Fig. 2: Hole concentration enhancement in the perovskite film through additive engineering.
a, A schematic diagram of controlling the amount of additives by the IPA washing method. b, The calculated JDOS of these configurations with different additive densities to illustrate the corresponding change in absorption characteristics after IPA wash. c,d, Absorption (c) and UPS spectra (d) of the pristine film and the film after IPA washing at room temperature. e, UPS spectra of the pristine film at room temperature (RT) and low temperature (LT) (~80 K).
