Retraction notice to “Photocurrent enhancement by Ni2+ and Zn2+ ion doped in SnO2 nanoparticles in highly porous dye-sensitized solar cells” [Ceram. Int. 40 (2014)11619–11626, (S0272884214004933), (10.1016/j.ceramint.2014.03.152)]

1. Shalan, A.E.
2. Rasly, M.
3. Osama, I.
4. Rashad, M.M.
5. Ibrahim, I.A.