Enhanced Efficiency of PTB7 : PC₆₁BM Organic Solar Cells by Adding a Low Efficient Polymer Donor

Figure 5

AFM topographic and phase images (1 × 1 μm²) of (a) PTB7 : PC₆₁BM (1 : 2); (b) pBTTT : PC₆₁BM (1 : 2); (c) ternary blend films of PTB7 : pBTTT : PC₆₁BM with 25 wt% of pBTTT replacing PTB7. All the films were prepared onto glass/ITO/PEDOT : PSS substrates. (d) of the various films as a function of pBTTT content (wt%).

(a) PTB7 : PC₆₁BM (1 : 2)

(b) pBTTT : PC₆₁BM (1 : 2)

(c) PTB7 : pBTTT : PC₆₁BM (0.75 : 0.25 : 2)

(d)