A Real‐Time Wearable UV‐Radiation Monitor based on a High‐Performance p‐CuZnS/n‐TiO₂ Photodetector

Abstract

Solar radiation, especially ultraviolet (UV) light, is a major hazard for most skin-related cancers. The growing needs for wearable health monitoring systems call for a high-performance real-time UV sensor to prevent skin diseases caused by excess UV exposure. To this end, here a novel self-powered p-CuZnS/n-TiO UV photodetector (PD) with high performance is successfully developed (responsivity of 2.54 mA W at 0 V toward 300 nm). Moreover, by effectively replacing the Ti foil with a thin Ti wire for the anodization process, the conventional planar rigid device is artfully turned into a fiber-shaped flexible and wearable one. The fiber-shaped device shows an outstanding responsivity of 640 A W , external quantum efficiency of 2.3 × 10 %, and photocurrent of ≈4 mA at 3 V, exceeding those of most current UV PDs. Its ultrahigh photocurrent enables it to be easily integrated with commercial electronics to function as a real-time monitor system. Thus, the first real-time wearable UV radiation sensor that reads out ambient UV power density and transmits data to smart phones via wifi is demonstrated. This work not only presents a promising wearable health monitor, but also provides a general strategy for designing and fabricating smart wearable electronic devices.

Tunable self‐powered n‐SrTiO3 photodetectors based on varying CuS‐ZnS nanocomposite film (p‐CuZnS, p‐CuS, and n‐ZnS)

“…In addition, this CZS composite film can be grown in situ on various substrates (quartz, silicon, etc.) or other semiconductor materials to construct heterojunctions via facile solution process …”

“…or other semiconductor materials to construct heterojunctions via facile solution process. [37][38][39] Figure 2A demonstrates the X-ray diffraction (XRD) pattern of the STO crystal film. The diffraction peak for the STO crystal appearing at 22.8 and 46.5 are assigned to (100) and (200) crystal planes of cubic strontium titanate (JCPDF no.…”

“…Xu et al fabricated the p‐CuS‐ZnS (p‐CZS)/n‐ZnO UV photodiode with a good rectifying characteristics and a self‐powered feature, which showed stable and fast photoresponse . Meanwhile, we demonstrated the successful fabrication of a novel wearable self‐powered p‐CZS/n‐TiO 2 UV device with high performance . The fiber‐shaped device shows an outstanding responsivity and high photocurrent.…”

“…38 Meanwhile, we demonstrated the successful fabrication of a novel wearable self-powered p-CZS/n-TiO 2 UV device with high performance. 39 The fiber-shaped device shows an outstanding responsivity and high photocurrent. The asfabricated real-time wearable UV radiation sensor can read out ambient UV power density and transmits data to smart phones via wifi.…”

A Fully Transparent, Flexible, Sensitive, and Visible‐Blind Ultraviolet Sensor Based on Carbon Nanotube–Graphene Hybrid

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generates free-radical chemical species that cause various skin diseases such as inflammatory disorders, aging, and skin cancer. [3][4][5] However, Si-based UV sensors, the most established commercial sensors, are unsuitable for use in such applications because of their lack of mechanical flexibility and optical transparency and their need for high operating voltage and a long-pass filter to block low energy photons. [3][4][5] However, Si-based UV sensors, the most established commercial sensors, are unsuitable for use in such applications because of their lack of mechanical flexibility and optical transparency and their need for high operating voltage and a long-pass filter to block low energy photons.

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