Selective thermal emitters concentrate most of their spontaneous emission in a spectral band much narrower than a blackbody. When used in a thermophovoltaic energy conversion system, they become key elements defining both its overall system efficiency and output power. Selective emitters' radiation spectra must be designed to match their accompanying photocell's band gap and, simultaneously, wi...

Nonclassical quantum effects gradually reach domains of physics of large systems previously considered as purely classical. We derive a hierarchy of operational criteria suitable for a reliable detection of nonclassicality of light from an arbitrarily large ensemble of independent single-photon emitters. We show, that such large ensemble can always emit nonclassical light without any phase refe...

The properties that govern the production and escape of hydrogen ionizing photons (Lyman continuum, LyC; with energies >13.6 eV) in star-forming galaxies are still poorly understood, but they key to identifying characterizing sources reionized Universe. Here we empirically explore relationship between hardness radiation LyC leakage a large sample low-$z$ from recent Hubble Space Telescope Low-$...

This review reflects the status (in early 1973) of the problem of producing photoemitters and secondary and field emitters based on a new principle, that of obtaining semiconductor structures with negative electron affinity (ΝΕΑ). The energy level scheme of the surface region of a semiconductor with ΝΕΑ is examined, as well as the conditions for its realization. The main theoretical concepts of...

Longitudinal sections of human cortical bone were submitted to thermal neutrons. gamma-ray spectra were recorded repeatedly during 15 days following irradiation. They showed that Na(24) is predominant as early as 3 hours after activation and that all the gamma-emitters have decayed on the 15th day. When the gamma-rays have disappeared, beta-rays are still produced by the sections. It was proved...

Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA) and demonstrate its proof-of-principle applications in high-sensitivity and high-th...

We report the design, fabrication, and characterization of planar arrays of externally-fed silicon electrospinning emitters for high-throughput generation of polymer nanofibers. Arrays with as many as 225 emitters and with emitter density as large as 100 emitters cm(-2) were characterized using a solution of dissolved PEO in water and ethanol. Devices with emitter density as high as 25 emitters...

Room-temperature quantum emitters in gallium nitride (GaN) are reported. The emitters originate from cubic inclusions in hexagonal lattice and exhibit narrowband luminescence in the red spectral range. The sources are found in different GaN substrates, and therefore are promising for scalable quantum technologies.

Cationic iridium(III) complexes represent the single largest class of emitters used in light emitting electrochemical cells (LEECs). In this chapter, we highlight the state-of-the-art emitters in terms of efficiency and stability in LEEC devices, highlighting blue, green, yellow/orange, red and white devices, and provide an outlook to the future of LEECs.