Transparent wearable monitor gives real-time warnings about overexposure to sunlight

Scientists in South Korea have unveiled a transparent, wearable sensor that monitors a user’s exposure to ultraviolet A (UVA) radiation in real-time. The technology could help prevent sunburn and long-term skin damage that can cause cancer.

Ultraviolet radiation is released naturally by the sun and artificially by tanning beds. The problem with overexposure is that the rays can penetrate deep into the skin and damage DNA, potentially causing cells to grow out of control and leading to cancer. In many countries, the majority of skin cancer cases are linked to this type of overexposure.

While wearing long clothes and hats and applying sunscreen provides valuable protection, the researchers wanted a simple device to alert wearers when exposure reached a certain level. Current sensors often lack the ability to track UVA and are opaque, which makes them uncomfortable and difficult to use in wearable tech like smart glasses.

In their study, published in the journal Science Advances, the researchers describe how they built their sensor layer by layer, starting with a piece of glass. On top of this transparent base, they stacked layers of oxide semiconductors that were also see-through and only reacted to UVA light. For the electrical connections, the team used a transparent indium tin oxide film, ensuring the finished device was nearly invisible and could be easily incorporated into wearables.

To make the sensor a functional monitor, the researchers hooked it up to a small circuit board. This had an amplifier to boost faint UVA signals and a Bluetooth chip to send exposure data straight to a user’s phone.

Successful prototype

The research team tested their prototype extensively in natural sunlight on sunny and cloudy days, and the readings reliably matched professional UV monitoring equipment. Data was wirelessly sent to a user’s phone, where it calculated their accumulated UVA dose and sent a real-time warning when exposure reached 80% of the required amount to cause sunburn.

“This health care device, integrated with a smartphone, demonstrates its potential as a practical approach to prevent risks associated with prolonged UV exposure,” wrote the researchers in their paper.

The device is not yet consumer-ready. Although it has successfully passed laboratory and initial outdoor tests, the team notes that further work is needed before it becomes publicly available. This includes long-term field testing and user studies to confirm the device can survive daily use. The researchers also want to make the entire system smaller so it can be comfortably integrated into wearables such as glasses, smartwatches, and skin patches.

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