Figure 4

(a) J-V characteristics and (b) EQE spectra of PTB7-Th:PC₇₁BM based PSCs using p- and fZnO NPs as ETLs comparing with as-prepared and aged for 2 months of each NPs. (c) J–V characteristics and (d) EQE spectra of PTB7-Th:IEICO-4F and PBDB-T:IT-M based PSCs with fZnO NPs as ETLs.