Citation: Denis, Paul-Henry; Mertens, Martijn; Van Gompel, Wouter T. M.; Van Hecke, Kristof; Ruttens, Bart; D’ Haen, Jan; Lutsen, Laurence; Vanderzande, Dirk (2021). Directing the Self-Assembly of Conjugated Organic Ammonium Cations in Low-Dimensional Perovskites by Halide Substitution. Chemistry of Materials, , pp. -.