Dynamics of Strong Coupling Between Free Charge Carriers in Organometal Halide Perovskites and Aluminum Plasmonic States.

Yang Luo,Le-Yi Zhao,Yong-Lai Zhang,Hai Wang

doi:10.3389/fchem.2021.818459

Abstract

We have investigated a strong coupled system composed of a MAPbIxCl3-x perovskite film and aluminum conical nanopits array. The hybrid states formed by surface plasmons and free carriers, rather than the traditional excitons, is observed in both steady-state reflection measurements and transient absorption spectra. In particular, under near upper band resonant excitation, the bleaching signal from the band edge of uncoupled perovskite was completely separated into two distinctive bleaching signals of the hybrid system, which is clear evidence for the formation of strong coupling states between the free carrier–plasmon state. Besides this, a Rabi splitting up to 260 meV is achieved. The appearance of the lower bands can compensate for the poor absorption of the perovskite in the NIR region. Finally, we found that the lifetime of the free carrier–SP hybrid states is slightly shorter than that of uncoupled perovskite film, which can be caused by the ultrafast damping of the SPs modes. These peculiar features on the strong coupled hybrid states based on free charge carriers can open new perspectives for novel plasmonic perovskite solar cells.

Highlights

Organometal halide perovskites are emerging as a class of attractive materials for solution-processed optoelectronic devices with outstanding performance.(Jeon et al, 2015; Yang et al, 2015; Long et al, 2020; Chen et al, 2021; Privitera et al, 2021)
We demonstrate that strong SP–free charge carrier coupling can be achieved with CH3NH3PbClxI3–x perovskite film and SPs supported by Al conical nanopits arrays
The band edge transition bleaching is completely separated into two bleaching signals at around 700 and 820 nm, which can be attributed to the upper and lower hybrid SP–free charge carrier states with observation of Rabi splitting energy up to 260 meV

Summary

Introduction

Organometal halide perovskites are emerging as a class of attractive materials for solution-processed optoelectronic devices with outstanding performance.(Jeon et al, 2015; Yang et al, 2015; Long et al, 2020; Chen et al, 2021; Privitera et al, 2021). We demonstrate that strong SP–free charge carrier coupling can be achieved with CH3NH3PbClxI3–x perovskite film and SPs supported by Al conical nanopits arrays. Under upper band resonant excitation, direct evidence of the formation of the hybrid free charge carrier–SP states is clearly shown in the transient absorption (TA) spectra.

Results

Conclusion