Self-adaptive Radiative Cooling Based On Compound Cross-structure Metasurface

Nowadays,with the advent of the energy era,radiative cooling technology has developed rapidly.At the meanwhile,the energy problem has been put on the stage of competition for resources around the world,and it has gradually become fierce.The use of mainstream energy sources is still based on the continuation of traditional non-renewable energy sources.A large amount of use of these energy sources will inevitably lead to their endangerment.Finding new alternative energy sources and saving existing energy sources before they are exhausted has undoubtedly become the current research work Issues that need urgent research.The energy consumption caused by indoor appliances(such as refrigerators,air conditioners,etc.)and some outdoor structures(such as cars,buildings,etc.)has led to problems such as energy shortages and global warming.Hence,we can start from here,to find ways decreasing the thermal consumption.Radiative cooling and solar heating are two types of optical thermal effects.The object completely radiates its own heat to the absolute zero space of outer space through the form of radiated electromagnetic waves to achieve the purpose of heat dissipation.Similarly,it can also achieve the effect of heating by absorbing as much solar energy as possible in places with strong solar radiation.Photothermal management is achieved by controlling the photothermal effect of materials to adjust their light absorption performance in different bands.It plays a vital role in the thermal behavior of energy consumption in outdoor structures.If the solar heating efficiency and radiative cooling efficiency of the material can be adjusted,the photothermal management of the material can be realized,thereby saving energy consumption.In this subject,based on the thermal effect of organ gels and the principle of high-sensitivity plasmon resonance,we propose a conceptual new design of adaptive photothermal management through adjustable radiative cooling and solar heating.These absorption spectra correspond to different working bands and are independently adjusted by the large cross structure absorber and the small cross structure absorber.Finally,the composite metasurface composed of the two types of harmonic absorbers can be adaptive in one system to realize radiative cooling and solar heating effect.We can see from the results,the system can contribute more than 41.1% and 32% of the effectiveness for heating and cooling,respectively.This paper conducts research work to achieve tunable radiative cooling and solar heating.The main research contents and conclusions are as follows:1.A conceptual photothermal management system is proposed,which combines the superposition of different structures to achieve a combination of two independent control functions.Combining the use of thermally effective polymer film layers to prepare composite metasurface structures to achieve temperature-controlled automatic conversion of cooling and heating functions.2.Based on the finite difference time domain(FDTD)method,a verification analysis of the light absorption effect of the design prototype was performed,which proved that the carefully designed cross structure is able to show the functional characteristics of a perfect absorber.Through the study of different geometric parameters of the structure,the key parts affecting the radiant cooling and solar heating efficiency of the absorber are summarized.3.Using FDTD Solutions software to change the parameter settings of key parts of the structure in a timely manner to obtain the optimal geometric size.According to the different target functions,analyze and verify the effects of different structural pins,and confirm that the two functions will not affect each other.4.Samples in a single state were prepared experimentally.Electron beam lithography and focused ion beam etching are used for microstructure processing.Electron beam evaporation and magnetron sputtering methods are used to deposit metal and dielectric films.Atomic force microscope and electron microscope are used to characterize the structure thickness and morphology of the sample.And the additional energy dispersion spectroscopy equipment is used to measure and analyze the spectral characteristics of the sample.5.The calculation of the thermal properties of the simulated structure proves that the composite cross metasurface structure used in this article in combination with a polymer with thermal effects can achieve the function of dynamic adaptive temperature regulation(cooling when the temperature is high and heating when the temperature is low).At present,the problems of low efficiency conversion and experimental processing still exist,and further research can be continued around improving efficiency and large-scale applications in the future.