A Flexible Integrated System Containing a Microsupercapacitor, a Photodetector, and a Wireless Charging Coil Yang Yue,†,§ Zhichun Yang,†,§ Nishuang Liu,*,† Weijie Liu,† Hui Zhang,† Yanan Ma,† Congxing Yang,† Jun Su,† Luying Li,† Fei Long,‡ Zhengguang Zou,‡ and Yihua Gao*,† †
Center for Nanoscale Characterization and Devices (CNCD), Wuhan National Laboratory for Optoelectronics (WNLO) and School of Physics, Huazhong University of Science and Technology (HUST), Luoyu Road 1037, Wuhan 430074, P.R. China ‡ School of Material Science and Engineering, Guangxi Nonferrous Metals Mineral and Materials, Collaborative Innovation Center, Guilin University of Technology, Jian’gan Road 12, Guilin, Guangxi 541004, P.R. China S Supporting Information *
ABSTRACT: Nowadays, the integrated systems on a plane substrate containing energy harvesting, energy storing, and working units are strongly desired with the fast development of wearable and portable devices. Here, a simple, low cost, and scalable strategy involving ink printing and electrochemical deposition is proposed to fabricate a flexible integrated system on a plane substrate containing an all-solid-state asymmetric microsupercapacitor (MSC), a photoconduct-type photodetector of perovskite nanowires (NWs), and a wireless charging coil. In the asymmetric MSCs, MnO2-PPy and V2O5-PANI composites are used as positive and negative electrodes, respectively. Typical values of energy density in the range of 15−20 mWh cm−3 at power densities of 0.3−2.5 W cm−3 with an operation potential window of 1.6 V are achieved. In the system, the wireless charging coil receives energy from a wireless power transmitter, which then can be stored in the MSC to drive the photoconductive detector of perovskite NWs in sequence. The designed integrated system exhibits a stable photocurrent response comparable with the detector driven by an external power source. This research provides an important routine to fabricate integrated systems. KEYWORDS: ink printing, flexible, asymmetric microsupercapacitor, integration, perovskite nanowires
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easily integrates into other microelectronic devices for power sources. Due to the above advantages, MSCs gained great interest in the field of wearable and portable electronic devices. On the other hand, asymmetric MSCs attract more attention due to their high energy density originating from the larger work function drop between the positive and negative active material.13 Manganese dioxide (MnO2) and vanadium oxides (V2O5) are both suitable for the active materials of MSCs because of their natural abundance, high theoretical capacitance, and multiple oxidation states.14−18 In particular, a larger work function drop between the MnO2 and V2O5 can gain a wider voltage window for fabricated asymmetric MSCs. However, the metal oxides generally show poor electrical conductivity. Therefore, the conductive polymer, mainly including polyaniline (PANI) and polypyrrole (PPy), often combines with metal oxides to increase electrode conductivity,
urrently, the rapid increase in demand of wearable and portable electronic devices makes it essential to develop flexible energy storage devices with small volume, lightweight, and high energy capacity.1 For microelectronic systems, the oversized power source is always problem. To fulfill the requirements of specific wearable and portable applications, an effective strategy is developed for an all-in-one flexible system on one plane substrate,2 which contains energy harvesting, energy storing, and working units. This integrated system converts a variety of ambient energy into useful electrical energy, which then can be stored in energy storage devices to drive microdevices. Because energy storage is crucial to function flexible systems,3,4 microsupercapacitors (MSCs) as the latest energy storage devices have attracted a lot of attention.5−11 Comparing to the traditional sandwich configuration of supercapacitors,12 MSCs usually use two-dimensional interdigital patterns as its conductive path, whose design not only greatly reduces the size of the devices but also exhibits superior charge transfer characteristics because of the minimized internal resistance. In addition, the MSCs possesses long-life, high-power density and © 2016 American Chemical Society
Received: September 19, 2016 Accepted: November 11, 2016 Published: November 11, 2016 11249
DOI: 10.1021/acsnano.6b06326 ACS Nano 2016, 10, 11249−11257
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Figure 1. The schematic diagram and the photographs of printed interdigital template and Au electrode. (a) Schematic illustrating the fabricate process of all-solid-state flexible asymmetric MSCs. (b) Photograph of a printed interdigital template on a flexible PI film. (c) Photograph of the as-prepared Au interdigital electrode. (d) Magnified photograph of the Au interdigital electrode in c).
technology is difficult to fabricate asymmetric MSCs, which limits the applications. Therefore, it is requisite to design a simple, low cost, and high yield way to fabricate asymmetric MSCs. Herein, we proposed a simple, low cost, scalable strategy to fabricate all-solid-state, flexible asymmetric MSCs by using an improved inkjet printing method. Furthermore, the MSCs, combining with photoconductive-type photodetectors of perovskite NWs and wireless charging coil, were integrated into a flexible microcircuit device system at a polyimide (PI) substrate. Briefly, we employed inkjet printing and megnetron sputtering to fabricate a Au interdigital electrode on flexible PI substrates. Then, MnO2-PPy and V2O5-PANI composites were deposited on Au electrodes by electrodeposition as positive and negative electrodes, respectively. The solid-state electrolyte used a gel solution of poly(vinyl alcohol) (PVA) mixed with lithium chloride (LiCl). The as-prepared MSC connected to a wireless charging coil and a photoconductive-type photodetectors of perovskite NWs to fabricate a microelectrical integration system. The wireless charging coil received energy and charges from the MSC, and the MSC drove the photoconductive detector of perovskite NWs in sequence. Benefiting from this structural design, the integrated system had a repeated charging function and a high degree of stability. Over all, this strategy provides a routine for simple and scalable fabrication of wearable and portable integrated electronic devices.
provides an extra capacitance, and effectively prevents erosion of metal oxides in electrolytes.19−22 As usual, a traditional fabrication method of MSCs employs a photolithography technique.23−26 However, the photolithography technique is a high-cost, complex process, and timeconsuming method. It also involves a chemically toxic and environmentally hazardous process. Consequently, it is necessary to develop a simple, scalable, and environmentally friendly strategy in fabricating MSCs. So far, many new methods have been proposed to manufacture MSCs. For instance, a direct laser writing method was applied to fabricate reduced graphene oxide (rGO) MSCs by laser-induced reducing graphene oxide (GO).27 The scalable fabrication of rGO MSCs was achieved by a commercial digital video disk (DVD) laser scribing technique.28 Moreover, 3D porous graphene MSCs were fabricated by laser-induced from a polymer substrate.29 These technologies can only fabricate carbon-based MSCs, which confine the energy density of the devices due to a low specific capacitance and a narrow voltage window of generally
