A Dual‐Function Micro‐Swiss‐Roll Device: High‐Power Supercapacitor and Biomolecule Probe
Letícia M. M. Ferro, Leandro Merces, Hongmei Tang, Dmitriy D. Karnaushenko, Daniil Karnaushenko, Oliver G. Schmidt, Minshen Zhu
Abstract
Abstract Tiny autonomous systems less than 1 mm across need small energy storage to satisfy the demand for temporary pulse power and consistent power supply. A battery or supercapacitor alone cannot meet both requirements. Integration of battery and supercapacitor is an alternative, but it introduces a device (supercapacitor) that is not frequently invoked but requires substantial space. Herein, a submillimeter (0.42 mm 2 ) high‐power supercapacitor with an additional function, namely, an on‐chip integrated probe for biomolecule detection is created. The dual‐function device is directly used in the liquid electrolyte, and its Swiss‐roll geometry allows for operation in a minimum 12‐nL electrolyte. The micro‐Swiss‐roll supercapacitor delivers a power density of 911 mW cm −2 and displays a 98% capacitance retention over 10 000 cycles. The biomolecule probe achieves a sensitivity of 230–262 µA m m −1 with a limit of detection of 0.4–0.5 × 10 −3 m for the proof‐of‐concept target, the neurotransmitter dopamine. The biomolecule probe achieves a 230–262 µA m m −1 sensitivity with a limit of detection of 0.4–0.5 × 10 −3 m for the proof‐of‐concept target, the neurotransmitter dopamine, along with selectivity in the presence of ascorbic acid. The independent dual function provides a promising route toward the full‐time use of dust‐sized supercapacitors integrated into submillimeter functional systems.