Concept of Photoactive Invisible Inks toward Ultralow‐Cost Fabrication of Transistor Photomemories

Abstract

Abstract Finding the outperforming photoactive charge trapping materials for a new‐trending transistor photomemory application is labor intensive, costly reagents and solvents, and not to mention, inefficient energy and time consumption. In this work, costless organic‐based inks are introduced as a novel photoactive charge storage material that is inspired by high fluorescent ink of cheap invisible pens when exposed to ultraviolet light. The pure powder inks of invisible pens with bright red and greenish‐yellow emission are selected. The estimated usage costs about $0.003 cm−2, confirming its ultralow‐budget material. The pentacene‐based organic field‐effect transistor memory scheme is employed to evaluate the memory behaviors. These invisible‐ink‐based charge storage layers endow a transistor memory device with photoinduced recovery. Interestingly, by conducting the photoassisted operation on the same device, its threshold voltage shifts toward more positive direction, resulting in broaden memory window and faster device operations. On top of that, invisible‐ink‐based transistor photomemory demonstrates the well‐defined and feasible multibit memory cell for the next‐generation storage media. As a result, the employment of commercial invisible inks as a cheapest photoactive charge trapping material can favor the advancement of transistor photomemory devices and related functional applications.

Keywords

• device mechanism
• fluorescent dyes
• low cost
• photonic memory
• photorecovery