Versatile Phosphole Derivatives with Photovoltaic, Light-Emitting, and Resistive Memory Properties

A series of dithienophosphole compounds has been successfully synthesized and characterized by photophysical, electrochemical, and thermal studies. Possessing the electron-deficient dithienophosphole oxide moiety, these compounds are found to display strong intramolecular charge transfer character and exhibit high photoluminescence quantum yields of up to 0.68. Taking advantage of the properties, these phosphole-based compounds have been applied as active materials in the fabrication of organic photovoltaics (OPVs), organic light-emitting devices (OLEDs) and organic resistive memory devices. Satisfactory performances with power conversion efficiencies of up to 4.23% for OPV devices, external quantum efficiencies of up to 3.0% for OLEDs, and binary resistive memories with retention time of over 10000 s and distinctive OFF/ON current ratio of 1:107 have been realized based on these dithienophosphole compounds. These findings revealed the multifunctional behavior of these dithienophosphole compounds and represent for the first time the use of phosphole-based small molecules as donor materials for the vacuum-deposited OPV devices.