Fabrication of Sodium-Doped ZnO Nanorods and Investigation of Their Physical Properties as Electron Transport Layers for Dye-Sensitized Solar Cells W. O. Sukmawati, M. A. Alwasilah, L. Agusu, I. N. Sudiana, S. Teke, I. Usman International Journal of Acta Material Vol. 3 No. 1 2026