Electrical properties of inverted poly(3-hexylthiophene): Methano-fullerene [6,6]-phenyl C71-butyric acid methyl ester bulk hetero-junction solar cell with Cs2CO3 and MoO3 layers

We report the electrical properties of inverted P3HT:PC71BM bulk hetero-junction (IBHJ) with Cs2CO3 and MoO3 interlayers. The current density (J)–voltage (V) characteristics of the inverted P3HT:PC71BM bulk hetero-junction solar cells are studied, where MoO3 thickness is varied from 0.5 to 2 nm. The temperature independent, symmetric J–V characteristics in dark were found in the low bias voltage region between −0.35 and 0.35 V, and they exhibited the power law relationship J–V1.2 when the MoO3 thickness is between 1 and 2 nm. Open-circuit voltages at various light intensities of the IBHJ cell plotted as a function of absolute temperature converge to ∼0.965 V at zero temperature, which is very close to the energy difference between LUMO of PC71BM and HOMO of P3HT.