Solution‐Processed Sterically Hindered Donor–Acceptor Small Molecules as Molecular Floating‐Gates for High‐Efficiency Ambipolar Charge Trapping Memory

Abstract The molecular floating‐gate transistor memories are fabricated by a simple spinning‐coating method using a small‐molecule material spiro[fluorene‐9,7′‐dibenzo[c,h]acridine]‐5′‐one (SFDBAO) as the trapping element. The molecule with donor–acceptor (D–A) structures contains naphthylamine and quinone‐like structures, which can serve as trapping sites for hole and electron integration. Combined with the steric hindrance effect of the molecule itself, the pentacene (PEN)‐based transistor memory device with solution‐processed SFDBAO shows excellent charge‐trapping ability, including high hole trapping efficiency (3.43 × 10 13 cm −2 V −1 s −1 ), fast programming speed (≈1 ms), and ambipolar memory behavior with a large memory window (74.3 V). The optimized device based on the SFDBAO@polystyrene (SFDBAO@PS = 5:1) film exhibits reliable endurance characteristic (>10 3 cycles) and good charge retention (>2 × 10 4 s). These results suggest that the high‐performance ambipolar OFET memory can be achieved through a small‐molecule material by rational molecular design.