Evidence and implications for exciton dissociation in lead halide perovskites Vandana Tiwari, Hong-Guang Duan, Ajay Jha, Pabitra K. Nayak, Michael Thorwart, Henry J. Snaith and R. J. Dwayne Miller EPJ Web Conf., 205 (2019) 06018 Published online: 16 April 2019 DOI: 10.1051/epjconf/201920506018