Highly Efficient and High-Brightness White LED Sources

The invention of light-emitting diodes (LEDs) is one of the greatest benefits to mankind. It has significantly contributed to the creation of efficient white-light sources. This opened up new avenues for developing long-lasting and highly-efficient alternatives to older light sources.

In the frame of the €11.8M FP7 IP project “NEWLED” (http://www.newled-fp7.eu), we work on the development of high efficiency and high brightness monolithic and hybrid all-semiconductor white light-emitting GaN-based diodes with high colour rendering index (CRI>95) and efficacies of more than 200 lm/W with the aim to replace conventional light sources with superior highly efficient white LEDs. Dramatic reduction of internal and external losses in III-V semiconductors based LEDs is targeted by clear improvement of crystalline quality and significant enhancement of light extraction along the entire process chain (from semiconductor epitaxial layer growth to the application) to improve the quality of light (CRI) and reduce energy consumption (increase wall-plug efficiency).

To date, the NEWLED consortium has realized a range of high-brightness blue, green, red and multicolour LED chips. The ability of a semi-polar short-period superlattice structure to show emission in the whole visible spectrum has also been demonstrated. The obtained results are enormously encouraging and confirm the great potential of this technology to enable future development of highly efficient superior white LEDs capable of replacing all conventional light sources over the coming years.

Based on the fruitful collaboration between the Partners that allowed gaining the experience in the successful growth of dichromatic nitride LEDs and the theoretical investigations of the optimal ways of colour mixing to get high CRI, the Consortium has successfully realised the White LEDs with CRI of ~98. This important progress in the development of High-CRI white LEDs offers great opportunities for lighting applications that require very accurate colour discrimination.

This work is funded by €11.8M FP7 IP program called NEWLED.