Investigation of the optical, morphological and structural properties of molybdenum trioxide (MoO3) and zinc oxide (ZnO) thin film layers used in inverted organic solar cells

Abstract

In this study, optical, morphological and structural properties of inverted organic solar cell structure such as the electron transport layer and hole transport layer was examined. Molybdenum trioxide (MoO3) was used as a hole transport layer (HTL) in an inverted structure while zinc oxide (ZnO) used as an electron transport layer (ETL) in the same structure. Firstly, the chemical cleaning of glass was done. After, 0.5 g zinc acetate dihydrate was dissolved in 6.38 ml ethanol and zinc oxide (ZnO) solution was obtained. Zinc oxide (ZnO) solution was filtered using an 0.45 ɥm PVDF filter. Then, ZnO solution was coated on glass surfaces by spin coating at 2500 rpm for 50 sec followed by annealing at 150 °C for 10 min on a hot plate in ambient. Secondly, 10 nm thick molybdenum trioxide (MoO3) was coated on the glass surfaces using thermal evaporation at a pressure of 5 × 10−7 Torr and an evaporation rate of 1 Å/sec in the glove box system. XRD, SEM, AFM, thickness and absorption measurements of these thin films coated on glass surfaces were performed. In the next stage, fabrication and characterization of ITO/ZnO/P3HT:PCBM/MoO3/Al inverted organic solar cells structures will be performed using these films.