Interpretation of the Recombination Lifetime in Halide Perovskite Devices by Correlated Techniques.

The recombination lifetime is a central quantity of optoelectronic devices, as it controls properties such as the open-circuit voltage and light emission rates. Recently, the lifetime properties of halide perovskite devices have been measured over a wide range of the photovoltage, using techniques associated with a steady state by small perturbation methods. It has been remarked that observation of the lifetime is affected by different additional properties of the device, such as multiple trapping effects and capacitive charging. We discuss the meaning of delay factors in the observations of recombination lifetime in halide perovskites. We formulate a general equivalent circuit model that is a basis for the interpretation of all the small perturbation techniques. We discuss the connection of the recombination model to the previous reports of impedance spectroscopy of halide perovskites. Finally, we comment on the correlation properties of the different light-modulated techniques.