Abstract: A perovskite material that has a perovskite crystal lattice having a formula of CxMyXz, and alkyl polyammonium cations disposed within or at a surface of the perovskite crystal lattice; wherein x, y, and z, are real numbers; C comprises one or more cations selected from the group consisting of Group 1 metals, Group 2 metals, ammonium, formamidinium, guanidinium, and ethene tetramine; M comprises one or more metals each selected from the group consisting of Be, Mg, Ca, Sr, Ba, Fe, Cd, Co, Ni, Cu, Ag, Au, Hg, Sn, Ge, Ga, Pb, In, Tl, Sb, Bi, Ti, Zn, Cd, Hg, and Zr, and combinations thereof; and X comprises one or more anions each selected from the group consisting of halides, pseudohalides, chalcogenides, and combinations thereof.