Kenjiro Fukuda1,Steven Rich1,Sixing Xiong1,Masahito Takakuwa1,Takao Someya1,2
RIKEN1,The University of Tokyo2
Kenjiro Fukuda1,Steven Rich1,Sixing Xiong1,Masahito Takakuwa1,Takao Someya1,2
RIKEN1,The University of Tokyo2
Softness, stretchability, and flexibility are important parameters for the realization of bioelectronics that are compatible with biological curvilinear surfaces having low Young's moduli. Soft and self-powerd electronic devices using soft organic materials will accelerate their realization of bioelectronics such as long-term monitoring of biological signals.<br/>In this talk, we will discuss cutting-edge strategies using organic semiconductor materials to build ultra-flexible and self-powered electronics for bioelectronic applications. As an energy harvesting technology, we are proceeding with efforts focusing on ultra-flexible organic solar cells. Taking advantage of compatibility with ultraflexible, or more specifically, 1-µm-thick film, the total device thickness of organic solar cells including the substrate and the passivation can be down to 5 µm or less. An ultraflexible organic solar cell achieves an power conversion efficiency of 15% under simulated sunlight conditions<sup>1</sup>, which is close to that of a rigid organic solar cell. Benefiting from its thinness, the amount of electricity generated per unit weight reaches 30 W g<sup>-1</sup>. We are developing strategies to minimize thermal and atmospheric degradation of such ultraflexible organic solar cells aiming practical appilcations used in ambient environments<sup>2</sup><sup>3</sup>. In addition, the application of biosensors that use such solar cells as a power source has also been achieved. Since the power sources are directly connected to sensors, such self-powered sensor systems achieved a high signal to noise ratio<sup>4</sup><sup>5</sup>. We will also discuss how to implement it on curved surfaces and strategies for integrating multiple ultra-thin devices.<br/>1. Qin, F. <i>et al.</i> Robust metal ion-chelated polymer interfacial layer for ultraflexible non-fullerene organic solar cells. <i>Nat. Commun.</i> <b>11</b>, 4508 (2020).<br/>2. Jiang, Z. <i>et al.</i> <i>Proc. Natl. Acad. Sci.</i> <b>117</b>, 6391–6397 (2020).<br/>3. Xu, X. <i>et al.</i> <i>Proc. Natl. Acad. Sci.</i> <b>115</b>, 4589–4594 (2018).<br/>4. Park, S. <i>et al.</i> <i>Nature</i> <b>561</b>, 516–521 (2018).<br/>5. Jinno, H. <i>et al.</i> <i>Nat. Commun.</i> <b>12</b>, 2234 (2021).