Xiao, Z.G. Bi, C., Shao, Y.C., Dong, Q.F., Wang, Q., Yuan, Y.B., Wang, C.G., Gao, Y.L. and Huang, J.S. (2014) Efficient, high yield perovskite photovoltaic devices grown by interdiffusion of solution-processed precursor stacking layers. Energy & En-vironmental Science, 7, 2619-2623.