Research Article

A PCBM-Modified TiO2 Blocking Layer towards Efficient Perovskite Solar Cells

Figure 3

SEM photographs of TiO2 thin films prepared at (a) 2000 rpm, (b) 4000 rpm, and (c) 6000 rpm, respectively. And SEM photographs of CH3NH3PbI3−xClx on TiO2/PCBM thin films, with TiO2 prepared at 4000 rpm and PCBM at (d) 2000 rpm, (e) 4000 rpm, and (f) 6000 rpm.
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