Effect of casting process of polymer active layer on performances of polymer solar cells

Abstract

Hole mobility of poly［2-methoxy-5-（2′-ethylhexyloxy）-1，4- phenylenevinylene］ （MEH-PPV） film fabricated by spin-casting and drop-casting has been measured by time-of-flight （TOF） technique. The non-dispersive hole transport current waveform is obtained. The results exhibit that the hole mobility of MEH-PPV prepared by drop-casting is higher than that of the film prepared by spin-casting. The solar cells based on MEH-PPV and fullerene derivative blend films prepared by spin-casting and drop-casting，respectively，were fabricated. The power-conversion efficiency （PCE） of the drop-casting device has a great improvement of over 35%，compared with that of spin-casting one. The improvement is attributed to the stronger absorption and better balance of electron and hole transport in MEH-PPV polymer films.