeTAD based device (13.7%). A stability test under heat treatment at 70 °C for 7 days indicated that the H101 based devices had thermal stability as high as that of the spiro-OMeTAD devices.