“Study of Structural Properties of Solar Energy Material CH3 NH3 PbX3 (X= I, Br and Cl) Perovskites and its Mixed Halides Using Density Functional Theory”, Nepal Journal of Science and Technology, vol. 21, no. 2, pp. 105–114, Dec. 2022, doi: 10.3126/njst.v21i2.62360.