Here we present recent progress in developing efficient wet-coated organic light-emitting
devices (OLEDs) for lighting applications. In particular, we describe a novel approach
for building efficient wet-coated dye-doped blue phosphorescent devices. Further, a novel
approach for achieving arbitrary emission patterning for OLEDs is discussed. This approach
utilizes a photo-induced chemical doping strategy for selectively activating charge injection
materials, thus enabling devices with arbitrary emission patterning. This approach may provide
a simple, low cost path towards specialty lighting and signage applications for OLED
Organic light-emitting devices (OLEDs) have shown great promise for general lighting applications. Over the past several years, tremendous progress has been made in improving performance attributes such as light quality, efficacy and lifetime of OLEDs. However, achieving the low cost manufacturing potential of OLEDs, another stringent requirement to enable lighting applications, has so far not been well addressed and explored. Here, we describe a vacuum-free, direct lamination process that could reduce OLED manufacturing costs substantially below what is currently possible. With this technique, OLEDs can be made by laminating an anode component to a separately engineered cathode component using a roll laminator. When coupled with a solution-based chemical n-doping strategy to enable efficient electron injection from an inert cathode into polymeric organic semiconductors, the lamination technique is able to produce high performance OLEDs with efficiency comparable to conventionally fabricated devices utilizing a vacuum-deposited, reactive metal cathode.
Photovoltaic cells require deposition of a platinum layer at the cathode to serve as a catalyst for reduction of redox carriers in PV cells. Current dye-sensitized solar cells (DSSC) employ high temperature decomposition of chloroplatinic acid to give platinum islands. In order to produce DSSCs with plastic substrates, a low temperature platinum deposition process was developed. Initial experiments showed that platinum was deposited if Karstedt platinum catalyst solution in hexamethyldisilazane (HMDZ) was coated onto a substrate followed by heating under 150°C. PV cell performance of Karstedt-HMDZ-containing platinum was inferior to cells made with high temperature platinum. However, CODPtMe2 (COD = 1,5-cyclooctadiene) was found to be a platinum precursor that led to PV cell performance equivalent to that obtained from high temperature platinum. Other precursors were evaluated as well including MeCpPtMe3 that permitted platinum deposition via UV irradiation. Kelvin Probe analysis was also performed on several platinum films prepared from a variety of precursors on several substrates under a variety of conditions. CPD values of
< -0.6eV appeared to predict good PV cell performance. Further application of the low temperature-derived platinum films was made for organic light emitting diodes.