Fig. 7. (a) Photocurrent density (J_ph) versus effective voltage (V_eff) for the solar cells doping with 0 wt% and 5 wt% PbS QDs, (b) time-resolved photoluminescence spectra of PTB7:PC₇₁BM blend film with 0 wt% and 5 wt% PbS QDs, the emission at 750 nm was recorded after excitation at 450 nm.