The effect of annealing treatment on performance of interdiffused organic photovoltaic devices

We fabricated the interdiffused organic photovoltaic devices, which composed of poly (2-methoxy-5-(2′-ethylhexyloxy)-1, 4-phenylen-evinylene) (MEH-PPV) and buckminsterfullerene (C60), by annealing treatment. After annealing, C60 diffused into the MEH-PPV layer, in consequence, MEH-PPV/C60 interfacial area was increased and their interface became closer proximity. The results lead to reduce reverse-bias saturation current (JS), and increase the open-circuit voltage (VOC) and the short-circuit current (JSC). Moreover, the increase in conductivity of poly (3, 4-ethylenedioxythiophene)/poly (styrenesulfonate) is also responsible for the performance improvement. Consequently, the power conversion efficiency is improved from 0.17% to 0.92% combined with the all increase of JSC, VOC and fill factor.