Cirtopic white LED with a 490 nm emission peak based on He-Zn annealed ZnO nanorods/polymer blend p-n heterojunction

A white light emitting diode (WLED) based on ZnO nanorods (ZNRs)/polymer blend p-n heterojunction has been fabricated. Different from the common commercial GaN WLEDs with a blue emission, the ZNRs/polymer blend WLED exhibits a blue-green emission peaked at 490 nm. Thus, the ZNRs/polymer blend WLED has a better cirtopic effect and smaller blue-light hazard. To get the 490 nm emission, intrinsic n-type ZNRs were annealed in a mixed gas of He and Zn vapor, and poly (9, 9-dioctylfluorene) (PFO) was mixed into the p-type polymer blend. Poly (3-hexylthiophene) (P3HT) was also mixed into the blends to get red emission. Results show the ZNRs/polymer blend heterojunction exhibits high-quality white-light emission with superior chromaticity coordinate (0.30, 0.33) as well as good cirtopic-effect spectrum. In comparison with the commercial GaN WLED, the ZNRs/polymer blend WLED is significantly potential for human health and work efficiency.