Direct linearly polarized electroluminescence from perovskite nanoplatelet superlattices by Ye, J, Ren, A, Dai, L, Baikie, TK, Guo, R, Pal, D, Gorgon, S, Heger, JE, Huang, J, Sun, Y, Arul, R, Grimaldi, G, Zhang, K, Shamsi, J, Huang, Y-T, Wang, H, Wu, J, Femius Koenderink, A, Torrente Murciano, L, Schwartzkopf, M, Roth, SV, Müller-Buschbaum, P, Baumberg, JJ, Stranks, SD, Greenham, NC, Polavarapu, L, Zhang, W, Rao, A, Hoye, RLZ