Seeking light sources from Si-based materials with an emission wavelength meeting the requirements of optical telecommunication is a challenge nowadays. It was found that the subband emission centered near 1200 nm can be achieved in phosphorus-doped Si quantum dots/SiO2 multilayers. In this work, we propose the phosphorus/boron co-doping in Si quantum dots/SiO2 multilayers to enhance the subband light emission. By increasing the B co-doping ratio, the emission intensity is first increased and then decreased, while the strongest integrated emission intensity is almost two orders of magnitude stronger than that of P solely-doped sample. The enhanced subband light emission in co-doped samples can be attributed to the passivation of surface dangling bonds by B dopants. At high B co-doping ratios, the samples transfer to p-type and the subband light emission from phosphorus-related deep level is suppressed but the emission centered around 1400 nm is appeared.

To enhance the efficiency of a solar thermophotovoltaic system, one of the challenges is to develop a thermal emitter with narrowband emission at a selected wavelength to efficiently match the bandgap of a bottom photovoltaic cell. Here, we propose a nanolayered narrowband thermal emitter with a-SiN x and a-SiN y O z alternatively stacked nanolayers deposited on a polished silicon substrate covered by metallic molybdenum. The fabricated Si-Mo-SiN x /SiN y O z emitters exhibit a good narrowband absorption with an absorptance of above 90% at the designed emission wavelength based on a Tamm plasmon polariton, while the absorption spectra can be tuned by simply changing the thickness of the multilayers. Due to the large imaginary part of the dielectric function of Mo as well as the better stability compared with tungsten (W), a suppressed absorption as low as 1.4% can be achieved within the wavelength region of 2–7 μm and the fabricated emitters exhibit a high resistance to high-temperature treatment in an air atmosphere. The simulated solar thermophotovoltaic system efficiency reaches 28.9% under a solar concentration of 1000 based on the proposed emitter. Such a nanolayered wavelength-selective thermal emitter can be potentially applied in high-performance thermophotovoltaic systems.

Developing a bifunctional electrocatalyst with remarkable performance viable for overall water splitting is increasingly essential for industrial-scale renewable energy conversion. However, the current electrocatalyst still requires a large cell voltage to drive water splitting due to the unsuitable adsorption/desorption capacity of reaction intermediates, which seriously hinders the practical application of water splitting. Herein, a unique SiO x /Ru nanosheet (NS) material was proposed as a high-performance electrocatalyst for overall water splitting. The SiO x /Ru NSs show superior performance in the hydrogen evolution reaction with a low overpotential of 23 mV (@ 10 mA cm −2 ) and excellent stability for nearly 200 h (@ 10 mA cm −2 ) in 1 M KOH. By means of the introduction of SiO x , it is beneficial for balancing the local charge density of the surrounding Ru sites. The suitable electronic coupling between the d-band electrons of Ru and the adsorbed species effectively balances the adsorption and desorption of reaction intermediates on the surface. As a result, the catalyst also exhibits overall water splitting activity with a cell voltage of only 1.496 V to reach the current density of 10 mA cm −2 . The present work opens up a new strategy for designing highperformance electrocatalysts for water splitting.