Abstarct: Abstract In this thesis, the mechanical, electronic and optical properties of perovskite structures for the design of optimized solar cells are investigated. For this purpose, computer simulations baxsed on molecular dynamics and density functional theory methods have been used. The results of molecular dynamics simulations estimated the 46.75 GPa for Young's modulus and 4.76 GPa for final strength of CH3NH3SnI3 perovskite structure. This mechanical behavior indicated the possibility of using this perovskite structure in different temperature conditions as an active laxyer in perovskite solar cells. On the other hand, the results of the simulations baxsed on the density functional theory predicted a direct energy gap of 1.38 eV by using the GW approximation for this peroveskite. On the other hand, calculations related to optical properties showed the minimum value of reflection coefficient and the maximum value of absorption and dissipation coefficient for this structure in the energy interval of 1.5 eV to 3 eV, which these rates indicates the appropriate optical behavior of CH3NH3SnI3 structure as the active laxyer in the peroveskite baxsed solar cells. Further, other physical properties such as temperature change of the simulated structure, inserting atomic defects in the simulated structure, and limiting perovskite structures to 2-dimension implemented to CH3NH3SnI3, in order to study the real behavior of this atomic structure in more detail. Numercially, by applying these cases effects, the band gap value of the structures, which expresses their electronic and optical behavior, was changed to 1.25 eV, 1.22 eV and 1.34 eV, respectively.