Professor @ Vice-Rector for Research Universidade NOVA de Lisboa, Director CENIMAT - Centre for Materials Research, Professor at Materials Science Department, FCT, Universidade NOVA de Lisboa
TRANSPARENT ELECTRONICS: A MATERIALS REVOLUTION
CENIMAT/i3N, Department of Materials Science, NOVA School of Science and Technology (FCT-NOVA) and CEMOP/UNINOVA, NOVA University Lisbon, Campus de Caparica, 2829-516 Caparica, Portugal; email@example.com
Transparent electronics has gained special attention during the last decade and is today well established as one of the key technologies for a wide range of device applications and is one of the most promising technologies for new electronic products with high added value, away from the traditional silicon technology.
The key components are sustainable abundant and non-toxic materials based on metal oxides (like zinc oxide) of different origins and play an important role, not only as passive components but also as active components, similar to what is observed in conventional semiconductors like silicon. The viability of this technology depends to a large extent on the performance, reproducibility, reliability and cost of the metal oxide based thin film transistors (TFTs). Transistors are the key components in most modern electronic circuits, and are commonly used to amplify or to switch electronic analog and digital signals. The best known application of TFTs is in flat panel displays.
TFTs have been fabricated in a wide variety of materials, but hydrogenated amorphous silicon has been the enabling technology for the active matrix liquid crystal display (AMLCD), common place in portable and desktop computers, high resolution TVs, tablets and smartphones. However, due to low cost of production, low-temperature processing and high resolution, AMLCD technology is gradually shifting towards metal oxide based TFT. Beside higher resolution, one of the advantages of this technology is that it can use existing manufacturing infrastructure which was developed for amorphous-Si TFT. The metal oxide was already adopted by the industry and is based on IGZO (Indium-Galium-Zinc-Oxide) and it was a breakthrough in display technology since it delivers high-resolution, ultra-low power, and slim product profiles, plus exceptionally detailed touch panel capabilities (see Fig. 1). IGZO is a driving force behind new developments in a variety of fields, enabling LCDs, as well as OLED, and MEMS displays, with new levels of performance.
Fig. 1 – Comparison of active matrix backplanes using amorphous silicon with the IGZO technology (Adapted from SHARP).
The first panels incorporating IGZO display technology first appeared in 2012 by Sharp. The following years saw the emergence of televisions and other consumer electronic products such as smartphones and laptops featuring the same innovative display technology. With industry trend and market asking for high definition and power-efficient display panels, IGZO is fast becoming a fitting display technology (see Fig. 2).
Fig. 2 – Some examples of oxide-based TFT commercial products: mobile phones, monitors, tablets, laptops, desktops, TVs and watches.
As it was projected by some forecast reports, transparent electronics market was valued at USD 1000 million in 2019 and is expected to reach USD 3800 million by 2025, at a CAGR of 25% over the forecast period 2020 – 2025. These numbers justify a real need as well as a scientific and social commitment in order to keep/increase the level of development but in a responsible way in terms of our planet in accordance with the green deal. We start it 10 years ago!. Besides that and by adding electronics to the rest of the 95% of objects surrounding us but do not have electronics yet, the market of electronics will growth at least 10 times.