Asymmetrical interface design for unidirectional light extraction from spectrum conversion films.

In this study, we propose a micro-sized photonic structure that extracts 89% of the intrinsic trapped photons from the spectrum conversion film into free space using the Monte-Carlo ray-tracing method. Furthermore, the spectrum of the spectral-shifting film can be accurately simulated based on a mean free path concept, providing the estimation of its overall performance including the external quantum efficiency and the self-absorption efficiency. The simulations show that the spectrum conversion film with micro-structures shows a two-fold increase in the total external quantum efficiency and a four-fold increase in the external quantum efficiency in the forward viewing direction compared to the planar spectrum conversion films without micro-structures.