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Incumbent vs. emerging technologies explored at the Printed Electronics USA 2012 conference
OLEDs vs. LEDs in lighting applications
The OLED lighting industry is still in its infancy. The price points are several orders of magnitude above those projected by industry roadmaps and even more off cost targets that are required for widespread market uptake. There is still no set of standards or consensus in the industry on optimal device architecture (stack, double layer, etc), manufacturing technique (evaporation, solution processing or hybrid) or manufacturing toolkit. It is not even clear how OLED lighting can borrow from techniques developed and scaled for the OLED display industry.
With cost drivers today such as integrated substrates (encompassing the substrate, the transparent conductor and external light extraction layer), which constitute 45-50% of the overall cost and encapsulation issues, it is not yet clear how and when costs are going to come down to competitive levels when compared to LEDs.
LED technology on the other hand is many years ahead of its OLED counterpart. It was already a $10billion market in 2011. In 2001, there were only 38 manufacturing sites globally; this rose to 169 in 2012. Today, manufacturing takes place mostly in far Asia. Indeed, China, Japan and Taiwan offer 52.2% of the global manufacturing capacity.
Not all however is well with the LED industry. Similar to the photovoltaic industry, the market today is currently experiencing a supply glut (China has heavily subsidised manufacturing capacity). The industry itself has created excess capacity in anticipation of market pull from the LED-LCD industry and in addition to this, the demand is also expected to slow.
Going forward, the most difficult challenge lies in meeting the tough cost targets set by the incumbent technology. The enormity of the challenge can be appreciated when one thinks that LEDs, with all their complexity, will need to be cost competitive with an incandescent lamp that is essentially a simple resistor.
Silicon and thin films solar cells vs. OPVs and DSSCs
Silicon and thin film solar cells, through performance improvements, government incentives in some parts of the world and mass production at high volumes have reached price points that make them very attractive and are currently the favoured technologies when looking at large scale installations such as roof top (residential and commercial) or solar farms.
The advent of 3rd generation, such as organic photovoltaics (OPVs) and dye sensitized solar cells (DSSCs) relates to their potential for reaching even lower costs due to the usage of abundant, low cost materials and simple manufacturing processes along with added functionalities such as lower weight, flexibility, semitransparency etc. These added performance metrics can potentially enable the use of photovoltaics in new applications where rigid conventional cells would be unsuitable. Together with their cost reduction potential they could eventually offer solutions that can allow for further adoption of solar power generation.
Performance limitations in 3rd generation solar cells
The main issues that 3rd generation PV technologies have to solve relate to performance limitations: in lifetime and efficiency. The champion efficiency map in figure 1 (for outdoor lighting conditions), compiled by the National Renewable Energy Laboratory in the USA clearly depicts the handicap in best performance achieved by OPVs and DSSCs when compared to technologies that have been under development for longer and have achieved much better efficiency levels. In OPVs, Heliatek GmbH has demonstrated maximum efficiency of its latest cells at 10.7%. For DSSCs research led by Professor McGehee at Stanford University and published in Nature Photonics in March 2012 has demonstrated record power-conversion efficiency of 12.3%.
On the other hand and on a more positive note, it's also obvious that amorphous Silicon performance is not out of reach anymore and the gap in efficiency has closed dramatically in recent years.
A significant limitation for both OPVs and DSSCs remains the stability of these types of cells, especially when taking advantage of flexible form factors and not depositing on glass. Lifetime in some utilization scenarios is limited to around two years, a significant difference to the 25+ year lifetime guarantee offered by competing technologies. Glass deposited versions can actually achieve lifetimes over 10 years but degradation mechanisms relating to sensitivity to moisture, oxygen and in some cases light itself have posed a barrier in achieving lifetimes that are competitive with incumbent technologies.
Emerging technologies at Printed Electronics USA
Speakers representing all of the above technologies, including GE, Applied Materials, Acuity Brands Lighting, Solarmer, Dyesol and G24 Innovations, sitting in different parts of the value chain will give their perspectives at the conference and will highlight their opinions in the on-going competition between "incumbents and newcomers" and the way companies are moving forward towards successful commercialization.
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