Uncovering temperature-dependent exciton-polariton relaxation mechanisms in hybrid organic-inorganic perovskites

Abstract

Hybrid perovskites have emerged as a promising material candidate for exciton-polariton (polariton) optoelectronics. Thermodynamically, low-threshold Bose-Einstein condensation requires efficient scattering to the polariton energy dispersion minimum, and many applications demand precise control of polariton interactions. Thus far, the primary mechanisms by which polaritons relax in perovskites remains unclear. In this work, we perform temperature-dependent measurements of polaritons in low-dimensional perovskite wedged microcavities achieving a Rabi splitting of $${{{\hslash }}\Omega }_{{Rabi}}$$ ℏ Ω R a b i = 260 ± 5 meV. We change the Hopfield coefficients by moving the optical excitation along the cavity wedge and thus tune the strength of the primary polariton relaxation mechanisms in this material. We observe the polariton bottleneck regime and show that it can be overcome by harnessing the interplay between the different excitonic species whose corresponding dynamics are modified by strong coupling. This work provides an understanding of polariton relaxation in perovskites benefiting from efficient, material-specific relaxation pathways and intracavity pumping schemes from thermally brightened excitonic species.

Polaritonic Bottleneck in Colloidal Quantum Dots

“…A similar behavior was observed when either the photon energy is significantly below the onset of the NC absorption (panel (b)) or at lower temperatures (panel (c)). We note in passing that an analogous behavior was recently reported for a 2D quantum well system, where a significant slowing down of the relaxation dynamics was observed by manipulating the energy of the photon mode …”

“…We note in passing that an analogous behavior was recently reported for a 2D quantum well system, where a significant slowing down of the relaxation dynamics was observed by manipulating the energy of the photon mode. 20 To understand the emergence of this polaritonic-induced phonon bottleneck, we plot in Figure 4a the polaritonic energies E ( ) n in the absence of a cavity (excitonic energies, E n ) and for 4 different photon energies. The cavity coupling is set to ℏg Xd 1 = 50 meV.…”

“…This approach has been applied for J-aggregates, two-dimensional quantum wells, and bulk materials ,− and is also popular for controlling the electronic properties of molecular systems, and in particular how the products in chemical reactions can be tuned by coupling with light, with reported reactions being selective, slower or faster in optical cavities. , In addition, such hybrid states exhibit unique properties that make them relevant for a wide range of applications, including lasers, − Bose–Einstein condensates, − and quantum bits. − A deep understanding along with a theoretical description of the polaritonic dynamics is available for molecules and relatively small system sizes, while the description of realistic materials is still lacking.…”

Controlling Exciton/Exciton Recombination in 2-D Perovskite Using Exciton–Polariton Coupling

“…A Fabry–Pérot microcavity consists of two partially reflective mirrors and has been demonstrated for room-temperature polariton formation, manipulation, lasing, and condensation . The strength of the exciton/polariton coupling in such cavities can be controlled by controlling the quality factor, the relative layer thicknesses inside the cavity, and other aspects such as temperature and polarization. , …”

“…7 The strength of the exciton/polariton coupling in such cavities can be controlled by controlling the quality factor, the relative layer thicknesses inside the cavity, and other aspects such as temperature and polarization. 8,9 2D transition metal dichalcogenides (2D-TMDCs) with strong light absorption and large exciton binding energies have been proposed and some have been demonstrated to offer a distinctive platform to achieve room temperature strong coupling. 10 Similarly, 2D metal-halide perovskites as another class of 2D semiconductors exhibit intriguing optoelectronic properties, including high optical absorption, large and tunable exciton binding energies, 11 and high carrier mobilities, while showcasing a unique set of excitonic effects that becomes more pronounced as they transition from the bulk to the confined multiple quantum wells structure of the 2D configuration (e.g., metal-halide layer thickness).…”