Exciton-to-Dopant Energy Transfer in Mn-Doped Cesium Lead Halide Perovskite Nanocrystals

Abstract

We report the one-pot synthesis of colloidal Mn-doped cesium lead halide (CsPbX 3 ) perovskite nanocrystals and efficient intraparticle energy transfer between the exciton and dopant ions resulting in intense sensitized Mn luminescence. Mn-doped CsPbCl 3 and CsPb(Cl/Br) 3 nanocrystals maintained the same lattice structure and crystallinity as their undoped counterparts with nearly identical lattice parameters at ∼0.2% doping concentrations and no signature of phase separation. The strong sensitized luminescence from d−d transition of Mn 2+ ions upon band-edge excitation of the CsPbX 3 host is indicative of sufficiently strong exchange coupling between the charge carriers of the host and dopant d electrons mediating the energy transfer, essential for obtaining unique properties of magnetically doped quantum dots. Highly homogeneous spectral characteristics of Mn luminescence from an ensemble of Mn-doped CsPbX 3 nanocrystals and well-defined electron paramagnetic resonance spectra of Mn 2+ in host CsPbX 3 nanocrystal lattices suggest relatively uniform doping sites, likely from substitutional doping at Pb 2+ . These observations indicate that CsPbX 3 nanocrystals, possessing many superior optical and electronic characteristics, can be utilized as a new platform for magnetically doped quantum dots expanding the range of optical, electronic, and magnetic functionality.

Probing molecule-like isolated octahedra via phase stabilization of zero-dimensional cesium lead halide nanocrystals

“…It is interesting to note the increase in Cs 4 PbX 6 host emission after Mn doping (Fig. 2a–c) in both mixed halide and chloride analog, similar to the perovskite nanocrystals 38 . The host emission increment is more prominent in the mixed halide (Br/Cl) analog than pure chloride, which is presumed to the passivation effect of chloride ion, on the pre-existing defects of the host 38 .…”

“…2a–c) in both mixed halide and chloride analog, similar to the perovskite nanocrystals 38 . The host emission increment is more prominent in the mixed halide (Br/Cl) analog than pure chloride, which is presumed to the passivation effect of chloride ion, on the pre-existing defects of the host 38 . Therefore, Mn 2+ doping significantly alters the competitive kinetics between the radiative and non-radiative relaxation process of the Cs 4 PbX 6 host.…”

Organic–inorganic metal halide hybrids beyond perovskites

“…Electronic and optical properties of semiconductors can be efficiently manipulated by doping different metal ions, such as Mn 2+ [15,16], Sn 2+ , Cd 2+ , Zn 2+ [146], Bi 3+ [147], Au 3+ [148], and various lanthanide ions (Ce 3+ , Sm 3+ , Eu 3+ , Tb 3+ , Dy 3+ , Er 3+ , and Yb 3+ ) [149]. Among all these doped metal ions, Mn 2+ has attracted the most research attention, owing to the intriguing properties of Mn-doped metal halide hybrids, e.g.…”

“…facile control of the doping concentration, highly luminescent red emission, efficient energy transfer. Since 2016, doping Mn 2+ ions into all inorganic perovskite CsPbX 3 NCs has been extensively explored [15,16,61,[150][151][152]. In these CsPbCl 3 and CsPb(Cl/Br) 3 nanocrystals, strong sensitized luminescence from d-d transition of Mn 2+ was observed due to the strong exchange coupling between the charge carriers of the host and dopant d electrons mediating the energy transfer ( Figure 9(a,b)).…”

“…In an extreme case, when the metal halides are completely isolated by the organic moieties, 0D structure at the molecular level can be obtained to display the intrinsic properties of individual metal halide species [14]. In addition to structure control, doping Mn ions to this class of materials to achieve efficient red emission has been realized in different hybrids [15][16][17][18]. Replacing Pb 2+ by nontoxic trivalent and monovalent metals can yield double perovskites (A 2 B I B III X 6 ), which provides a new route to fabricate lead-free PVs and other optoelectronic devices [19].…”