Grid-Based Small Molecular For High Stable Non-volatile Organic Field-Effect Transistor Memory

Compared with the traditional silicon-based counterparts,non-volatile organic field-effect transistor?OFET?memories have attracted great attention because of their advantages,such as non-destructive reading,excellent flexibility and compatibility,solution processability and low-temperature processing.Among them,the nano-floating-gated OFET memory has controllable and isolated charge storage sites,which is beneficial for achieving high performance memory.Typically,the floating-gates are formed by nanostructured materials such as metal nanoparticles,inorganic semiconducting quantum dots,or small molecules.However,loose polymer electrets are always desired to act as polymer matrix or tunneling dielectrics to smooth the trapping layers,resulting degraded tefficiency of charges trapping and increased operating voltage.Moreover,the deposition process of inorganic nano-floatinggates are formed through precise control of nanoparticle parameters such as size,denisity and distribution.Due to the well-defined molecular and electronic structure,recent studies have reported that solution-processed small molecule materials could act as molecular charge trapping mediums to achieve high density and large capacity OFET memory.Among them,grid-based small molecules are novel wide-bandgap semiconductor materials,which own high potential barrier for retaining trapped charges and can be prepared for high quality thin film by solution method.In this work,the pentacene-based OFET memory with grid-based small molecular G₄?PT-bifluorene ring[4]?is successfully prepared by solution method.The G₄ film has a smooth and uniform film morpholog.The G₄OFET memory exhibits excellent memory performance,with a fast writing speed of 20 ms,a high memory ratio of over 10⁵ after 10⁴ s under hole-trapping mode.The results indicated that grid-based small molecular-floating-gatese are promising charges trapping materials to realize high performance OFET memory.To further improving the electron-trapping performances,the molecular double floating-gates are formed by the blending of p-type G₄ and n-type C₆₀.In addition to the role of p-type charge trapping elements,the G₄ also acts as hybrid matrix to form a smooth blending film.Consequently,the non-volatile OFET memory with molecular double floating-gates demonstrate high performances and stable characteristics,such as a high memory window of 70 V,and current on/off ratio of over 10⁵.Under both hole-trapping and electron-trapping mode,the memory ratios are over 10⁶ and 10⁵ after10⁴ s,respectively.Moreover,the 8-level memory states could be realized.The 8-level storage characteristic can encode and redefine information to achieve information encryption.