Design of a superb Eu <sup>2+</sup> –Mn <sup>2+</sup> co‐doped narrow‐band green phosphor via nearly 100% energy transfer efficiency
Guang‐Tao Lu, Yichao Wang, Siqi Piao, Jinsu Zhang, Xizhen Zhang, Xufeng Zhou, Yongze Cao, Xiangping Li, Baojiu Chen
Abstract
Abstract The excellent narrow‐band emitters, especially the green ones, are regarded as a pivotal research direction for light‐emitting diodes (LED) backlights in liquid‐crystal displays (LCDs). A nearly single‐peak green emission centered at 513 nm with a full width at half maximum of 28 nm is reached in KAl 11 O 17 :0.1Eu 2+ , 0.15Mn 2+ phosphor via nearly 100% energy transfer (ET) efficiency, and the extended X‐ray absorption fine structure analysis elucidates its mechanism, which is that Eu 2+ and Mn 2+ are constrained to form Eu 2+ –Mn 2+ pairs with a small distance 3.7 Å caused by the local environment relaxation inducement. Meanwhile, by creating an unhindered energy flow between Eu 2+ , Mn 2+ and K + /O 2− defect levels through ET and multilevel electron trapped and recombination process, the KAO:Eu 2+ , Mn 2+ phosphors perform superb photoluminescence property with a high color purity of 83%, an excellent thermal stability (94%@200°C), and unexceptionable internal and external quantum efficiencies of 91.7% and 66.4%, which all are superior to characteristics of commercial β‐SiAlON:Eu 2+ phosphor. Moreover, the white LED fabricated using KAO:Eu 2+ , Mn 2+ to provide green component shows a wide color gamut of 105% National Television System Committee. These results indicate a potential for an application of our material in LCD–LED backlights, and the design of such local relaxation‐induced structure provides a significative reference to develop the new narrow‐band emitters.