Effect of ZnO nanoparticles on the power conversion efficiency of organic photovoltaic devices synthesized with CuO nanoparticles.

Polymer solar cells were fabricated with varying amounts of electron transporting ZnO NPs in a buffer layer located over an active layer of P3HT/PCBM incorporating a fixed amount of CuO nanoparticles. The enhanced electronic and optical properties attained by adding ZnO nanoparticles proportionally increased the power conversion efficiency by 32.19% compared to a reference cell without ZnO-NPs buffer layer. ZnO-NPs buffer layer improved the exciton dissociation rate, electron mobility, optical absorption and charge collection at the anode, resulting in higher short circuit current and external quantum efficiency. The short circuit current (Jsc) of the optimum device was measured at 7.620 mA/cm2 compared to 6.480 mA/cm2 in the reference cell with 0.6 mg of CuO nanoparticles. Meanwhile, the external quantum efficiency (EQE) increased from 54.6% to 61.8%, showing an enhancement of 13.18% with the incorporation of ZnO nanoparticle layer. [ABSTRACT FROM AUTHOR]