Fig. 5From: Perovskite Solar Cells Fabricated by Using an Environmental Friendly Aprotic Polar Additive of 1,3-Dimethyl-2-imidazolidinone a Nyquist plots of the perovskite solar cells in the dark at a bias of 0.9 V. b Steady PL spectra of the perovskite films. c Time-resolved PL spectra basing on the bi-exponential decay function fabricated from three different conditionsBack to article page