There has been a lot of development put into paper-based circuits in recent years, especially as the demand for disposable, environmentally-friendly electronics has risen. You may have seen, or even used, conductive inks that can be drawn onto paper. But, that ink is still relatively expensive, and it’s not as durable as we’d like. This new development from engineers at Berkeley, however, could alleviate those concerns.
The process that they created can be used to inscribe circuits onto any ordinary sheet of paper in a way that’s both economical and efficient. The element molybdenum is mixed in a gelatin solution, where it bonds with carbon. The solution is then applied to the sheet of paper in a thin coat. After it has dried, a laser is used to heat the paper to 1,000 degrees centigrade in order to create conductive and durable molybdenum carbide traces.
Once the traces have been laser-printed onto the paper, electronic components can be attached as needed. Because the paper still retains its physical properties, it can be folded and bent like origami to affect the circuit. For example, a corner of the paper could be folded over to complete a circuit that connects an LED to a battery, creating a flashlight. Xining Zang, who led the research team, believes this process could be particularly useful for creating disposable medical sensors that are in high demand in developing countries.