Comment on "Resolving spatial and energetic distributions of trap states in metal halide perovskite solar cells".

Ni et al (Research Articles, 20 March 2020, p. 1352) report bulk trap densities of 1011 cm-3 and an increase in interfacial trap densities by one to four orders of magnitude from drive-level capacitance profiling of lead halide perovskites. From electrostatic arguments, we show that the results are not trap densities but are a consequence of the geometrical capacitance and charge injection into the perovskite layer.