How to turn house lights into energy for smart devices

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In a world where smart devices are becoming a staple in our homes, from Wi-Fi security systems to high-tech toilets, the challenge of keeping these devices powered has led to a tangle of cords and a constant need for battery replacements.

But what if there was a way to harness the power of light inside our homes to keep these devices running?

Researchers have made a significant breakthrough in this direction, exploring how solar panel technology, traditionally used outdoors, can now be adapted to power devices indoors.

Sunlight is a powerhouse of energy, containing a mix of ultraviolet, infrared, and visible light. Solar panels designed for outdoor use are optimized to convert this rich light spectrum into electricity.

However, indoor light is different. It’s generally dimmer and comes from a narrower spectrum, mainly visible light.

This difference poses a unique challenge: can we develop solar panels that work efficiently under indoor lighting conditions?

A team led by Uli Würfel took on this challenge.

They tested different types of photovoltaic (PV) systems – devices that convert light into electricity – to see which ones work best under indoor lighting, particularly under cool white LED lights, a common type of indoor lighting.

The researchers compared eight types of PV devices. These ranged from traditional amorphous silicon panels to newer thin-film technologies like dye-sensitized solar cells.

They measured how well each material converted light into electricity, first under simulated sunlight and then under cool white LED lights.

One material stood out under indoor light: Gallium Indium Phosphide (GaInP). This PV cell showed remarkable efficiency, converting nearly 40% of indoor light energy into electricity.

However, under sunlight, its performance was only modest due to its large band gap, a feature that determines how a material absorbs light to generate electricity.

In contrast, Crystalline Silicon, excellent under sunlight, showed only average performance under indoor lighting. This finding highlights a critical point: materials that are great at converting sunlight aren’t necessarily as effective indoors.

GaInP isn’t currently used in commercially available solar panels. This study points to its potential for indoor applications.

However, there’s a catch. GaInP is expensive, which might limit its use in mass-produced smart home systems.

Perovskite minerals and organic film PV cells emerge as more affordable alternatives. These materials are less expensive and remain stable under indoor lighting.

They don’t reach the high efficiency of GaInP, but their lower cost and stability make them promising for widespread use in powering indoor devices.

An interesting finding from the study is that part of the energy from indoor lights turns into heat instead of electricity.

This insight is crucial for future development. It means there’s room to improve how these PV systems convert light into power, making them more efficient for indoor use.

The exploration of solar technology for indoor use marks an exciting step toward more sustainable and convenient power solutions for smart home systems.

As research continues, we can expect advancements in materials and technologies that will make indoor solar power more efficient, affordable, and practical, lighting up our smart homes in an eco-friendly way.