Fast Photoresponsive Phototransistor Memory Using Star-Shaped Conjugated Rod-Coil Molecules as a Floating Gate

With the explosive growth in data generation, photomemory capable of multibit data storage is highly desired to enhance the capacity of storage media. To improve the performance of phototransistor memory, an organic-molecule-based electret with an elaborate nanostructure is of great importance because it can enable multibit data storage in a memory device with high stability. In this study, a series of star-shaped rod- coil molecules consisting of perylenediimide (PDI) and biobased solanesol were synthesized in two-armed (PDI-Sol2), four-armed (PDI-Sol4), and six-armed (PDI-Sol6) architectures. Their molecular architecture-morphology relationships were investigated, and phototransistor memory was fabricated and characterized to evaluate the structure- performance relationship of these rod-coil molecules. Accordingly, the memory devices were enabled by photowriting with panchromatic light (405-650 nm) and electrical erasing using a gate bias. The PDI-Sol4-based memory device showed high memory ratios of 10 000 over 10 000 s and a rapid multilevel photoresponse of 50 ms. This achievement is related to the favorable energy-level alignment, isolated nanostructure, and face-on orientation of PDI-Sol4, which eliminated the charge tunneling barrier. The results of this study provide a new strategy for tailoring nanostructures in organic-molecule-based electrets by using a star-shaped rod-coil architecture for high-performance phototransistor memory.

Automated summary

With the increasing amount of data generated, the demand for photomemory capable of multibit data storage has grown rapidly to improve storage capacity. A study focused on developing an organic-molecule-based electret with an elaborate nanostructure to enable multibit data storage in a stable memory device. The researchers synthesized a series of star-shaped rod-coil molecules and investigated their molecular architecture-morphology relationships. They found that the memory devices based on these rod-coil molecules exhibited high memory ratios and rapid multilevel photoresponses, attributed to the favorable energy-level alignment, isolated nanostructure, and face-on orientation of one specific molecule. This study provides a new strategy for designing high-performance phototransistor memory by tailoring nanostructures in organic-molecule-based electrets using a star-shaped rod-coil architecture.