Semiconductor nanomaterial-based polarized light emission: From materials to light emitting diodes

The overall optical efficiency of backlight-based liquid crystal displays (LCDs) is less than 5% due to the loss of backlight source by polarizers, color filter, liquid crystal layer and so on. Self-emissive light emitting diodes (LEDs) have been undergoing huge development due to their substantial market potentials to meet the demand of future display. More importantly, the polarized LEDs could enhance the energy utilization efficiency by avoiding light loss caused by polarizers. Therefore, it is desirable to look for effective methods to assemble high-quality anisotropic nanomaterial films so as to fabricate polarized LEDs with high degree of polarization and external quantum efficiency. Here, the photoelectrical properties of some semiconductor nanomaterials and their potential applications for polarized LEDs are introduced. The research progress in the field of polarized light emission from materials to films and then to LEDs is reviewed. Mechanisms of polarized emission, and different assembly strategies for polarized light emitting films and LEDs are also summarized and compared. Finally, several current challenges are discussed, and perspectives on future potential commercial application of polarized LEDs are offered. We hope this review will provide a valuable summary on current status and stimulate some new insightful ideas for future development of polarized LEDs.