Achieving milliwatt level solar-to-pyroelectric energy harvesting via simultaneous boost to photothermal conversion and thermal diffusivity

Pyroelectric technology is an effective strategy to harvest ambient waste heat into electrical energy to tackle global energy and environmental crises. However, current pyroelectric generators are often limited by low effective power output. Herein, we develop a non-contact, solar-induced pyroelectric nanogenerator (S-PENG) which integrates Au@CNT as solar-thermal layer and polarized PVDF film as pyroelectric layer. The high thermal conductivity of CNT accelerates the heat transfer process, while its strong solar-thermal effect can be coupled with the plasmonic effect of Au nanoparticles to obtain a hybrid ensemble with superior light absorption and conversion. Notably, the solar-thermal temperature of Au@CNT/PVDF rapidly increases from 38 °C to 79.6 °C within 30 s under sunlight irradiation, with a corresponding temperature change rate reaching a maximum of 14.3 °C/s. The drastic temperature fluctuation is crucial to improve the output performance of our S-PENG. More importantly, our S-PENG successfully generates a notable 1.5 mW/m² output power under a 200 MΩ load (at 20 ℃), thereby overcoming the performance bottleneck of traditional S-PENG designs with micro-watt power output. Our design offers a promising approach to efficiently utilize green solar energy to alleviate our demand on limited energy resources and reduce carbon footprint.