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

Figure 1

(a) Chemical structures of the two polymers, PTB7 and pBTTT. (b) Normalized UV-Visible absorption spectra (filled symbols) of films of PC₆₁BM, pBTTT, and PTB7 and corresponding PL spectra (open symbols) recorded upon excitation at 330 nm (PC₆₁BM), 535 nm (pBTTT), and 675 nm (PTB7) and (c) energy diagram of the ternary blend cells.

(a)

(b)

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