Research On Ultra-broadband Solar Energy Capture And Ultra-narrowband Optical Sensor Based On Metal-dielectric Multilayer Structure

Modern optoelectronic information technology requires more and more miniaturization and integration of devices.Ultra-compact and miniaturization has become an inevitable trend in the development of optoelectronic technology.The micro/nano structures based on metal-dielectric composites show many unique optical properties,such as broadband optical absorption,extraordinary optical transmission and electromagnetic field enhancement,which have great application prospects in the field of optoelectronic technology,and have become one of the research hotspots in recent years.In this paper,we have constructed several metal-dielectric multilayer nanostructures with perfect ultra-broadband and ultra-narrowband optical absorption/transmission performance,and further explored their applications in the field of solar energy capture and high-quality optical sensing.It mainly includes the following contents:?1?A kind of metal-dielectric composite multilayer ultra-broadband absorber based on refractory materials was constructed.The absorber is composed of the grating structure of insulator-metal-insulator?IMI?and the film stacking structure of metal-insulator-metal?MIM?.Due to the synergistic effects of guided mode resonance,surface plasmon polaritons and cavity mode,the absorber exhibits near perfect optical absorption in the 570 nm-3539 nm band and the average optical absorption rate is over 97%.Moreover,only titanium?Ti?and alumina?Al₂O₃?with high melting point are used in the absorber,which provides a good guarantee for the thermal stability of the absorber.In addition,when the incident angle increases from 0°to 50°under different polarization,the absorption rate of the absorber is still higher than 80%.These advantages make this ultra-broadband near perfect optical absorber have great potential in the fields of solar thermal energy collection,thermoelectric components and imaging.?2?A three-layer broadband absorber based on GaAs grating is constructed.The structure consists of the top layer of GaAs grating,the interlayer of GaAs film and the substrate of W film.The absorber has a broadband near perfect optical absorption in the band of 506 nm-1814 nm,with an average absorption rate of 97%.The solar energy capture performance is superior.This broadband absorption phenomenon is due to the interaction between the excited metal surface plasmon polaritons and the dielectric cavity mode.In addition,the ideal short-circuit current of the absorber is as high as 56 MA/cm².These features provide new ideas for the realization of ultra-thin solar cells,solar energy collection,magnetic recording,ultra-thin and durable photoelectric elements.?3?Based on the research results of?2?,we further optimized the structure system,and constructed a five layer composite structure of ultra-broadband absorber assisted by semiconductor grating.The structure of the device is to stack the semiconductor grating on the metal semiconductor metal film layer,and stack the antireflection coating made of indium tin oxide on the top of the grating.In the 468nm-2870 nm band,the optical absorption rate of the absorber is over 95%and the ideal short-circuit current is as high as 61 MA/cm²,which proves that the absorber has nearly perfect solar light capture ability.At the same time,the absorber also shows good independence of incident angle and polarization angle.These provide new ideas for the realization of ultra-compact and efficient photovoltaic cells and heat emitters,and lay a foundation for the better development of metal dielectric composite multilayer structure.?4?A multi-frequency ultra-narrowband optical sensor based on light transmission is proposed.The structure is formed by stacking a layer of dielectric grating on the stack layer of the semiconductor-metal-semiconductor?SMS?film.Due to the simultaneous effects of propagating surface plasmon polaritons,guided mode resonance and cavity modes.There are three ultra-narrow resonant transmission dips in the transmission spectrum of the structure,the minimum half width at half maximum?FWHM?is only 5 nm,the maximum refractive index sensitivity?S?is 654nm/RIU,and the maximum figure of merit?FOM?reached 130.8.The structure can be used to detect protein molecular layers with sub-nanometer thickness,which provides a new perspective for the realization of ultra-miniature and efficient sensors and filters.