Ultrafast All-Optical Modulation and Efficient Third-Harmonic Generation in Two-Dimensional Perovskite Heterostructures

Ultrafast all-optical modulation and efficient frequency conversion are highly required for a wide range of applications including optical communication, microwave photonics, and quantum computing. However, the ultrafast and efficient light–matter interactions are challenging for the available optoelectronic materials. Here, we demonstrate the solution-processable two-dimensional halide organic–inorganic perovskite (2D HOIP) heterostructures can exhibit ultrafast all-optical modulation and efficient third-harmonic generation experimentally. We fabricated 2D HOIP heterostructure film (PEA)2PbI4/(PEA)2(MA)2Pb3I10 by a one-step spin-casting method and found that the heterostructures can produce efficient third-harmonic emission with larger conversion efficiency (η = 2 × 10–5) than other typical perovskites and two-dimensional materials. In addition, the time-resolved transient absorption spectroscopy reveals the transfer path of photocarriers in perovskite heterostructures, while sub-picosecond ultrafast relaxation and ∼−4.85% nonlinear absorption modulation have been observed at the band edge. Our results suggest that 2D HOIP heterostructures can serve as an ideal platform for nonlinear optical modulation and wavelength conversion and may pave the way for developing high-performance cost-effective ultrafast optoelectronic devices.