Plasmon-enhanced optical photodiodes based on MEH-PPV polymer and fullerene blend on ITO

We report the fabrication of silver plasmon-enhanced photodiodes with a single active layer sandwich mixture, using ITO with Ag nanoparticles and poly (2-methoxy-5-(20-ethylhexyloxy)- 1,4-phenylenevinylene) (MEH-PPV):fullerene-C60 blend. Ag nanoparticles were created first by ebeam depositing 20 Å of Ag on ITO followed by RTA annealing under nitrogen at 250 °C for 30 min. Devices were fabricated using spin casting the blend over the ITO/Ag nanoparticles. After baking, Al metal was deposited on top of MEH-PPV fullerene-C60 blend using e-beam evaporation for the metal contacts. We observed enhanced absorbance due to the Ag nanoparticles and increased photo response by the fabricated photodetector. I-V characterization allowed us to determine the barrier height, diode ideality factor, and series resistance. The diode shows a non-ideal I-V behavior due to a high probability of electron and whole recombination in the depletion region or existence of tunneling current, or perhaps due to the presence of interfacial layer or series resistance. The photocurrent and the photoconductive behavior indicate that these devices can be used as solar cells.