High Mobility Low Temperature Processed Inkjet Printed Flexible MoS₂ Transistors on Sustainable Flexible Substrate

The exponential growth of modern electronic devices including smartphones, wearables, and flexible displays has resulted in a global surge of electronic waste, projected to reach 74.7 million tons by 2030. This growing crisis not only strains natural resources but also poses serious risks to the environment, human health, and data security. Hence, the development of eco-friendly, transient electronic devices capable of controlled degradation is of growing importance. Herein, we demonstrate a sustainable approach to fabricate the field-effect transistor (FET) by integrating green materials into key device components. Polyvinyl alcohol (PVA), a biodegradable synthetic polymer with excellent film-forming properties, has been employed as the substrate, while molybdenum disulfide (MoS₂), a biocompatible two-dimensional semiconductor, served as the active layer. A solvent engineering strategy is introduced to overcome the challenge of surfactant and solvent residues that typically hinder charge mobility in solution-processed MoS₂ films. The use of green solvents enabled effective removal of PVP residues, leading to high performance transistors with a maximum mobility of 74.9 cm² V⁻¹ s⁻¹, an on-current of 1.01 mA, and an on/off ratio of 1.96 × 10⁶ at 150 °C on flexible polyimide substrates. Importantly, it has helped in fabricating devices at a very low processing temperature of 75 °C with excellent mobilities up to 1.99 cm² V⁻¹ s⁻¹ and on/off ratios of 1.15 × 10⁵. Such a low processing temperature allowed the device fabrication on a biodegradable PVA substrate demonstrating reasonable device characteristics (mobility of 0.093 cm² V⁻¹ s⁻¹ and on/off ratios of 1.15 × 10⁵). Additionally, these devices have been subjected to biodegradability study with different buffer solutions which exhibits good degradation in basic solution < 90 day when compared to the acidic solution. Furthermore, the fabricated transistors have been integrated into basic logic circuits, including depletion mode inverters and NAND, NOR, AND, and OR gates, all operating reliably at 1 kHz. These findings establish a viable route toward green, low-cost, and energy-efficient MoS₂-based electronics, contributing to sustainable device technologies that minimize e-waste and environmental impact.