Hole-transporting material (HTM) is an indispensable constituent in organic electronic devices, generally comprising a donor/dopant combination. We report that a disodium salt of substituted benzo[1,2-b:4,5-b']dipyrrole bearing two racemic alkanediylsulfonate anion side chains (BDPSOs) serves as a neutral, nonhygroscopic, dopant-free HTM for lead perovskite (MAPbI(3)) solar cells. These organic/inorganic hybrid molecules are useful for tunable orbital level and controllable solubility. A fluorinated BDPSO has an energy level matched with MAPbI3, affording an inverted-structure solar cell that performs with 17.2% efficiency with minimal hysteresis. The solar cell devices fabricated using BDPSOs showed remarkable storage and operational stability.
Hexaaryl-benzodipyrroles: Properties and Application as Amorphous Carrier-Transporting Materials
We have newly synthesized 1,2,3,5,6,7-hexaarylbenzo-[1,2-b:4,5-b']dipyrroles (HABDPs) and studied their properties. The HABDPs showed UV absorption maxima at 377-390 nm, indicating their extended pi-conjugation system. They were also found to serve as efficient amorphous materials, featuring high electrochemical and thermal stability with high carrier mobility of up to 10(-3) cm(2)/Vs using the time-of-flight technique. Application of the HABDPs to organic light-emitting diodes resulted in significantly improved performance in driving voltage and efficiency compared with alpha-NPD, a commonly used hole-transporting material.
1. The synthesis and structure of some pyrroloindoles