Solar power’s incremental steps forward keep coming faster and faster, and not on a single vector: large arrays to power the grid, specific installations where wiring is inefficient or impractical, and for small devices. Cassie Rodenberg, writing at PopularMechanics.com, writes about another step forward with solar power for relatively small devices. From Solar-Powered Circuits Breakthrough – Solar-Powered Circuits Charge by Sunlight in Real-Time:

Researchers at the University of Pennsylvania unveiled the world’s first solar-powered circuit in a January edition of ACS Nano. The technology shows particular promise for touchscreen devices, which could use the circuits as a direct source for sun-power. Not to be confused with solar cells, which convert sunlight energy to electricity and store it for later, this breakthrough involves circuits—electrical devices that provide paths for electricity to flow. This means that sunlight absorbed by the device can immediately use the energy to power the device.

Here’s how the circuit works: Electrons, here known as surface plasmons, oscillate on tiny molecules called nanoparticles. These plasmons act as a ‘super lenses,’ which gather all solar light hitting the circuit. Once the light’s collected, the particles pose as electrodes to ferry away the electricity for a device to use.

Currently, though, researchers can only produce and harness small amounts of energy from the photovoltaic circuits, nowhere near enough to power consumer electronics. But scientists are sure power production will only increase in the future with creative methods like stacking circuits to absorb and focus more light energy.

Self-charging photovoltaic circuitry might be used in display screen pixels or painted on the outside of iPads and smartphones to scavenge sunlight and charge the devices, according to Dawn Bonnell, a researcher on the project. It also could potentially offer just the right power solution for small robotic devices or help computers operate on light alone.

Cassie Rodenberg, Solar-Powered Circuits Breakthrough – Solar-Powered Circuits Charge by Sunlight in Real-Time, at PopularMechanics.com