Room-Temperature Cavity Polaritons with 3D Hybrid Perovskite: Toward Large-Surface Polaritonic Devices

Abstract

Hybrid halide perovskites are now considered as key materials for contemporary research in photovoltaics and nanophotonics. In particular, because these materials can be solution processed, they represent a great hope for obtaining low cost devices. While the potential of 2D layered hybrid perovskites for polaritonic devices operating at room temperature has been demonstrated in the past, the potential of the 3D perovskites has been much less explored for this particular application. Here, we report the strong exciton-photon coupling with 3D bromide hybrid perovskite. Cavity polaritons are experimentallly demonstrated from both reflectivity and photoluminescence experiments, at room temperature, in a 3λ/2 planar microcavity containing a large surface spin-coated CH 3 NH 3 PbBr 3 thin film. A microcavity quality factor of 92 was found and a large Rabi splitting of 70 meV was measured. This result paves the way to low-cost polaritonic devices operating at room temperature, potentially electrically injectable as 3D hybrid perovskites present good transport properties.Cavity polaritons are half-light half-matter quasiparticles arising from the strong coupling regime between excitonic and photonic modes [1]. Such regime is achieved when the coupling strength, related to the oscillator strength quantifying the light-matter interaction in a material, is larger than the dissipation rates of uncoupled excitons and cavity photons. Thanks to its hybrid nature, cavity polaritons inherit the best features of both the excitonic and photonic component: strongly nonlinear bosonic particles which can propagate balistically over macroscopic distance, and can be injected/probed via optical means. These fascinating properties suggest not only a playground for studying physics of out of equilibrium Bose Einstein condensation, but also a potential platform for all-optical devices. In the later direction, many proof-of-concepts of polaritonic devices have been reported: polaritonic lasers [2], polariton transistors [3], resonant tunnelling diodes [4], interferometer [5], optical gates [3], and optical router [6]. Most of these demonstrations are in GaAs-based system the most accomplished technologies to engineer cavity polaritons. However, due to the small excitonic effects and oscillator strength in GaAs, their operating regime is limited to cryogenic temperature. For this reason, materials presenting strong excitonic effects at room temperature, such as the high band gap materials GaN [7,8] or ZnO [9, 10] are actively studied. However, the achievement of inorganic semiconductor engineered confined microstructures need sophisticated and high * emmanuelle.deleporte@ens-cachan.fr temperature epitaxial techniques. Looking for low-cost solutions, soft chemistry and low temperature processed materials presenting strong excitonic effects were also considered. The strong coupling regime at room temperature has been demonstrated in planar microcavities containing organic materials [11][12][13][14] or organic-inorganic halide perovskites such ...

Directing Random Lasing Emission Using Cavity Exciton-Polaritons

“…Let us now focus on the 3λ/2 MAPB-based microcavity. In our previous study [50], the strong coupling between the perovskite's exciton and the microcavity photonic mode has been demonstrated on a similar microcavity and cavity polaritons have been observed experimentally (more details on the theory of the cavity polaritons are given in the methods section). In particular, we have shown that, due to the overall lateral roughness of the MAPB and PMMA layers, the cavity detuning, δ = E 0 − E X , with E 0 the cavity mode energy at normal incidence and E X the exciton energy, can be tuned by probing different lateral positions.…”

“…Besides, strong coupling between a microcavity mode and an exciton has been observed both in 2D and 3D hybrid perovskites [46][47][48][49][50].…”

“…Indeed, the gain occurs within the plane of the MAPB film and the lasing emission is scattered out of the plane, resulting in an angle-independent emission from the surface of the MAPB/PMMA sample. Considering the ease with which the strong coupling regime is observed in MAPB [50][51][52], the question of the photonic or polaritonic nature of the lasing can be reasonably raised here as it was raised by Niyuki et al from a resonance-controlled ZnO random laser [53]. Especially, the blueshift of the MAPB/PMMA lasing peaks (of around 1-2 meV between 1.1 and 1.8 P th , see section 2 of the Supplementary) could be in favour of a polaritonic lasing.…”

“…This was due to the overall lateral roughness of the MAPB and PMMA layers. Only the lower cavity polariton dispersion can be observed in the ARPL maps of our previous study [50]. We will then only consider the lower cavity polariton whose eingenvalue µ LP (θ) is given by equation 1 :…”

“…Additional data are shown in the section 3 of the supplementary for each of these positions, including the map-integrated PL intensity as a function of the pump power demonstrating the lasing action of these positions. The dispersions corresponding to the three positions below the threshold (at 0.1, 0.1 and 0.2 P th ) are fitted with the lower cavity polariton dispersion, with the detuning, δ, as the only free parameter and the other parameters fixed at the values found in our previous study [50]. More details on the fitting method is presented in the section 4 of the supplementary.…”