Skin color-specific and spectrally-selective naked-eye dosimetry of UVA, B and C radiations

Abstract

Spectrally–selective monitoring of ultraviolet radiations (UVR) is of paramount importance across diverse fields, including effective monitoring of excessive solar exposure. Current UV sensors cannot differentiate between UVA, B, and C, each of which has a remarkably different impact on human health. Here we show spectrally selective colorimetric monitoring of UVR by developing a photoelectrochromic ink that consists of a multi-redox polyoxometalate and an e− donor. We combine this ink with simple components such as filter paper and transparency sheets to fabricate low-cost sensors that provide naked-eye monitoring of UVR, even at low doses typically encountered during solar exposure. Importantly, the diverse UV tolerance of different skin colors demands personalized sensors. In this spirit, we demonstrate the customized design of robust real-time solar UV dosimeters to meet the specific need of different skin phototypes. These spectrally–selective UV sensors offer remarkable potential in managing the impact of UVR in our day-to-day life.

UV‐Sensitive Wearable Devices for Colorimetric Monitoring of UV Exposure

“…UV‐sensitive dyes show a promising method for monitoring UV radiation, comparable with other reported approaches . However, most approaches in the literature are based on an evaluation of the colors without a smartphone application.…”

“…However, most approaches in the literature are based on an evaluation of the colors without a smartphone application. One approach used UV dyes applied as smileys on a substrate, which change their smile with increasing exposure . In another approach, the UV sensors were adapted to different skin types.…”

Recent Advances and a Roadmap to Wearable UV Sensor Technologies

“…As different skin phototypes (types I–VI for lighter to consistently darker color) have different levels of UV tolerance, the use of MED needs to be associated with a particular skin type. According to the Fitzpatrick scale,12 the MEDs of UVA and UVB for the six skin types are listed in Table 1 13. The first aspect evident from this scale is that our tolerance to UVA radiation is almost 1000 times higher than for the high‐energy UVB radiation.…”

“…Copyright 2018, The Authors, some rights reserved; exclusive licensee and published by the American Association for the Advancement of Science. Colorimetric sensors: top‐left: Reproduced under the terms and conditions of the CC‐BY license 13. Copyright 2018, The Author(s).…”

“…This process transforms the material from one photostate to another that has a different absorption spectrum, thus leading to a color change that can be potentially captured by the naked eye. The simplicity of the reaction output allows colorimetric detection mechanism to be integrated with a variety of flexible substrates including paper,13,34 polydimethylsiloxane (PDMS),35 polyethylene naphthalate (PEN),36 low‐density polyethylene (LDPE),37 and silicon films38 offering an intrinsic advantage for a direct and simple means to detect UV radiation. Wearable photochromic UV sensors based on such flexible substrates have begun to attract significant research interest.…”