Organic/Organic' heterojunctions: organic light emitting diodes and organic photovoltaic devices.

Heterojunctions created from thin films of two dissimilar organic semiconductor materials [organic/organic' (O/O') heterojunctions] are an essential component of organic light emitting diode displays and lighting systems (OLEDs, PLEDs) and small molecule or polymer-based organic photovoltaic (solar cell) technologies (OPVs). O/O' heterojunctions are the site for exciton formation in OLEDs, and the site for exciton dissociation and photocurrent production in OPVs. Frontier orbital energy offsets in O/O' heterojunctions establish the excess free energy controlling rates of charge recombination and formation of emissive states in OLEDs and PLEDs.

Dynamic surface tension and adhesion detection for the rapid analysis of surfactants in flowing aqueous liquids.

A multidimensional dynamic surface tension detector (DSTD) for flowing liquid samples is reported. The DSTD is based on measuring the pressure with time of a repeating drop formed by the flow of liquid out the end of a pointed stainless steel capillary. This pressure-based DSTD provides information on dynamic surface tension at the air-liquid interface and adhesion at the solid-liquid interface on the side of the pointed capillary tip for each drop of surfactant solution, resulting in rapid characterization of complex samples.