“Beating the thermodynamic limit with photo-activation of n-doping in organic semiconductors,” X. Lin, B. Wegner, K.M. Lee, M.A. Fusella, F. Zhang, K. Moudgil, B.P. Rand, S. Barlow, S.R. Marder, N. Koch, A. Kahn, Nat. Mater. 16, 1209 (2017).