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. Author manuscript; available in PMC: 2019 Feb 4.
Published in final edited form as: Sci Transl Med. 2018 Dec 5;10(470):eaau1643. doi: 10.1126/scitranslmed.aau1643

Fig. 4. mm-NFC dosimeters with dual, independent operation in the UVA and UVB ranges.

Fig. 4.

(A) Photographic image of a dosimeter capable of independent measurements of UVA and UVB, bent between a thumb and index finger. (B) Circuit diagram of the device. The configuration follows that of the UVA dosimeter but using two separate ADCs on a single NFC chip, two SCs (SC1, SC2), two MOSFETs (MOS2), and single GPIO for reset, and separate UVA PD (PD2) and UVB PDs (PD1 × 4). (C) EQE spectrum of a UVB PD (n = 1). (D) Output of the UVB dosimeter channel as a function of total dose of UVB (305 nm) exposure. Measurements show results for dosimeter that incorporate 10 UVB PDs (PDs), 4 PDs, and 1 PD to illustrate the scaling of the response (n = 1). (E) Photocurrent as a function of intensity of UVB (305 nm) exposure for dosimeters with 10 PDs, 4 PDs, and 1 PD (n = 1). (F) System-level leakage current of the dosimeter (n = 1). Measured leakage current is the current to maintain constant voltage. (G) Output voltages from the UVA and UVB channels (n = 1) as a function of time of exposure to a combination of UVA (365 nm) and UVB (305 nm), only UVA, or only UVB. The UVA intensity is 2.2 mW/cm2, and the UVB intensity is 0.16 mW/cm2.