This study reveals the temperature dependence of absorption spectra for methylammonium lead iodide with specific attention for its sub-bandgap absorption edge (often referred to as Urbach energy). With this study we revealed:
- Clear evidence for the universality of the correlation between the Urbach energy and open-circuit voltage losses of solar cells.
- Small contribution of the static (temperature independent) part of the Urbach energy for CH3NH3PbI3 (3.8 ± 0.7 meV ) compared to other photovoltaic absorber technologies such as crystalline silicon (Si), gallium arsenide (GaAs), indium phosphide
(InP) or gallium nitride (GaN).
These implications underline the remarkable optoelectronic properties of perovskites.