Third-Order Optical Nonlinearities in Organometallic Methylammonium Lead Iodide Perovskite Thin Films

• DOI: 10.1021/acsphotonics.5b00746
• Publication Date: 2016-02-02T20:40:13Z
• Authors: Basanth S. Kalanoor; Laxman Gouda; Ronen Gottesman; Shay Tirosh; Eynav Haltzi; Arie Zaban; Yaakov R. Tischler
• Keywords: Formamidinium; Nanosecond

With solar conversion efficiencies surpassing 20%, organometallic perovskites show tremendous promise for cell technology. Their high brightness has also led to demonstrations of lasing and power-efficient electroluminescence. Here we that thin films methylammonium lead iodide, prepared by solution processing at temperatures not exceeding 100 °C, exhibit a highly nonlinear intensity-dependent refractive index due changes in the free-carrier concentration femtosecond excitation higher intensities undergo saturation can be attributed Pauli blocking effect. Nonlinear absorption coefficients were obtained Z-scan technique, performed simultaneously open- closed-aperture configurations. Both nanosecond- femtosecond-pulsed lasers multiple wavelengths used order distinguish between mechanisms inducing nonlinearities. The magnitude sign n2 determined. For resonant excitation, free carrier generation is dominant contribution index, with large = 69 × 10–12 cm2/W being observed pumping 34.4 10–9 nanosecond pumping. nonresonant bound-charge-induced nonlinearity leads 36 cm2/W. These values are equivalent best reported metrics conventional semiconductors, suggesting promising materials optical switching bistability applications.