Organic-Inorganic perovskites CsPbX3(X = Cl, Br, I) are investigated for their potential ability and use as solar cells and energy storage materials, using density function theory, generalized gradient approximation and modified Becke-Johnson (TB-mBJ) exchange potential. Structural analysis shows that the lattice constant and unit cell volume varies when CsPbX3(X = Cl, Br, I) change from cubic phase to tetragonal and orthorhombic structures. The electronic properties show that CsPbCl3, CsPbBr3and CsPbI3all are semiconductor in with bandgap between 0.79 eV and 2.54 eV. It is also observed that the bandgap changes when the structure changes. Optical properties show that these materials have a good absorption ability of photons due to their narrow bandgaps. The real ε1(ω) and imaginary ε2(ω) parts of their dielectric functions show that CsPbCl3, CsPbBr3and CsPbI3also possess a great ability of retaining the energy it absorbs. These properties make them very suitable for solar cells and energy storage applications. These materials also behave as superluminescent material at high photon energy.