Alternative Carrier Injection/Extraction Inspired by Electrode Interlayers Based on Peripheral Modification of the Electron-Rich Skeleton

Peripheral modifications of the electron-rich trifluorene-substituted triphenylamine core have been comparatively studied through the linkage of the different polar pendants with fluorene via saturated sp3 hybrid alkyl chains. The work function of electrode could be effectively tuned by the interlayers with or without peripheral pendants of phosphoric acid and phosphonate groups to give selective hole and electron injection/extraction property. Their applications in various vacuum- and solution-processed organic light-emitting diodes and photovoltaic devices were thoroughly investigated. The current comparative study provides valuable exploration on developing high-performance environmentally friendly solvent-processed electrode interlayer materials.