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An external dielectric coating is shown to enhance energy conversion in an organic photovoltaic cell with metal anode and cathode by increasing the optical field intensity in the organic layers. Improved light incoupling in the device is modeled using transfer matrix simulations and is confirmed by in situ measurement of the photocurrent during growth of the coating. The optical field intensity in optimized cell geometries is predicted to exceed that in analogous devices using indium tin oxide, both cell types having equivalent anode sheet resistance, suggesting a broader range of compatible substrates (e.g., metal foils) and device processing techniques.

Organic light-emitting devices ͑OLEDs͒ were fabricated on scanning probe cantilevers using a combination of thermally evaporated molecular organic compounds and metallic electrodes. Ion beam milling was used to define the emissive region in the shape of a ring having a diameter of less than 5 m and a narrow width. Stable light emission was observed from the device at forward bias, with a current-voltage response similar to that of archetypal OLEDs. Based on this device, a novel electrically pumped scanning optical microscopy tool is suggested.

An organic light-emitting device was fabricated on a commercial atomic force microscopy (AFM) probe having a pyramidal tip by a lithography-free vacuum thermal evaporation (VTE) process. The line-of-sight molecular transport characteristic of VTE results in controlled thickness variation across the nonplanar substrate, such that localized current injection occurs at the tip region. Furthermore, the high curvature of the AFM tip vertex concentrates the electric field, causing highly localized bipolar charge injection, accompanied by photon emission from a region less than a micrometer across. This light source exhibits a range of features potentially attractive for applications such as probe-based optical microscopy, nanoscale light sensing, and chemical detection.

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