The prospect of a paper-thin computer tablet you could fold up like a newspaper is getting closer, according to a study from a Singapore university.
A review paper from researchers at Nanyang Technological University, published in Science and Technology of Advanced Materials journal, says such flexible electronics are moving closer to reality.
Paper that is transparent and conducts electricity could have widespread applications, including foldable computers, transparent touchscreens and even digital camouflage clothing.
"With widespread and intensive efforts, low-cost and light-weight 'green' electronics fabricated on transparent nano paper substrate will provide new technologies impacting our daily life," say authors.
Cellulose, the key component in paper manufacture, is an alternative to the plastic, glass and silicon that currently make up most electronic devices, including computers and smartphones. After 30 years of research, progress has been made to manipulate the smallest plant fibres - called 'nanocellulose' - for use in electronics.
At NTU, researchers have made 'nanopaper' from nanocellulose and silver nanowires, and found it still conducted electricity after being folded in half 500 times. Some nanopapers have reached 90 per cent transparency, while others are in the 80 per cent range, similar to plastic.
However, nanopapers degrade quickly, and will fully degrade in a month if metal electrodes are removed and the substrate is buried in soil. Work is continuing to find out how to treat nanopapers that contain non-biodegradable materials such as epoxy to maintain their recyclability.
And while the hydrophilic properties of cellulose make it easy to degrade, this needs to be controlled during their operational life. Currently, it is more expensive to produce pure nanopaper than glass or plastic, but a high-speed 'roll to roll' printing used in electronic manufacturing can be adapted for nanocellulose.
Authors Shaohui Li and Pooi See Lee are optimistic that if these issues can be addressed, a wide range of electronics could soon be built from plants. More information from Leeat NTU's School of Materials Science and Engineering, firstname.lastname@example.org