/pdf/self-assembled-monolayers-of-thiolates-on-metals-as-a-form-1neb0hj3k4.pdf

Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

The development of white organic light-emitting diodes (OLEDs) holds great promise for the production of highly efficient large-area light sources. High internal quantum efficiencies for the conversion of electrical energy to light have been realized. Nevertheless, the overall device power efficiencies are still considerably below the 60-70 lumens per watt of fluorescent tubes, which is the current benchmark for novel light sources. Although some reports about highly power-efficient white OLEDs exist, details about structure and the measurement conditions of these structures have not been fully disclosed: the highest power efficiency reported in the scientific literature is 44 lm W(-1) (ref. 7). Here we report an improved OLED structure which reaches fluorescent tube efficiency. By combining a carefully chosen emitter layer with high-refractive-index substrates, and using a periodic outcoupling structure, we achieve a device power efficiency of 90 lm W(-1) at 1,000 candelas per square metre. This efficiency has the potential to be raised to 124 lm W(-1) if the light outcoupling can be further improved. Besides approaching internal quantum efficiency values of one, we have also focused on reducing energetic and ohmic losses that occur during electron-photon conversion. We anticipate that our results will be a starting point for further research, leading to white OLEDs having efficiencies beyond 100 lm W(-1). This could make white-light OLEDs, with their soft area light and high colour-rendering qualities, the light sources of choice for the future.

White organic light-emitting diodes with fluorescent tube efficiency

The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of a nanostructured surface or nanoparticle lies at the heart of SERS, the ability to reliably control the surface characteristics has taken SERS from an interesting surface phenomenon to a rapidly developing analytical tool. This article first explains many fundamental features of SERS and then describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates. In particular, we review metal film over nanosphere surfaces as excellent candidates for several experiments that were once impossible with more primitive SERS substrates (e.g., metal island films). The article also describes progress in applying SERS to the detection of chemical warfare agents and several biological molecules.

Surface-Enhanced Raman Spectroscopy

Recent startling interest for lanthanide luminescence is stimulated by the continuously expanding need for luminescent materials meeting the stringent requirements of telecommunication, lighting, electroluminescent devices, (bio-)analytical sensors and bio-imaging set-ups. This critical review describes the latest developments in (i) the sensitization of near-infrared luminescence, (ii) “soft” luminescent materials (liquid crystals, ionic liquids, ionogels), (iii) electroluminescent materials for organic light emitting diodes, with emphasis on white light generation, and (iv) applications in luminescent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation (500 references).

/pdf/lanthanide-luminescence-for-functional-materials-and-bio-1w9cppwf8r.pdf

Lanthanide luminescence for functional materials and bio-sciences

Surface-enhanced Raman spectroscopy.

We report the synthesis and electroluminescent properties of the organometallic complex diphenyltin bis-hydroxyquinoline (Sph2q2). The complex was prepared by the reaction of diphenyltin dichloride with 8-hydroxyquinoline and shows an absorption cutoff wavelength of 460 nm and bright photoluminescence with a peak wavelength at 508 nm. The ionization potential of Sph2q2 was determined to be ∼6.0 eV by photoemission apparatus, and the electron affinity is estimated to be 3.3 eV. Sph2q2 was used as an emitting and electron injection layer in bilayer devices. The electroluminescence (EL) properties and charge injection properties of Sph2q2 are characterized. Sph2q2 is easily soluble in common organic solvents and further modification of its properties is possible. The results indicate that tetravalent tin complexes are potential emitting and charge injection materials for EL applications.

Tetravalent tin complex with high electron affinity for electroluminescent applications

Photovoltaics of photoactive protein/polypeptide LB films

Imaging two-dimensional arrays of soluble proteins by atomic force microscopy in contact mode using a sharp supertip

The anchoring structures of smectic liquid crystals, n-alkylcyanobiphenyl (mCB: m=8, 10, 12), on molybdenum disulfide (MoS2) are directly observed by scanning tunneling microscopy (STM) in order to analyze the alignment mechanism of liquid crystals. For 8CB, the anchoring structure is of the periodic monolayer type, while 10CB and 12CB take a bilayer structure in which there is no interdigitation of the cyano groups. These structures on MoS2 depend on the length of the alkyl group in contrast to those on graphite. The mechanism of alignment is discussed based on the STM results.

https://iopscience.iop.org/article/10.1143/JJAP.29.L2243/pdf

Hiroyuki Sasabe

Papers

Tetravalent tin complex with high electron affinity for electroluminescent applications

Photovoltaics of photoactive protein/polypeptide LB films

Imaging two-dimensional arrays of soluble proteins by atomic force microscopy in contact mode using a sharp supertip

Two types of anchoring structure in smectic liquid crystal molecules

A new synthetic approach for polymers containing a high density of second-order nonlinear optical chromophores