Sustained Flexible Photonic Transistor Memories Based on Fully Natural Floating Gate Electrets

Chun-Kai Chen; Jin-Chieh Ho; Chih-Chien Hung; Wei-Cheng Chen; Toshifumi Satoh; Wen-Chang Chen

doi:10.1021/acsami.3c05981

Sustained Flexible Photonic Transistor Memories Based on Fully Natural Floating Gate Electrets

ACS Appl Mater Interfaces. 2023 Jul 19;15(28):33829-33837. doi: 10.1021/acsami.3c05981. Epub 2023 Jul 10.

Authors

Chun-Kai Chen^{1

2}, Jin-Chieh Ho^{1

2}, Chih-Chien Hung^{1

2}, Wei-Cheng Chen^{1

2}, Toshifumi Satoh³, Wen-Chang Chen^{1

2}

Affiliations

¹ Department of Chemical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
² Advanced Research Center for Green Materials Science and Technology, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
³ Faculty of Engineering, Hokkaido University, N13W8, Kita-ku, Sapporo 060-8628, Japan.

PMID: 37428837
DOI: 10.1021/acsami.3c05981

Abstract

Photonic transistor memory with high-speed communication and energy-saving capabilities has emerged as a new data storage technology. However, most floating-gate electrets are composed of quantum dots derived from petroleum or metals, which are either toxic or harmful to the environment. In this study, an environmentally friendly floating-gate electret made entirely from biomass-derived materials was designed for photonic memories. The results show that the photosensitive hemin and its derivative protoporphyrin IX (PPIX) were successfully embedded in a polylactic acid (PLA) matrix. Correspondingly, their disparate photochemistry and core structure strongly affected the photosensitivity and charge-trapping capacity of the prepared electrets. With an appropriate energy-level alignment, the interlayer exciton formed with the correct alignment of energy levels within the PPIX/PLA electret. In addition, the demetallized core offered a unique relaxation dynamic and additional trapping sites to consolidate the charges. Correspondingly, the as-prepared device exhibited a memory ratio of up to 2.5 × 10⁷ with photo-writing-electrical-erasing characteristics. Conversely, hemin demonstrated self-charge transfer during relaxation, making it challenging for the device to store the charges and exhibit a photorecovery behavior. Furthermore, the effect of trapping site discreteness on memory performance was also investigated. The photoactive components were effectively distributed due to the high dipole-dipole interaction between the PLA matrix and PPIX, resulting in a sustained memory performance for at least 10⁴ s after light removal. The photonic memory was also realized on a bio-derived dielectric flexible substrate. Accordingly, a reliable photorecording behavior was observed, wherein, even after 1000 cycles of bending under a 5 mm bending radius, the data was retained for more than 10⁴ s. To our knowledge, it is the first time that a two-pronged approach has been used to improve the performance of photonic memories while addressing the issue of sustainability with a biodegradable electret made entirely from natural materials.

Keywords: degradable; hemin; photonic memory; polylactic; porphyrin.