Optoelectronic Components & Materials Group

(above) A hemispherical array photodetector is pictured above. The curved detector surface allows this device to produce an undistorted, wide field image using only a single lens. Because it shares this attribute with the human eye, a hemispherical photodetector is informally called an artifical eye.

Conventional photodector arrays are printed on flat substrates, and must be combined with multiple lenses to produce high quality images. Organic photodetectors can be grown on curved substrates, enabling fabrication of an artifical eye.

You can read about this and other projects on our research page.

Optoelectronic Components & Materials Group

(Top) Cutaway of a dielectric low-index grid (LIG) embedded within the organic layer of an OLED to redirect light towards the forward viewing direction. By reducing the amount of light lost within the device structure and increasing the amount of light the the OLED emits into its environment, a LIG makes OLEDs more efficient.

(Bottom) Full electromagnetic wave simulations of Light outcoupling in OLEDs by a single grid cell for different grid geometries. High field regions appear in red.

A LIG can incrase light extraction from waveguided modes by nearly 50%. When this technique is coupled with additional methods to extract light, a nearly threefold enhancement in efficiency is achievable. You can read about this and other projects on our research page.

Optoelectronic Components & Materials Group

Differential interference contrast microscopy uses color to enhance small differences in the surface topography and crystal orientation of a crystallized squaraine film after high temperature annealing. This photograph was taken by Physics graduate student Kevin Bergemann. Squaraines are a group of materials which show great promise for use in efficient organic photovoltaic cells. This image won first place in the category of optical and scanning electron microscopy in University of Michgian's 2011 Imaging Microstructure Contest. You can read about this and other projects on our research page.

Optoelectronic Components & Materials Group

This image shows a differential interference contrast micrograph of a single crystal of copper phthalocyanine grown over a substrate of potassium bromide. Copper phthalocyanine is a commonly used pigment and organic semiconductor. When grown under specific conditions, it can form large crystals with interesting optical and electronic properties. This image was taken by Materials Science and Engineering graduate student Brian Lassiter. It won second place in the category of optical and scanning electron microscopy in University of Michgian's 2011 Imaging Microstructure Contest. You can read about this and other projects on our research page.