VNU Journal of Science Mathematics – Physics, Vol 37, No 2 (2021) 22 30 22 Original Article Energy Level Locations of Lanthanide Ions in Strontium Aluminosilicate Phosphors Ho Van Tuyen*, Nguyen Ha Vi Duy Tan University, 3 Quang Trung, Hai Chau, Da Nang, Vietnam Received 05 August 2020 Revised 29 August 2020; Accepted 15 September 2020 Abstract This paper determines the position of energy levels of lanthanide ions in Sr2Al2SiO7 (SAS) phosphor by a combining analysis of the lowest 4f 5d transit[.]