Improving the performance of photonic transistor memory devices using conjugated block copolymers as a floating gate

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2021-01, Vol.9 (4), p.1259-1268
• Main Authors: Chen, Yu-Che, Lin, Yan-Cheng, Hsieh, Hui-Ching, Hsu, Li-Che, Yang, Wei-Chen, Isono, Takuya, Satoh, Toshifumi, Chen, Wen-Chang
• Format: Article
• Language: English
• Subjects: Block copolymers; Electrets; Field effect transistors; Memory devices; Morphology; Photonics; Polystyrene resins; Semiconductor devices; Transistors
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d0tc05326k

We report the synthesis, morphology and photo-memory device applications of a block copolymer (BCP) consisting of poly(9,9-dioctylfluorene) (PFO) and polystyrene (PS). Three BCPs were designed with various PS contents to manipulate the structure-performance relationship of the polymer electrets in a photonic field-effect transistor-type (FET) memory device. The memory device using the BCP electret exhibited a dynamic switching behaviour with photo-writing and electrical-erasing processes. We found that the BCPs with a high PS content provided improved device performance, which could be explained by two aspects: (1) the enhanced β-conformation of the PFO strengthened the electron-trapping capability, (2) the well-dispersed and microphase-separated morphology stabilized the trapped electrons on the interface of PFO and PS domains. Consequently, PFO 5k - b -PS 22k outperformed in terms of the photo-responding current along with having a high current on/off ratio of 10 4 and exhibited a retention time of more than 10 000 s. Our experimental results revealed the effectiveness of using the design based on a BCP for application in photonic FET memory devices. We report the synthesis, morphology and photo-memory device applications of a block copolymer (BCP) consisting of poly(9,9-dioctylfluorene) (PFO) and polystyrene (PS).