Behaviour of one-step spray-coated carbon nanotube supercapacitor in ambient light harvester circuit with printed organic solar cell and electrochromic display

Abstract

A printed energy harvesting and storage circuit powered by ambient office lighting and its use to power a printed display is reported. The autonomous device is composed of three printed electronic components: an organic photovoltaic module, a carbon-nanotubes-only supercapacitor and an electrochromic display element. Components are fabricated from safe and environmentally friendly materials, and have been fabricated using solution processing methods, which translate into low-cost and high-throughput manufacturing. A supercapacitor made of spray-coated carbon nanotube based ink and aqueous NaCl electrolyte was charged using a printed organic photovoltaic module exposed to office lighting conditions. The supercapacitor charging rate, self-discharge rate and display operation were studied in detail. The supercapacitor self-discharge rate was found to depend on the charging rate. The fully charged supercapacitor was used as a power source to run the electrochromic display over 50 times.

Pyramid‐Textured Antireflective Silicon Surface In Graphene Oxide/Single‐Wall Carbon Nanotube–Silicon Heterojunction Solar Cells

“…In this report, a floating transfer approach is used to form the GOCNT/Si heterojunction in order to form an intimate contact between the GOCNT electrode and the nanotextured Si ( Figure a ) to ensure efficient separation of excitons (Figure b,c). Compared to other liquid processing approaches (including spray coating, spin coating, Mayer rod coating and electrophoretic deposition), the floating transfer has several benefits: 1) room temperature processing; 2) compatibility with almost any substrate; 3) compatibility with surfaces with fine structures; 4) compatibility with most liquid CNT film doping processes; and 5) fabrication of large size hole‐free films. However, the biggest drawback of the floating transfer process is the difficulty in preparation of ultrathin films ( T > 90%) because of the significantly reduced mechanical properties for thin films.…”

Carbon‐Based Functional Materials Derived from Waste for Water Remediation and Energy Storage

“…For practical applications, the leakage current and self‐discharge are very important parameters for characterizing the stability of supercapacitors and batteries to maintain the voltage in an open circuit . Although supercapacitors slowly lose their charge, impurities in the electrode material (or electrolyte) may accelerate the self‐discharge process . Particularly, the ash content, which is considered to be one type of impurity in the traditional AC‐based electrode, has been reported to increase the leakage current .…”

Theoretical analysis and characterization of the energy conversion and storage efficiency of photo-supercapacitors

“…They can be particularly useful as independent energy sources to power autonomous devices such as wearables and Internet of Things nodes [1][2][3], or to act as buffers to mitigate the effects of solar light fluctuations on energy generation [4,5]. One of the main advantages of PSC is their simplicity (only two elements), as they do not need interfacing electronics between the solar cell and the supercapacitor, thus offering a lot of flexibility in their design and fabrication [6].…”

“…PSC can be fabricated as a single stack where the generation and storage components share a common electrode, which considerably reduces resistive losses and minimizes footprint [7]. They can also be fabricated in specific formats, like a fiber [8], or using low-cost solution processing techniques compatible with flexible substrates [1,2,9].…”