White organic light-emitting diodes (OLEDs) hold great promise for applications in displays and lighting due to high efficiency and superior white color balance. However, further improvement in efficiency remains a continuous and urgent demand due to limited energy flow extraction. A powerful method for drastically releasing the trapped energy flow in conventional white OLEDs is demonstrated by implementing unique quasi-periodic subwavelength nanofunnel arrays (NFAs) via soft nanoimprinting lithography, which is ideal for enhancing light extraction without any spectral distortion or angular dependence. The resulting efficiency is over 2 times that of a conventional OLED used as a comparison. The external quantum efficiency and power efficiency are raised to 32.4% and 56.9 lm W-1, respectively. Besides, the substantial increase in efficiency over a broad bandwidth with angular color stability, the experimental proofs show that the NFA-based extraction structure affords the enticing capacity against scrubbing and the self-cleaning feature, which are critical to the commercial viability in practical applications.
|Number of pages||9|
|Journal||Advanced Functional Materials|
|Publication status||Published - 13 May 2015|
- light extraction
- nanofunnel arrays
- soft nanoimprinting lithography
- white organic light-emitting diodes