Highly Luminescent and Stable 2D/3D Octadecylammonium/Formamidinium Lead Bromide Perovskite Films

We developed a facile approach to fabricate highly luminescent and stable quasi-2D/3D (ODA)(2)FA(n-1)Pb(n)Br(3n+1)/FAPbBr(3) (ODA: octadecylammonium; FA: formamidinium) perovskite films. Trace amounts of octadecylamine dissolved in toluene used as an antisolvent were partially protonated by FAPbBr(3) and interacted with [PbBr6](4-) octahedral layers, forming quasi-2D perovskites. Moreover, octadecylamine uniformly and densely covered the perovskite surface rendering it hydrophobic and prevented penetration of water, making these perovskite films stable and strongly luminescent in water for several tens of minutes without any encapsulation. Adjusting the concentration of octadecylamine, we were able to produce perovskite films with an exceptionally high photoluminescence quantum yield (PL QY) of 91%, which was ascribed to the efficient energy funneling from the 2D to the 3D perovskite phase and the passivation action of the organic additive.

Automated summary

A facile approach was developed to fabricate highly luminescent and stable quasi-two-dimensional/three-dimensional perovskite films, which exhibited strong luminescence and stability in water for several tens of minutes without encapsulation. The high photoluminescence quantum yield of 91% was attributed to the efficient energy funneling between two-dimensional and three-dimensional perovskite phases and the passivation effect of the organic additive.