Syntheses, Structures, and Photoluminescence of Copper-Based Halides

Copper-based halides have been found to be a new family of lead-free materials with high stability and superior optoelectrical properties. In this work, we report the photoluminescence of the known (C 8 H 14 N 2 )CuBr 3 and the discovery of three new compounds, (C 8 H 14 N 2 )CuCl 3, (C 8 H 14 N 2 )CuCl 3 ·H 2 O, and (C 8 H 14 N 2 )CuI 3, which all exhibit efficient light emissions. All these compounds have monoclinic structures with the same space group ( P 2 1 / c ) and zero-dimensional (0D) structures, which can be viewed as the assembly of promising aromatic molecules and different copper halide tetrahedrons. Upon the irradiation of deep ultraviolet light, (C 8 H 14 N 2 )CuCl 3, (C 8 H 14 N 2 )CuBr 3,, and (C 8 H 14 N 2 )CuI 3 show green emission peaking at ∼520 nm with a photoluminescent quantum yield (PLQY) of 3.38, 35.19, and 17.81%, while (C 8 H 14 N 2 )CuCl 3 ·H 2 O displays yellow emission centered at ∼532 nm with a PLQY of 2.88%. A white light-emitting diode (WLED) was successfully fabricated by employing (C 8 H 14 N 2 )CuBr 3 as a green emitter, demonstrating the potential of copper halides for applications in the green lighting field.