The charge stability of electret materials can directly affect the performance of electret-based devices such as electrostatic energy harvesters.In this paper,a spray-coating method is developed to deposit an electret...The charge stability of electret materials can directly affect the performance of electret-based devices such as electrostatic energy harvesters.In this paper,a spray-coating method is developed to deposit an electret layer with enhanced charge stability.The long-term stability of a spray-coated electret is investigated for 500 days and shows more stable performance than a spin-coated layer.A second-order linear model that includes both the surface charge and space charge is proposed to analyze the charge decay process of electrets in harsh environments at a high temperature(120°C)and high humidity(99%RH);this model provides better accuracy than the traditional deep-trap model.To further verify the stability of the spray-coated electret,an electrostatic energy harvester is designed and fabricated with MEMS(micro-electromechanical systems)technology.The electret material can work as both the bonding interface and electret layer during fabrication.A maximum output power of 11.72μW is harvested from a vibrating source at an acceleration of 28.5 m/s2.When the energy harvester with the spray-coated electret is exposed to a harsh environment(100°C and 98%RH),an adequate amount of power can still be harvested even after 34 h and 48 h,respectively.展开更多
基金supported by the Shenzhen Science and Technology Innovation Committee under Grants JCYJ20200109105838951 and JCYJ20170412154426330in part by Guangdong Natural Science Funds under Grants 2016A030306042 and 2018A050506001.
文摘The charge stability of electret materials can directly affect the performance of electret-based devices such as electrostatic energy harvesters.In this paper,a spray-coating method is developed to deposit an electret layer with enhanced charge stability.The long-term stability of a spray-coated electret is investigated for 500 days and shows more stable performance than a spin-coated layer.A second-order linear model that includes both the surface charge and space charge is proposed to analyze the charge decay process of electrets in harsh environments at a high temperature(120°C)and high humidity(99%RH);this model provides better accuracy than the traditional deep-trap model.To further verify the stability of the spray-coated electret,an electrostatic energy harvester is designed and fabricated with MEMS(micro-electromechanical systems)technology.The electret material can work as both the bonding interface and electret layer during fabrication.A maximum output power of 11.72μW is harvested from a vibrating source at an acceleration of 28.5 m/s2.When the energy harvester with the spray-coated electret is exposed to a harsh environment(100°C and 98%RH),an adequate amount of power can still be harvested even after 34 h and 48 h,respectively.
