Intrinsic White-Light Emission from Layered Hybrid Perovskites

We report on the second family of
layered perovskite white-light
emitters with improved photoluminescence quantum efficiencies (PLQEs).
Upon near-ultraviolet excitation, two new Pb–Cl and Pb–Br
perovskites emit broadband “cold” and “warm”
white light, respectively, with high color rendition. Emission from
large, single crystals indicates an origin from the bulk material
and not surface defect sites. The Pb–Br perovskite has a PLQE
of 9%, which is undiminished after 3 months of continuous irradiation.
Our mechanistic studies indicate that the emission has contributions
from strong electron–phonon coupling in a deformable lattice
and from a distribution of intrinsic trap states. These hybrids provide
a tunable platform for combining the facile processability of organic
materials with the structural definition of crystalline, inorganic
solids.