Characterisation of the Electronic Properties of Biodegradable Organic Semiconductor Films for Flexible Electronics Applications

Background: Biodegradable organic semiconductors address growing electronic waste concerns by enabling devices that can safely degrade after use. Their electronic property characterisation under tropical humidity conditions relevant to Nigerian deployment is a critical research gap. Aim: This study characterised the electronic properties of selected biodegradable organic semiconductor films, including beeswax and shellac-derived composites, for flexible electronics applications under ambient Nigerian climatic conditions. Methods: Thin films were deposited by thermal evaporation on flexible PET substrates. Organic field-effect transistors were fabricated and characterised for carrier mobility, on-off current ratio, and threshold voltage using standard transfer and output characteristic measurements. Stability under 85% relative humidity and 35 degrees Celsius conditions was assessed over 60 days. Results: Maximum hole mobility of 0.12 cm2/Vs was achieved for the optimised shellac composite film. On-off current ratios exceeded 105. Carrier mobility degraded by 31% after 60 days of humidity exposure, compared with 68% degradation for standard OFET reference films. Conclusion: Biodegradable organic semiconductor films show adequate performance for low-speed flexible electronic applications while demonstrating superior humidity resilience compared with conventional organics. Further encapsulation strategies are recommended to extend operational lifetime in tropical conditions. Keywords: organic semiconductor, biodegradable electronics, flexible electronics, OFET, tropical humidity.