Development of Simple Hole-transporting Materials for Perovskite Solar Cells

Three low-cost propeller-shaped hole-transporting materials based on a triphenylamine core were investigated in perovskite solar cells. Each hole-transporting material was designed with highly modular side-arms, allowing for different bandgaps while maintaining a consistent binding energy of the highest occupied molecular orbitals in order to facilitate hole-extraction from the perovskite active layer. Perovskite solar cell devices were fabricated with each of the three triphenylamine-based hole-transporting materials and were compared to devices with spiro-OMeTAD and DTS(FBTTh2)2 as the hole-transporting layers. Each of our triphenylamine hole-transporting materials displayed surface morphologies that were considerably rougher than that of spiro-OMeTAD; a factor that may contribute to lower device performance. It was found that using inert, insulating polymers as additives with DTS(FBTTh2)2 reduced the surface roughness, resulting in devices with higher photocurrents. Future studies with triphenylamine-based compounds will be focused on molecular design strategies to enhance solubility, enabling spin-casting of thicker, more planar, films.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author