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.

Graphical abstractJ–V characteristics in dark of IBHJ solar cells with various MoO3 thicknesses in the temperature range of 180–300 K.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Electrical properties of P3HT:PC71BM IBHJ solar cells with Cs2CO3 and MoO3 interlayers. ► Temperature independent, symmetric J–V characteristics in dark. ► Power law relationship J–V1.2 due to the tunneling effect via MoO3 interlayer. ► Cs2CO3 and MoO3 interlayers are confirmed using TEM–EDS. ► Maximum VOC is ∼0.965 V.