Nonvolatile C₆₀ Self-Assembled Monolayer-Induced Photomemory Elements in Pentacene Organic Memory Field Effect Transistors

We have developed a nonvolatile pentacene/C60 self-assembled monolayer (SAM) organic field effect transistor (OFET) memory device that operates with a high on/off current ratio of 105, leveraging an electric field-induced charge transfer for data storage. We also have successfully demonstrated a novel nonvolatile OFET photomemory utilizing pentacene and a C60 self-assembled monolayer (SAM), initially reaching 107 before stabilizing at 103. This highlights its effective charge retention and emission, varying with light exposure, underscoring the C60 SAM's pivotal role in modulating device performance across different lighting conditions. This high ratio is achieved through an electric field-induced charge transfer mechanism, wherein application of a gate voltage causes electrons to move from pentacene to the C60 SAM, effectively changing the device's conductive state. Additionally, the device showcases a unique photoresponsive behavior, where illumination not only augments electron transfer but also introduces complexities such as an increased off current due to the low recombination rate of electrons and holes. Despite this challenge, the ability to control memory states through both electrical and optical means marks a significant step forward, as it paves the way for multifunctional, energy-efficient memory devices.