High-performance non-volatile transistor memory devices using charge-transfer supramolecular electrets

We demonstrated high performance non-volatile pentacene based OFET memory devices using charge-transfer (CT) supramolecules of poly(4-vinylpyridine) (P4VP) with two different chromophores, 3-(dicyanomethylidene)indan-1-one (1CN-IN) and 1,3-bis(dicyanomethylidene)indan (2CN-IN), respectively. The intermolecular CT interaction effectively introduced the chromophores as charge trapping sites into the P4VP matrix, leading to a controllable flash-type memory behavior. The electron-trapping ability of the supramolecular electrets was increased with enhancing the chromophore composition in the supramolecules. The experimental molar ratio x of chromophores binding to the repeating unit of P4VP, however, was limited to 0.30 for P4VP(1CN-IN)x or 0.45 for P4VP(2CN-IN)x. The 2CN-IN with one more electron-withdrawing dicyanomethylene group, compared to 1CN-IN, provided a better electron-trapping ability and thus obtained a larger memory window. The device based on P4VP(2CN-IN)0.30 electret exhibited the largest memory window (79 V) with the excellent retention ability of up to 107 s and endurance of over 100 cycles. The study revealed that the CT supramolecular electret could be as a facile and simple approach for future organic memory device applications.