A generic interface to reduce the efficiency-stability-cost gap of perovskite solar cells por Hou, Y, Du, X, Scheiner, S, McMeekin, DP, Wang, Z, Li, N, Killian, MS, Chen, H, Richter, M, Levchuk, I, Schrenker, N, Spiecker, E, Stubhan, T, Luechinger, NA, Hirsch, A, Schmuki, P, Steinrück, H-P, Fink, RH, Halik, M, Snaith, HJ, Brabec, CJ