We demonstrate that attenuated luminescence and lasing in optically excited organic thin films is a sensitive probe to vapours of explosives, such as trinitrotoluene (TNT). The combined chemosensing gains from organic amplifying materials and the lasing action, promise to deliver sensors that can detect explosives with unparalleled sensitivity.
Creation of patterned, efficient, and saturated color hybrid organic/inorganic quantum dot light emitting devices (QD-LEDs) is dependent on development of integrated fabrication and patterning methods for the QD layer. We show that micro-contact printing can be applied to QD deposition, generating micron-scale pattern definition, needed in pixilated-display applications. We demonstrate saturated color QD-LEDs with external quantum efficiencies in excess of 1%. Combining this technique with the use of wide optical band gap host materials, and a new synthetic route for the creation of blue emitting (CdS)ZnS nanocrystals, it is now possible to fabricate QD-LEDs with saturated color emission in the red, green and blue regions of the spectrum.
We review recent results form two types of small molecule organic light emitting devices (OLEDs). For flat panel display applications, we have developed a novel OLED pixel in which the R, G and B emission layers are vertically stacked to provide a simple fabrication process, minimum pixel size, and maximum fill factor. In separate experiments, we have worked towards achieving electrically- pumped organic lasers by demonstrating low-threshold lasing in an optically-pumped thin film double heterostructure consisting entirely of organic semiconducting materials.
We review recent progress in small molecule organic light emitting devices (OLEDs) with emphasis on their potential application to lightweight, head-up displays. We discuss OLEDs grown on thin, flexible, plastic substrates which may be bent over a radius of curvature of as little as 0.7 cm without damage and exhibit operating voltages and efficiencies similar to OLEDs grown on conventional glass substrates. Transparent OLEDs grown on such substrates create the potential for a new type of lightweight, full- color, OLED pixel in which the R, G and B emission layers are vertically stacked to provide a simple fabrication process, minimum pixel size, and maximum fill factor.
Image states on the surface of bare and adsorbate covered metals form simple, near-surface, bound electron systems. These systems provide useful model systems for understanding the electron- transfer dynamics between an adsorbate molecule and its underlying substrate. These states may be readily detected by two-photon photoemission, a technique ideally suited for high- resolution studies of excited surface states. Because of its relatively narrow linewidths, spectroscopy of the image states provides a useful method of detecting changes in surface and composition.