Recently, flexible thermoelectric generator (FlexTEG) modules using organic or thin film materials have gained much attention due to their potential applications for, for example, wireless sensors and wearable power. However, the performance of these modules is poor and still far from the requirement for energy harvesting. Here, the traditional semiconductor packaging technique is adapted to fabricate a large‐scale FlexTEG, for use in energy harvesting on both planar and nonplanar surfaces. The module uses high‐performance bismuth‐telluride p‐ and n‐type chips on a flexible thin plastic substrate. Using a unique isotropic design for mounting the chips, a FlexTEG module consisting of 250 p‐n pairs is successfully fabricated on a 50 × 50 mm2 flexible substrate. The output power, mechanical strength, and bending properties are investigated at different temperature gradients and bending cycles. The module exhibits a maximum output power density of 158 mW cm−2 at dT = 105 K, corresponding to an efficiency value of 1.84%, which is comparable to a conventional bulk TEG. Mechanical tests reveal that the flexible module is reliable and stable during bending. These results open great potential for applications in portable, wearable, or implantable electronic devices.

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The metal-organic decomposition (MOD) method, which is a nanoscale film-forming process, has attracted much attention as the next generation of advanced coating techniques. Functional thin films of metals and metal oxides, especially nanostructural materials, are required to be formed on any substrate through reduced raw materials/resources, while also saving energy and using low-cost materials in the fabrication process. In this study, titanium dioxide (TiO2) nanocrystalline structure thin films have been directly synthesized successfully while also demonstrating growth on the substrate using the MOD method, a process combining the coating and heat sintering or photosintering. We obtained two kinds of dendrimerlike and spherelike nanostructural morphologies as TiO2 at low temperatures in both the heating and photosintering techniques through the capping and redaction effects of stabilizers in our two precursors. In particular, metal oxides film formed successfully on plastic substrate without any damage to the substrate. The gas sensor device from the spherelike TiO2 nanostructure by the MOD method shows an excellent high-speed gas-sensing response and recovery time because the TiO2 nanocrystal structures have a large surface area and a highly crystalline structure, which are useful for applications in both universal electronic devices and gas sensors.

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