This study presents fully inkjet-printed Ag₂Se-based flexible thermoelectric devices for sustainable power generation. The researchers developed Ag₂Se-based thermoelectric films and flexible devices using inkjet printing, achieving high-resolution patterns with microscale resolution. The printed Ag₂Se-based films exhibit an exceptional power factor of 1097 μW m⁻¹ K⁻² at 377 K, which is more than five times that of state-of-the-art inkjet-printed materials. The devices achieve a record-high normalized power of 2 μW K⁻² cm⁻² and superior flexibility, with the ability to survive 3,000 bending tests at bending radii of 3–4 mm. The devices can be used for continuous power generation by harvesting thermal energy from the environment or human bodies. The study highlights the advantages of inkjet printing in fabricating flexible thermoelectric devices, including low cost, high resolution, and scalability. The Ag₂Se-based inks used in the study are highly printable and stable, with excellent processability and stability. The inkjet printing process allows for precise control of the deposition of micro- and nanomaterials, enabling the creation of complex and versatile thermoelectric legs. The devices are fabricated using a combination of Ag electrodes and Ag₂Se/Ag composite legs, with the Ag₂Se/Ag composite film showing a power factor of 1097 μW m⁻¹ K⁻² at 377 K. The study also demonstrates the potential of inkjet-printed Ag₂Se-based flexible devices for various applications, including solar thermal/thermoelectric/radiative cooling (STR) hybrid devices that can generate power from environmental and human body heat. The devices are highly flexible and can be integrated into wearable and implantable electronics, offering a sustainable power source for energy-autonomous systems. The research shows that inkjet printing is a promising technique for the design and fabrication of flexible thermoelectric devices, with the potential to revolutionize the field of sustainable power generation.This study presents fully inkjet-printed Ag₂Se-based flexible thermoelectric devices for sustainable power generation. The researchers developed Ag₂Se-based thermoelectric films and flexible devices using inkjet printing, achieving high-resolution patterns with microscale resolution. The printed Ag₂Se-based films exhibit an exceptional power factor of 1097 μW m⁻¹ K⁻² at 377 K, which is more than five times that of state-of-the-art inkjet-printed materials. The devices achieve a record-high normalized power of 2 μW K⁻² cm⁻² and superior flexibility, with the ability to survive 3,000 bending tests at bending radii of 3–4 mm. The devices can be used for continuous power generation by harvesting thermal energy from the environment or human bodies. The study highlights the advantages of inkjet printing in fabricating flexible thermoelectric devices, including low cost, high resolution, and scalability. The Ag₂Se-based inks used in the study are highly printable and stable, with excellent processability and stability. The inkjet printing process allows for precise control of the deposition of micro- and nanomaterials, enabling the creation of complex and versatile thermoelectric legs. The devices are fabricated using a combination of Ag electrodes and Ag₂Se/Ag composite legs, with the Ag₂Se/Ag composite film showing a power factor of 1097 μW m⁻¹ K⁻² at 377 K. The study also demonstrates the potential of inkjet-printed Ag₂Se-based flexible devices for various applications, including solar thermal/thermoelectric/radiative cooling (STR) hybrid devices that can generate power from environmental and human body heat. The devices are highly flexible and can be integrated into wearable and implantable electronics, offering a sustainable power source for energy-autonomous systems. The research shows that inkjet printing is a promising technique for the design and fabrication of flexible thermoelectric devices, with the potential to revolutionize the field of sustainable power generation.