Interplay between Perovskite Magic-Sized Clusters and Amino Lead Halide Molecular Clusters.

Evan T Vickers,Tyler Smart,Ziyi Chen,Yuan Ping,Peng Zhang,Vivien Cherrette,Jin Z Zhang

doi:10.34133/2021/6047971

Abstract

Recent progress has been made on the synthesis and characterization of metal halide perovskite magic-sized clusters (PMSCs) with ABX3 composition (A = CH3NH3+ or Cs+, B = Pb2+, and X = Cl−, Br−, or I−). However, their mechanism of growth and structure is still not well understood. In our effort to understand their structure and growth, we discovered that a new species can be formed without the CH3NH3+ component, which we name as molecular clusters (MCs). Specifically, CH3NH3PbBr3 PMSCs, with a characteristic absorption peak at 424 nm, are synthesized using PbBr2 and CH3NH3Br as precursors and butylamine (BTYA) and valeric acid (VA) as ligands, while MCs, with an absorption peak at 402 nm, are synthesized using solely PbBr2 and BTYA, without CH3NH3Br. Interestingly, PMSCs are converted spontaneously overtime into MCs. An isosbestic point in their electronic absorption spectra indicates a direct interplay between the PMSCs and MCs. Therefore, we suggest that the MCs are precursors to the PMSCs. From spectroscopic and extended X-ray absorption fine structure (EXAFS) results, we propose some tentative structural models for the MCs. The discovery of the MCs is critical to understanding the growth of PMSCs as well as larger perovskite quantum dots (PQDs) or nanocrystals (PNCs).

Highlights

Semiconductor perovskite nanocrystals (PNCs) or quantum Bd(Mor-t,As o+(r)P, QIC-)DHhs()aNvbeHa2ds)er2da+wo(nFnAsit)ghneoirfifocCarmns+tu; rlBaes=eAaPBrcbXh23+,i(nASten=r2e+Cs;tHsX3d=NuHeCl3t−o+, their bandgap tunability, high photoluminescence quantum yield (PLQY), and sharp emission peaks that are attractive for LEDs and other optoelectronic applications [1–12]
Detail of the MAPbBr3-valeric acid (VA)-BTYA Perovskite magic-sized clusters (PMSCs) synthesis is described in the supporting information (SI)
The UV-vis absorption and PL spectra of MAPbBr3-VA-BTYA PMSC solution are shown in Figure 1(a), with the major absorption peak at 424 nm and PL peak at 434 nm, as we reported previously [20]

Summary

Introduction

Semiconductor perovskite nanocrystals (PNCs) or quantum Bd(Mor-t,As o+(r)P, QIC-)DHhs()aNvbeHa2ds)er2da+wo(nFnAsit)ghneoirfifocCarmns+tu; rlBaes=eAaPBrcbXh23+,i(nASten=r2e+Cs;tHsX3d=NuHeCl3t−o+, their bandgap tunability, high photoluminescence quantum yield (PLQY), and sharp emission peaks that are attractive for LEDs and other optoelectronic applications [1–12]. We carried out a more detailed study to help shed light on these MCs and their relation to PMSCs. In addition, the MC synthesis was demonstrated using PbBr2 and was successful with PbCl2 and PbI2 precursors. The UV-vis absorption and PL spectra of MAPbBr3-VA-BTYA PMSC solution are shown, with the major absorption peak at 424 nm and PL peak at 434 nm, as we reported previously [20].

Results

Conclusion