Fig. 2: Electro-optical characteristics of CsPbBr₃ QD-based LEC.

a Schematic illustration of ion migration inducing electric dipoles aligning along the direction of an applied electric field. Cations and anions are hence accumulated close to the Ag and ITO electrodes, respectively, leading to the formation of the p-i-n diode. b I–V characteristics of the perovskite LEC for the sweep voltage range of 0 V → 8 V → 0 V, and a clear hysteresis effect is observed in this figure. Inset: the corresponding energy-level diagram while applying a negative poling voltage on the LEC (Ag: cathode; ITO: anode). c Same as b, but plotted in a semi-log scale. Insets: the modified Shockley equation (top) and a summary table of the turn-on voltage, series and shunt resistances extracted from the forward and reverse I-V characteristics (bottom). d EL intensity of the perovskite LEC versus sweeping voltage in a range of 0 V → 8 V → 0 V. Insets show the images of the LEC under forward (left) and reverse (right) voltages of 4, 6, and 8 V. e and f Evolutions of EL spectra with the increase of forward and reverse voltages. The peak wavelength (λ_P) and the spectral bandwidth (FWHM) extracted from the EL spectra as a function of voltage are also inserted in both figures.