An orange‐emitting phosphor BaSrGa 4 O 8 :Bi 3+ ,K + with unique one‐dimensional chain structure for high index color WLEDs

It has been an urgent need for developing a new bright long‐wave emitting phosphor to improve the color rendering index (CRI) of white light‐emitting diodes (WLEDs). Here, based on the concept of oxygen vacancy‐induced long‐wave emission by Bi 3+ doping, we selected BaSrGa 4 O 8 as the matrix, which has a low‐dimensional chain structure that can produce enough oxygen vacancies. After the introduction of Bi 3+ , orange emission was successfully achieved. To further improve the luminescence efficiency, the system of BaSrGa 4 O 8 :Bi 3+ ,K + was designed. Interestingly, although significant emission enhancement was obtained, the material showed reduced absorption with increased oxygen vacancies. More detailed experimental evidences confirm that oxygen vacancies can activate Bi 3+ to achieve long‐wave emission. Our results provide a new way to design Bi 3+ ‐based long‐wave emitting phosphors with low‐dimensional crystal structure. Finally, a WLED device containing BaSrGa 4 O 8 :Bi 3+ ,K + was fabricated and exhibited an enhanced CRI, which shows a promising application in WLEDs.