Four-wave mixing in perovskite photovoltaic materials reveals long dephasing times and weaker many-body interactions than GaAs

Abstract

Perovksite semiconductors have shown promise for low-cost solar cells, lasers and photodetectors, yet their fundamental photophysical properties are not well understood. Recent observations of a low ($\sim$few meV) exciton binding energy and evidence of hot phonon effects in the room temperature phase suggest that perovskites are much closer to inorganic semiconductors than the absorber layers in traditional organic photovoltaics, signaling the need for experiments that shed light on the placement of perovskite materials within the spectrum of semiconductors used in optoelectronics and photovoltaics. Here we use four-wave mixing (FWM) to contrast the coherent optical response of CH${}_3$NH${}_3$PbI${}_3$ thin films and crystalline GaAs. At carrier densities relevant for solar cell operation, our results show that carriers interact surprisingly weakly via the Coulomb interaction in perovskite, much weaker than in inorganic semiconductors. These weak many-body effects lead to a dephasing time in CH${}_3$NH${}_3$PbI${}_3$ $\sim$3 times longer than in GaAs. Our results also show that the strong enhancement of the exciton FWM signal tied to excitation-induced dephasing in GaAs and other III-V semiconductors does not occur in perovskite due to weak exciton-carrier scattering interactions.

Added 10 K results to previous version (Feb 16, 2016)

References in corpus (3)

• Direct Measurement of the Exciton Binding Energy and Effective Masses for Charge carriers in an Organic-Inorganic Tri-halide Perovskite
• Intrinsic femtosecond charge generation dynamics in a single crystal organometal halide perovskite
• Simultaneous observation of free and defect-bound excitons in CH3NH3PbI3 using four-wave mixing spectroscopy

Cited by in corpus (7)

• Perspective: Exciton polarons in two-dimensional hybrid metal-halide perovskites
• Exciton and Carrier Dynamics in 2D Perovskites
• Enhanced screening and spectral diversity in many-body elastic scattering of excitons in two-dimensional hybrid metal-halide perovskites
• Carrier Diffusion in Thin-Film CH3NH3PbI3 Perovskite Measured using Four-Wave Mixing
• Photon echo polarimetry of excitons and biexcitons in a CH${}_3$NH${}_3$PbI${}_3$ perovskite single crystal
• Ultrafast acoustic phonon scattering in CH${}_3$NH${}_3$PbI${}_3$ revealed by femtosecond four-wave mixing
• Exciton-exciton Interactions -- A Quantitative Comparison Between Complimentary Phenomenological Models