Introduction

Electronic waste, also known as e-waste, comes from electronic products which are damaged or not working, unwanted, or have been fully used to its maximum capacity and are discarded by the owner. The rising problem of electronic waste is a threat to sustainability, due to the use of non-reusable or recyclable materials and chemicals used in electronics (“What Is E-Waste? Definition and Why It’s Important”). In terms of electronic parts, electronics screen and lamps are two of the main contributors to e-waste globally. Screen and LEDs are gaining popular use in recent years, so the significance of the problem is projected to increase as, by 2025, it is estimated that 9 out of 10 light bulbs would consist of LEDs (Science Borealis).

This project attempt to prototype two types of device which one or more if its parts are from biodegradable materials.

1.Electroluminescent Display

An electroluminescent (EL) display is similar to LEDs in which light can emit from the device when voltage is applied. In this work, an EL display is made using barium titanate powder (BaTiO3) and blue luminescent powder painted on indium tin oxide (ITO) coated glass. In this work, we focus our investigation to replacing the ITO coated glass which is inorganic with an organic biodegradable alternatives, PEDOT:PSS on chitosan film, a biopolymer sourced from crab shell.

2.Flex Sensor

A flex sensor is useful in robotic applications and more recently, in flexible display technologies. They are usually made on conventional plastic that does not biodegrade. In this work, we aim to make an alternative biodegradable flex sensors made of PEDOT:PSS on chitosan film. Both are organic materials that biodegrade.

Electrochromic Screen

The electrochromic screen has similar characteristics as LED screens. Indium Tin Oxide (ITO) creates a transparent conductive layer on glass slides, typically used in display technology, solar cells, and organic LEDs. The ITO layer could be substituted with a coat of PEDOT:PSS. On top of the ITO-coated glass slide, wood varnish and barium titanate powder mixed in a ratio of 80.9:19.1 is painted, creating a dielectric layer. After the dielectric layer is completely dried, wood varnish and electroluminescent powder mixed in a ratio of 7:3 are painted, creating an electroluminescent (EL) phosphor layer that emits light. When the EL phosphor layer is 80% dry, another ITO-coated glass is sandwiched with applied pressure until the EL phosphor layer completely dries. The electrochromic screen functions similarly to an LED lamp when connected to a 3-volt power supply.

Biodegradable Electronics

With the arising significance of sustainability, biodegradable electronics would have a significant impact on solving the problems of electronic waste. There are other waste problems other than electronic waste, such as seafood waste, also known as fish waste. Shrimp, krill, crab, and shells are seafood waste that affects surrounding areas and even wider coastal zones (Arvanitoyannis and Kassaveti). As an attempt to solve both problems, chitosan films are projected to be used as the substrate for the making of biodegradable sensors.

Flexible Eletronics: Robotiv Flex Sensor Proof-of-Content

Currently, there are various types of foldable electronic devices in the market, such as Samsung’s Z Fold, Z Flip, and Xiaomi’s Mi Mix Fold. These devices utilizes various flexible electronic components such as flexible display and/or sensors. In our research, we attempted to assess the possibility of creating simple sensors from chitosan coated with PEDOT:PSS. First, we evaluate the performance of PEDOT:PSS as flex sensors by using conventional substrate as the base for proofing the concepts. Then, the flex sensors are further prototyped as robotic flex sensor for detection the movement of human hand to control a robotic hands.

Conclusion and Future Outlook

The applications of PEDOT:PSS were explored on various substrates. As it is, we observed a mismatch between the PEDOT:PSS and the substrates that causes uneven dispersion. In this work, we have discovered simple methods that allow effective applications of PEDOT:PSS on those surfaces. To disperse PEDOT:PSS on ITO coated glass and conventional plastic, a surfactant is required. We have found that a little bit of soap is sufficient and highly effective. Coating a layer of PEDOT:PSS on chitosan films does not dissolve the film, though causes the film to swell. However, a thin coating of oil reduces the amount of swelling. Overall, a firm grasp of building an electrochromic screen and a robotic flex sensor out of glass and conventional plastic has been developed through this research. This research also provides a proof-of-concept that chitosan films coated with PEDOT:PSS may work in replacing e-waste derived from glass and plastic. In the future, more work on decolorization of chitosan films and their thickness control are required, especially for applications as LED screen and flex sensor applications, to imitate the stability and clarity of glass and plastic.

Yoon Lee

PUBLICATION AND PRESENTATION

EVENTS ATTENDED