p-State Luminescence in CdSe Nanoplatelets: The Role of Lateral Confinement and an LO Phonon Bottleneck

Abstract

We report excited state emission from p-states at excitation fluences well below ground state saturation in CdSe nanoplatelets. Size dependent exciton ground state-excited state energies and dynamics are determined by three independent methods, time-resolved photoluminescence (PL), time-integrated PL and Hartree renormalized k$\cdot$p calculations -- all in very good agreement. The ground state-excited state energy spacing strongly increases with the lateral platelet quantization. Our results suggest that the PL decay of CdSe platelets is governed by an LO-phonon bottleneck, related to the reported low exciton phonon coupling in CdSe platelets and only observable due to the very large oscillator strength and energy spacing of both states.

References in corpus (3)

• Low-threshold stimulated emission using colloidal quantum wells
• Evidence of giant oscillator strength in the exciton dephasing of CdSe nanoplatelets measured by resonant four-wave mixing
• Tight-binding calculations of image charge effects in colloidal nanoscale platelets of CdSe

Cited by in corpus (7)

• Addressing the exciton fine structure in colloidal nanocrystals: the case of CdSe nanoplatelets
• Excitons in core-only, core-shell and core-crown CdSe nanoplatelets: interplay between in-plane electron-hole correlation, spatial and dielectric confinement
• Strong exciton-photon coupling with colloidal nanoplatelets in an open microcavity
• Nanoplatelets as material system between strong confinement and weak confinement
• Observation of the quantized motion of excitons in CdSe nanoplatelets
• Dielectric Confinement Enables Molecular Coupling in Stacked Colloidal Nanoplatelets
• Fourier-imaging of single self-assembled CdSe nanoplatelet chains and clusters reveals out-of-plane dipole contribution