Diffusion Enhancement in Highly Excited MAPbI Perovskite Layers with Additives.

Carrier mobility is one of the crucial parameters determining the electronic device performance. We apply the light-induced transient grating technique to measure independently the carrier diffusion coefficient and lifetime, and to reveal the impact of additives on carrier transport properties in wet-cast CHNHPbI (MAPbI) perovskite films. We use the high excitation regime, where diffusion length of carriers is controlled purely by carrier diffusion and not by the lifetime.