Volatility Transition from Short-Term to Long-Term Photonic Transistor Memory by Using Smectic Liquid Crystalline Molecules as a Floating Gate

Li, Guan-SyuanGuan-SyuanLiHung, Chih-ChienChih-ChienHungChiang, Yun-ChiYun-ChiChiangLin, Yan-ChengYan-ChengLinYang, Yun-FangYun-FangYangYang, Wei-ChenWei-ChenYangYen, Hao-ChiHao-ChiYenChen, Chun-KaiChun-KaiChenHsu, Li-CheLi-CheHsuWEN-CHANG CHEN2022-03-222022-03-2220212199160Xhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-85118490593&doi=10.1002%2faelm.202101123&partnerID=40&md5=fbbe65af8979d6a8ae17575026d42d00https://scholars.lib.ntu.edu.tw/handle/123456789/598259Rod-like molecules with liquid crystalline phase transitions show highly ordered stacking and orientation, which is promising as the floating gate electret in high-performance photonic field-effect transistor (FET) memory. In this work, a series of rod-like molecules, alkyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (Cn-DNTT), are investigated with a smectic liquid crystalline phase transition. The photonic FET memory featuring these rod-like molecules is correlated with their morphology and crystallographic properties. A volatility transition from short?term to long?term memory behavior is found by utilizing the smectic liquid crystalline phase transitions (SmX, X = H, K, E) to orient the stacking in the floating gate. Accordingly, the annealed 2,9-didecyldinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (C10-DNTT) polycrystalline film with the optimized alkyl chain length achieved preferential end-on orientation associated with the herringbone-type stacking to store charges during photowriting, along with effective charge tunneling for the trapped charges during electrical erasing. Therefore, the resultant photonic FET memory provided a superior ON/OFF current ratio of up to 105 with retention of 104 after 104 s. The results demonstrate that rod-like molecules with smectic liquid crystalline phase and highly ordered orientation have great potentials for developing high-performance photonic FET memory. ? 2021 Wiley-VCH GmbHliquid crystalsphotomemoryrod-like moleculessmectic mesophasetransistor-type memoryOrganic field effect transistorsSmectic liquid crystalsThiopheneField-effect transistorFloating gatesLiquid-crystalsPhotomemoryPhotonic fieldsRod-like moleculeSmectic liquid crystallineSmectic mesophasesTransistor typesTransistor-type memoryMoleculesVolatility Transition from Short-Term to Long-Term Photonic Transistor Memory by Using Smectic Liquid Crystalline Molecules as a Floating Gatejournal article10.1002/aelm.2021011232-s2.0-85118490593