Michael Berger’s June 27, 2024 Nanowerk Spotlight article describes some of the latest work on developing electronic paper devices (yes, paper), Note 1: Links have been removed, Note 2: If you do check out Berger’s article, you will need to click a box confirming you are human,+
Paper-based electronic devices have long been an intriguing prospect for researchers, offering potential advantages in sustainability, cost-effectiveness, and flexibility. However, translating the unique properties of paper into functional electronic components has presented significant challenges. Traditional semiconductor manufacturing processes are incompatible with paper’s thermal sensitivity and porous structure. Previous attempts to create paper-based electronics often resulted in devices with limited functionality or poor durability.
Recent advances in materials science and nanofabrication techniques have opened new avenues for realizing sophisticated electronic devices on paper substrates. Researchers have made progress in developing conductive inks, flexible electrodes, and solution-processable semiconductors that can be applied to paper without compromising its inherent properties. These developments have paved the way for creating paper-based sensors, energy storage devices, and simple circuits.
Despite these advancements, achieving complex electronic functionalities on paper, particularly in areas like neuromorphic computing and security applications, has remained elusive. Neuromorphic devices, which mimic the behavior of biological synapses, typically require precise control of charge transport and storage mechanisms.
Similarly, physically unclonable functions (PUFs) used in security applications depend on the ability to generate random, unique patterns at the nanoscale level. Implementing these sophisticated functionalities on paper substrates has been a persistent challenge due to the material’s inherent variability and limited compatibility with advanced fabrication techniques.
A research team in Korea has now made significant strides in addressing these challenges, developing a versatile paper-based electronic device that demonstrates both neuromorphic and security capabilities. Their work, published in Advanced Materials (“Versatile Papertronics: Photo-Induced Synapse and Security Applications on Papers”), describes a novel approach to creating multifunctional “papertronics” using a combination of solution-processable materials and innovative device architectures.
…
The team showcased the potential of their device by simulating a facial recognition task. Using a simple neural network architecture and the light-responsive properties of their paper-based device, they achieved a recognition accuracy of 91.7% on a standard face database. This impressive performance was achieved with a remarkably low voltage bias of -0.01 V, demonstrating the energy efficiency of the approach. The ability to operate at such low voltages is particularly advantageous for portable and low-power applications.
In addition to its neuromorphic capabilities, the device also showed promise as a physically unclonable function (PUF) for security applications. The researchers leveraged the inherent randomness in the deposition of SnO2 nanoparticles [tin oxide nanoparticles] to create unique electrical characteristics in each device. By fabricating arrays of these devices on paper, they generated security keys that exhibited high levels of randomness and uniqueness.
…
One of the most intriguing aspects of this research is the dual functionality achieved with a single device structure. The ability to serve as both a neuromorphic component and a security element could lead to the development of highly integrated, secure edge computing devices on paper substrates. This convergence of functionalities addresses growing concerns about data privacy and security in Internet of Things (IoT) applications.
…
Berger’s June 27, 2024 Nanowerk Spotlight article offers more detail about the work and it’s written in an accessible fashion. Berger also notes at the end, that there are still a lot of challenges before this work leaves the laboratory.
Here’s a link to and a citation for the paper,
Versatile Papertronics: Photo-Induced Synapse and Security Applications on Papers by Wangmyung Choi, Jihyun Shin, Yeong Jae Kim, Jaehyun Hur, Byung Chul Jang, Hocheon Yoo. Advanced Materials DOI: https://doi.org/10.1002/adma.202312831 First published: 13 June 2024
This paper is behind a paywall.