Photophysical, electrochemical and flexible organic resistive switching memory device application of a small molecule: 7,7-bis(hydroxyethylpiperazino) dicyanoquinodimethane

Abstract Utilization of Hydroxyethyl piperazine in a straightforward reaction with tetracyanoquinodimethane (TCNQ) produced a unique multifunctional molecular material 7,7-bis(Hydroxyethyl piperazino)dicyanoquinodimethane (BHEPDQ) exhibiting fluorescence, electrochemical property and capability of organic resistive switching (RS) memory device application. Obtained molecular material has been characterized by various spectroscopic and single crystal X-ray diffraction techniques. Fluorescence decay study in solid revealed single excited state conformation with life time ~1.26 ns. The energy levels were derived from the cyclic voltammetry and the electrochemical band gap was found to be 2.76 eV, good agreement with the theoretical band gap (2.75 eV). Flexible Al/BHEPDQ/ITO/PET RS non-volatile memory device was fabricated and different electrical performances were tested, which demonstrated excellent switching property. The SET/RESET voltage was found to be 2.26 V/– 2.88 V and the device offered high retention without any distortion. The effect of convex (upward bend) and concave (downward bend) bending on the resistive switching behavior of the same device was also investigated. The devices on a flexible platform under the application of a strain through different bending conditions exhibit no degradation on the electrical properties and the obtained results also matched well with the device under no stress, demonstrates its high reliability and ability for practical flexible electronic applications. The memory operations were also explained employing a proposed band diagram and transport studies were explicated to have the better insight of the obtained electrical performances. This work offers a new approach towards the realization of a novel organic material and its integration for efficient flexible memory device applications.