XRD curves of VOPc thin films grown on the ITO substrate. Curve a: 80-nm VOPc pristine thin film, curve b: 160-nm pristine thin film, curve c: 160-nm VOPc with a post-treatment at 255 °C for 2 hours, curve d: VOPc thin film treated at 275 °C for 2 hours, curve e: VOPc deposited at the substrate with a temperature of 180 °C, and curve f: VOPc deposited at the substrate with a temperature of 250 °C.