We demonstrate that lossy plasmonic resonances of nanoparticles are broad enough to cover the majority of the solar spectrum and highly efficient for absorbing sunlight. In analytical calculation, we choose a titanium nitride nanoparticle as a lossy plasmonic nanoresonator and present that sunlight absorption efficiency of a titanium nitride nanoparticle is higher than gold and even black carbon nanoparticles. The experiments demonstrate that titanium nitride nanoparticles dispersed in water have high efficiency to heat water and generate vapor than carbon nanoparticles by converting sunlight into heat. Our results open great possibilities for efficient solar heat applications with titanium nitride nanoparticles.

We report the fabrication of titanium nitride (TiN) films with the “best” plasmonic behavior reported so far by the pulsed laser deposition method. Even though the deposition is done at room temperature (∼25 °C) and grown on an amorphous native oxide of a silicon wafer, the plasmonic property of the TiN is comparable to that of gold, which is a conventional plasmonic material in the visible to near-infrared region. Because of the highly plasmonic nature of the TiN, the near field around the TiN nanostructure can be as high as that of a gold nanostructure. A room-temperature process without a strict requirement on the substrate allows depositing a TiN film even on a flexible polymer film without degrading its property. Our results pave the way for using TiN as a truly practical plasmonic material, replacing the use of noble metals.

We demonstrate a hybrid plasmonic−pyroelectric device operating as an uncooled midwavelength infrared detector with narrowband spectral selectivity. The device consists of a plasmonic perfect absorber with a built-in pyroelectric ZnO layer: It consists of a ZnO layer sandwiched by a Au microhole array as a top electrode and a Pt bottom electrode as a template for the uniaxially grown ZnO film. The geometrical design of the plasmonic Au (hole array)/ZnO/Pt system is determined by the numerical electromagnetic simulation and then fabricated by colloidal-mask lithography combined with reactive-ion etching. The fabricated detectors exhibit excellent spectral selectivity at the predesigned plasmonic resonances, which are tunable by changing the Au hole diameters. The results obtained here open up a route for realizing a new type of uncooled spectroscopic infrared detectors with a compact design and simple fabrication process.

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We propose analytically and demonstrate experimentally that an ensemble of silicon nanoparticles with different sizes can effectively absorb sunlight. Due to the extinction of silicon from UV to near-infrared region, Mie resonances in silicon nanoparticles dramatically enhance the absorption of solar light. In experiment, silicon nanoparticles dispersed in water worked as excellent sunlight-heat transducers that efficiently harvest sunlight to accelerate heating and vaporization of water by nanoscale local heating. Our study opens up the potential of silicon nanoparticles in various solar-thermal applications.

In this work, a promising strategy to increase the broadband solar light absorption was developed by synthesizing a composite of metal-free carbon nitride-carbon dots (CN-C dots) and plasmonic titanium nitride (TiN) nanoparticles (NPs) to improve the photoelectrochemical water-splitting performance under simulated solar radiation. Hot-electron injection from plasmonic TiN NPs to CN played a role in photocatalysis, whereas C dots acted as catalysts for the decomposition of HO to O. The use of C dots also eliminated the need for a sacrificial reagent and prevented catalytic poisoning. By incorporating the TiN NPs and C dots, a sixfold improvement in the catalytic performance of CN was observed. The proposed approach of combining TiN NPs and C dots with CN proved effective in overcoming low optical absorption and charge recombination losses and also widens the spectral window, leading to improved photocatalytic activity.

We report on multifunctional devices based on CNT arrays-ZnO nanowires hybrid architectures. The hybrid structure exhibit excellent high current Schottky like behavior with ZnO as p-type and an ideality factor close to the ideal value. Further the CNT-ZnO hybrid structures can be used as high current p-type field effect transistors that can deliver currents of the order of milliamperes and also can be used as ultraviolet detectors with controllable current on-off ratio and response time. The p-type nature of ZnO and possible mechanism for the rectifying characteristics of CNT-ZnO has been presented

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