Methylammonium lead bromide (MAPbBr<sub>3</sub>) perovskite nanoparticles
(NPs) have been recently proposed as a new material for light-emitting
diodes, as well as a new paradigm to elucidate the operational mechanism
in perovskite solar cells. Here, we have expanded the synthesis concept
to fabricate NPs based on formamidinium lead bromide (FAPbBr<sub>3</sub>). Importantly, we have demonstrated that the photophysical features
of this novel material can be easily tuned by exchanging the organic
cation, achieving lower radiative bimolecular recombination rate for
FAPbBr<sub>3</sub> NPs. Additionally, we report for the first time
light-emitting electrochemical cells (LECs) based on perovskite NPs
by an easily up-scalable spray-coating technique. Stable luminance
of 1–2 cd/m<sup>2</sup> at low driving currents was achieved
for both types of materials. Overall, this work opens a new avenue
of research into the field of organic–inorganic metal halide
nanoparticles bearing different alkyl ammonium groups and their application
in the developing field of thin-film lighting devices
