Technology

To understand the research behind organic thin-film devices plastic conductors needs to be discussed. Lynn’s invention was a technique to make plastic conductors into a thin-film device. Organic compounds such as polymers contain bonds that can be “doped” with halogens which takes the place of “holes” in the bonds with electrons that could then travel throughout the polymer, making it a conductor (The Nobel Prize in Chemistry, 2000: Conductive Polymers). This idea was developed by three different research groups (The Nobel Prize in Chemistry, 2000: Conductive Polymers). The development of the material first began with Alan Heeger and Alan MacDiarmid studying metallic properties of polymers. They then worked together with Hideki Shirokawa, who developed a technique of synthesizing polymers that would be conducive (The Nobel Prize in Chemistry, 2000: Conductive Polymers). After coming together, the group turned to MacDiarmid to dope their polymer with a halogen that supplied the necessary electrons to allow the material to conduct electricity (The Nobel Prize in Chemistry, 2000: Conductive Polymers).

Traditionally solar cells and electrical circuits are made from inorganic materials, such as heavy metals, that are expensive, hurt the environment, and inflexible. However by utilizing the discovery of conducting plastics made by Alan MacDiarmid, Alan Heeger, and Hideki Shirokawa, Loo has “invented an inexpensive, non-toxic and quick process for making organic electronics and plastic circuits” (Chemical Engineer and Biologist Make List of World’s Top Young Innovators). To create these devices she had to understand the methods used to create silicon devices and then interpret that the same technique would be incompatible (Chemical Engineer and Biologist Make List of World’s Top Young Innovators). The techniques used for silicon devices include toxic chemicals that harm the organic material used: silicon processes take up a large amount of time and are made with expensive equipment (Chemical Engineer and Biologist Make List of World’s Top Young Innovators). To create organic devices Lynn had to invent a new technique which became nanotransfer printing. This technique does not use solvents but rather a method similar to stamping (Chemical Engineer and Biologist Make List of World’s Top Young Innovators). These “stamps” are created with grooves on a flexible, viscous, and elastic surface that then print the desired circuit design (Chemical Engineer and Biologist Make List of World’s Top Young Innovators). Then the circuit parts can be placed onto the flexible plastics without the need of chemical etching (Chemical Engineer and Biologist Make List of World’s Top Young Innovators). Advantages unique to this technique include flexibility, large surface areas, cheap memory, and expendable/wearable electronics (Chemical Engineer and Biologist Make List of World’s Top Young Innovators). These organic electronics can be easily incorporated into therapeutics and diagnostic medicine while taking as little as 30 seconds to produce (Chemical Engineer and Biologist Make List of World’s Top Young Innovators).

Thin-film Plastic Electronic Device © Phys.org 2010

Lynn’s invention of nanotransfer printing could only be made with the convenience of many modern inventions, including the discovery of organic conductors made in 2000 which provided a base for her electronic device (The Nobel Prize in Chemistry, 2000: Conductive Polymers). Then a process called spin-coating, which is a technique of applying a compound to a surface and spinning it in order to create a thin film on the base material is used to prepare the plastic surface for gold coating (Video: ‘Plastic Electronics’).  Next a gold evaporator is used to evaporate gold that deposits onto the base material. Lynn developed an alternative process of evaporating gold electrodes on to a silicon rubber stamp, and then laminate the stamp onto the polymer film to make the electronic devices (Video: ‘Plastic Electronics’).