Effect of Annealing Temperature and MoO3 Composition on the Mechanical Properties of PEDOT:PSS-MoO3 Blend Thin Film Layers for Organic Solar Cells and Organic Light Emitting Diodes Applications

Experimental and computational methods are employed in this study to examine how varying heat treatment temperatures and composition of Moo3nanoparticles, a transition metal oxide (TMO) impact the mechanical properties of PEDOT:PSS/MoO3 thin film blends for organic photovoltaics (OPVs) and organic light emitting diode (OLED) applications. The study primarily investigates the mechanical properties (hardness and Young's modulus), microstructure and surface morphology of solution-processed PEDOT:PSS/MoO3 ink blends of different compositions prepared at temperature regimes between 60 to 120 °C. Nanoindentation is used to investigate mechanical properties and Scanning Probe Microscopy to examine the surface morphological and microstructural changes. Mechanical maps and statistical deconvolutions are used to show the distribution of mechanical properties and phases respectively in the PEDOT:PSS/Mo03 thin film blends at the different annealing temperatures (60 - 120 °C). The experimental and computational results lead to the conclusion that incorporating different percentages of Moo3into PEDOT:PSS can, depending on the blended ratio improve the microstructure, mechanical properties and surface morphology of the PEDOT:PSS/MoO3 blends. Lightly doped PEDOT:PSS/MoO3 blends (1:0.1, 1:0.3), generally exhibit improved surface morphologies, enhanced elastic modulus and hardness, suitable for applications in efficient and mechanically durable electronic devices.