Here, we have synthesised a range of samples, with the formula (CH3NH3)1−2x(H3NC2H4NH3)xPbI3, with different levels of ethylenediammonium substitution to probe non-stoichiometry at the A-site of the perovskite. A single phase region was identified and is accompanied by a change in photophysical properties. The influence of aliovalent substitution with ethylenediammonium results in a decrease in HOMO level from −5.31 eV for x = 0 to −5.88 eV for x = 0.15.
Payne, J. L., Ni, C., Harwell, J. R., Jagadamma, L. K., McDonald, C., Mariotti, D., Samuel, I. D. W., & Irvine, J. T. S. (2018). Probing the structure–property–composition relationship in organic–inorganic tri-halide perovskites. Physical Chemistry Chemical Physics, 20(31), 20489-20496. https://doi.org/10.1039/C8CP01871E