Facile fabrication of UV photodetectors using spin-coating flame-synthesized ZnO nanoparticles

A facile and direct spin-coating technique was employed in the synthesis of UV photodetectors utilizing flame-made, highly crystalline ZnO nanoparticles (NPs) deposited on glass substrates. The morphological and microstructural analysis revealed that this nonchemical reaction-based spin-coating approach can generate homogeneous ZnO thin films with tunable thickness, possessing an average porosity of 80%, which is significantly higher compared to conventional spin-coated films. With the coating cycles increasing from 2 to 15 times, the size of ZnO NPs slightly increases. With 10 cycles, spin-coated ZnO UV photodetector exhibits the highest responsivity of 74 mA W^-1 under a fixed bias of 3.3 V. A proportional constant of ∼22.6 μA cm^-1 °C^-1 is observed for the photocurrent variation as the working temperature changes. All prepared ZnO UV photodetectors exhibited fast response dynamics, with a response time of about 1 s and a recovery time of less than 4 s, while maintaining excellent stability and repeatability, making them promising candidates for wearable technologies and personalized devices.

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