Transparent electrodes refer to oxide degenerate semiconductor electrodes that possess a high level of light transmittance (more than 85 percent) in the visible light spectrum, and low resistivity (less than 1×10-3 Ω-㎝) at the same time. Transparent electrodes are key materials in the IT industry, used in flat displays, photovoltaics, touch panels, and transparent transistors, which need light transmission and current injection/output simultaneously. Up until now, sputtered ITOs (SnO2-doped In2O3) have been widely used.
Recently with the remarkable development in flexible photoelectronic technologies, such as flexible displays, photovoltaics and electric devices, more attention is being put on flexible transparent electrode technology, which can be produced on a flexible substrate rather than the conventional glass substrate. ITO tends to be vulnerable to the substrate’s bending, and thus CNT-, graphene-, and silver-based transparent electrodes as well as polymer transparent electrodes are suggested to replace the ITO.
The usage of transparent electrodes vary: they are used as electrode materials for LCDs, OLEDs, PDPs and transparent displays, while they are used as touch sensors for resistive and capacitive touch panels. They are also used as electrodes for a-Si, CIGS, CdTe, and DSSC photovoltaics.
Displaybank published the “Transparent Electrode Technology Trends and Market Forecast 2013” report. It covers the technological developments related to transparent electrodes and business activities as well as its market forecast up to 2020.
The overall transparent electrode market is forecast to grow to $5.1 billion by 2020, from $1.9 billion in 2012. By market size, display and touch sensor markets are deemed to be the largest. In the display segment, the flexible display will expand to make up 11 percent in 2019, thereby making way for transparent electrodes to replace the ITO and oxide transparent electrodes. In 2020, the oxide transparent electrode is forecast to make up 8 percent of the total market, and silver-based materials or carbon nanotubes will most likely be the strong candidates.
In terms of production cost, the touch sensor market is the best for the transparent electrode to enter, particularly compared to the display market. But the next generation transparent electrode applied to touch sensors will not reach 10 percent of the total market until 2020. It is because the alternative to the ITO must have the same level of properties as the ITO at low production cost. Strategic collaboration with major brands will be inevitably required. Currently, there is no next generation electrode that can perform on a similar level as the ITO and that is able to be mass produced. But if the flexible display market opens up earlier than expected, next generation transparent electrodes will likely replace ITOs at a faster rate.