Figure 4. Photovoltaic characterization of polymer-scaffold perovskite solar cells.

(a) J–V curves of the reverse scan based on precursor solution with different PEG molecular weight (concentration: 20 mg ml⁻¹) measured from 1.5 to −0.2 V under 500 mV s⁻¹. (b) J–V curves of the reverse scan based on precursor solution with different PEG concentration (molecular weight: 20,000 Da) measured from 1.5 to −0.2 V under 500 mV s⁻¹. (c) Recombination time constant R_rec.C_rec (R_rec, recombination resistance, C_rec, capacitance) under different applied voltage can be extracted by fitting the Nyquist plot using the inset circuit. (d) PCE distribution of perovskite solar cells with (20 or 40 mg ml⁻¹) and without PEG scaffold. PCE values are extracted from reverse scan curve measured from 1.5 to −0.2 V under 500 mV s⁻¹. The active area for testing is 9 mm².