Toward “green” paper-thin, flexible electronics

 

Wed, 06/10/2015 - 9:15am American Chemical Society A new, environmentally friendly paper that glows could lead to sustainable, roll-up electronics. Image: American Chemical SocietyThe rapid evolution of gadgets has brought us an impressive array of “smart” products from phones to tablets, and now watches and glasses. But they still haven’t broken free from their rigid form. Now scientists are reporting in ACS Applied Materials & Interfaces a new step toward bendable electronics. They have developed the first light-emitting, transparent and flexible paper out of environmentally friendly materials via a simple, suction-filtration method. Technology experts have long predicted the coming age of flexible electronics, and researchers have been working on multiple fronts to reach that goal. But many of the advances rely on petroleum-based plastics and toxic materials. Yu-Zhong Wang, Fei Song and colleagues wanted to seek a “greener” way forward. The researchers developed a thin, clear nanocellulose paper made out of wood flour and infused it with biocompatible quantum dots—tiny, semiconducting crystals—made out of zinc and selenium. The paper glowed at room temperature and could be rolled and unrolled without cracking. Source: American Chemical Society

Toward 'green' paper-thin, flexible electronics

 

Wed, 05/20/2015 - 10:15am A new, environmentally-friendly paper that glows could lead to sustainable, roll-up electronics. Courtesy of American Chemical SocietyThe rapid evolution of gadgets has brought us an impressive array of "smart" products from phones to tablets, and now watches and glasses. But they still haven't broken free from their rigid form. Now, scientists are reporting in the journal ACS Applied Materials & Interfaces a new step toward bendable electronics. They have developed the first light-emitting, transparent and flexible paper out of environmentally friendly materials via a simple, suction-filtration method. Technology experts have long predicted the coming age of flexible electronics, and researchers have been working on multiple fronts to reach that goal. But many of the advances rely on petroleum-based plastics and toxic materials. Yu-Zhong Wang, Fei Song and colleagues wanted to seek a "greener" way forward. The researchers developed a thin, clear nanocellulose paper made out of wood flour and infused it with biocompatible quantum dots—tiny, semiconducting crystals—made out of zinc and selenium. The paper glowed at room temperature and could be rolled and unrolled without cracking. The authors acknowledge funding from the Research Fund for the Doctoral Program of Higher Education of China and the National Natural Science Foundation of China. SOURCE: ACS

Breakthrough in flexible electronics enabled by inorganic-based laser lift-off

 

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This schematic picture shows the flexible crossbar memory developed via the ILLO process.

A research team led by Prof. Keon Jae Lee of KAIST provides an easier methodology to realize high performance flexible electronics by using the Inorganic-based Laser Lift-off (ILLO), which enables nanoscale processes for high density flexible devices and high temperature processes that were previously difficult to achieve on plastic substrates.

Flexible electronics have been touted as the next generation in electronics in various areas, ranging from consumer electronics to bio-integrated medical devices. In spite of their merits, insufficient performance of organic materials arising from inherent material properties and processing limitations in scalability have posed big challenges to developing all-in-one flexible electronics systems in which display, processor, memory, and energy devices are integrated. The high temperature processes, essential for high performance electronic devices, have severely restricted the development of flexible electronics because of the fundamental thermal instabilities of polymer materials.

A research team headed by Professor Keon Jae Lee of the Department of Materials Science and Engineering at KAIST provides an easier methodology to realize high performance flexible electronics by using the Inorganic-based Laser Lift-off (ILLO).

The ILLO process involves depositing a laser-reactive exfoliation layer on rigid substrates, and then fabricating ultrathin inorganic electronic devices, e.g., high density crossbar memristive memory on top of the exfoliation layer. By laser irradiation through the back of the substrate, only the ultrathin inorganic device layers are exfoliated from the substrate as a result of the reaction between laser and exfoliation layer, and then subsequently transferred onto any kind of receiver substrate such as plastic, paper, and even fabric.

This ILLO process can enable not only nanoscale processes for high density flexible devices but also the high temperature process that was previously difficult to achieve on plastic substrates. The transferred device successfully demonstrates fully-functional random access memory operation on flexible substrates even under severe bending.

Professor Lee said, "By selecting an optimized set of inorganic exfoliation layer and substrate, a nanoscale process at a high temperature of over 1000 °C can be utilized for high performance flexible electronics. The ILLO process can be applied to diverse flexible electronics, such as driving circuits for displays and inorganic-based energy devices such as battery, solar cell, and self-powered devices that require high temperature processes."

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Story Source:

The above story is based on materials provided by ResearchSEA. Note: Materials may be edited for content and length.

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Journal Reference:

1. Seungjun Kim, Jung Hwan Son, Seung Hyun Lee, Byoung Kuk You, Kwi-Il Park, Hwan Keon Lee, Myunghwan Byun, Keon Jae Lee. Flexible Crossbar-Structured Resistive Memory Arrays on Plastic Substrates via Inorganic-Based Laser Lift-Off. Advanced Materials, 2014; 26 (44): 7480 DOI: 10.1002/adma.201402472

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