Colloidal Nanocrystals Regrowth-Assisted Synthesis of Perovskite Microwire Lasers For Integrated Optoelectronics

Abstract

Colloidal perovskite nanocrystals (NCs) are a well-proven platform for growing anisotropic structures. Nanowires (NWs) exhibiting a quantum confinement phenomenon and microwires (MWs), which enable lasing, are of particular interest for optoelectronic devices. Synthesis of the latter is challenging. Herein, we report a straightforward access to high-quality ${\mathrm{CsPbBr}}_3$ MW lasers. We utilize a diphenyl ether (DPE) solvent for the hot-injection synthesis. DPE coordinates strongly to ${\mathrm{Pb}}^{2+}$ and allows to reduce an excess of oleic acid/oleylamine ligand pair, well-established for ${\mathrm{PbBr}}_2$ dissolution and inhibition of as-formed NCs regrowth. Therefore, a rapid injection of Cs-oleate into the ${\mathrm{PbBr}}_2$-containing solution yields lead-depleted ${\mathrm{Cs}}_4{\mathrm{PbBr}}_6$ NCs, which gradually convert into ${\mathrm{CsPbBr}}_3$ counterparts. The latter transform into NWs through an oriented-attachment mechanism, which in turn evolve into laser MWs. To demonstrate spectrally tunable lasing in MWs we employ ${\mathrm{YCl}}_3$ for ion exchange in the perovskite lattice. Resultant CsPb(Cl,Br)${}_3$ MWs show high-Q coherent emission in the 485–540 nm range. To highlight the potential of synthesized MWs for integrated optoelectronics, we assemble a device comprising a CsPb(Cl,Br)${}_3$ MW laser coupled to ${\mathrm{MoO}}_3$ lossless nanowaveguide, which delivers coherent light to a ${\mathrm{CsPbBr}}_3$ MW photodetector. The device exhibits a nonlinear optoelectronic response applicable for on-chip neuromorphic computing.