Strong Exciton–Photon Coupling in Hybrid Inorganic–Organic Perovskite Micro/Nanowires

Abstract

breakthrough in power conversion efficiency of 22.1%, [19] comparable to conventional silicon based solar cell. Wavelength tunable LEDs and optically pumped lasers have been achieved by simply changing the ration of halide anions. However, there are still challenges in electroluminescence with high efficiency and electrically pumped lasers. [20] One intrinsic limitation in perovskite is relatively low exciton binding energy that cannot suppress the exciton ionization in the working condition devices. [21] For example, microwave photoconductance and photoluminescence (PL) study revealed exciton binding energy of 18-32 meV [22,23] in MAPbI 3 , comparable to room temperature thermal energies of K B T ≈ 25 meV. By substitution doping of Cl, larger exciton binding energy of 62.3 ± 8.9 meV can be obtained in perovskite thin film. [24] In MAPbBr 3 quantum dots, exciton binding energy can be as large as 375 meV in comparison to their bulk counterpart of 65 meV. [25] In this regard, low dimensional perovskite single crystals with optical or size confinement are becoming promising in complementing their bulk counterparts. With reduced dimensionality, lead halide perovskite provides a platform where exciton behavior, such as exciton-photon interaction [26,27] and exciton binding energy, [28] can be well modulated, giving the pathway to obtain highly efficient optoelectronic devices.

Metal halide perovskite nanocrystals and their applications in optoelectronic devices

“…It can be seen that the theoretically calculated E b values of CsPbCl 3 and CsPbBr 3 are greater than the thermal energy value at RT, which indicates that CsPbCl 3 and CsPbBr 3 are optically more favorable. In fact, the relative accuracy of theoretical calculations was confirmed by experimental temperature‐dependent absorption, optical absorption, and magnetoabsorption …”

Advances in inorganic and hybrid perovskites for miniaturized lasers

“…This can be attributed to the strong light − matter interactions in the NWs using the exciton-polariton model. Zhang et al also comprehensively investigated strong exciton-photon coupling in micro/nanowires system with low-threshold polariton lasing at room temperature [62]. As shown in Figure 3E, large-area CsPbX 3 NW laser arrays (length: ~10-20 μm) were achieved by vapor growth method with low threshold (~4 μJ/cm 2 ) and high quality factor (~2256) under excitation by 400 nm, 100 fs and 1 kHz laser [56].…”

Active meta-optics and nanophotonics with halide perovskites

“…close to the thresholds of amplified spontaneous emission (≈10 17 ÷10 18 cm −3 ). The coexistence of excitons and free-carriers in this regions raises debates on lasing mechanism in 3D halide perovskites [79][80][81][82] .…”