University of Michigan

Dejiu Fan

Stephen R Forrest

Kyusang Lee

Jeramy David Zimmerman

Andrej Lenert

Caleb Coburn

Byungjun Lee

Tobias Eugene Burger

Xinjing Huang

A method of fabricating an organic optoelectronic device comprises positioning a patterning layer over a substrate, etching the patterning layer using a photolithographic process to create an etched patterning layer, positioning a layer of an organic material over the etched patterning layer, and removing at least a portion of the etched patterning layer and at least a portion of the layer of the organic material to create a patterned organic layer over the substrate.

Peel-off patterning method for fabrication of organic optoelectronic devices

To reach high efficiencies, thermophotovoltaic cells must utilize the broad spectrum of a radiative thermal source. One promising approach to overcome this challenge is to have low-energy photons reflected and reabsorbed by the thermal emitter, where their energy can have another chance at contributing toward photogeneration in the cell. However, current methods for photon recuperation are limited by insufficient bandwidth or parasitic absorption, resulting in large efficiency losses relative to theoretical limits. This work demonstrates nearly perfect reflection of low-energy photons (˜99%) by embedding an air layer within the TPV cell. This result represents a four-fold reduction in parasitic absorption relative to existing TPV cells. As out-of-band reflectance approaches unity, TPV efficiency becomes nearly insensitive to cell bandgap and emitter temperature. Accessing this regime unlocks a range of possible materials and heat sources that were previously inaccessible to TPV energy conversion.

Thermophotovoltaic cells with integrated air-bridge for improved efficiency

An organic optoelectronic device comprises a substrate having first and second regions, a first electrode positioned over the first region of the substrate, a shutter electrode positioned over the second region of the substrate, an organic heterojunction layer comprising an organic heterojunction material, positioned over at least a portion of the first electrode, an insulator layer positioned over at least a portion of the shutter electrode, an organic channel layer, comprising an organic channel material, positioned over at least a portion of the heterojunction and insulator layers, and a second electrode positioned over the channel layer in the second region of the substrate, wherein the shutter electrode is configured to generate a repulsive potential barrier in the channel layer, suitable to at least reduce movement of charge in the channel layer. A method of measuring received light in an optoelectronic device is also described.

Organic optoelectronic device

The present disclosure relates to methods and growth structures for making thin-film electronic and optoelectronic devices, such as flexible photovoltaic devices, using epitaxial lift-off (ELO). In particular, disclosed herein are wafer protection schemes that preserve the integrity of the wafer surface during ELO and increase the number of times that the wafer may be used for regrowth. The wafer protection schemes use growth structures that include at least one superlattice layer.

Non-destructive wafer recycling for epitaxial lift-off thin-film device using a superlattice epitaxial layer

Disclosed herein are methods to eliminate or reduce the peeling-off of epitaxial lifted-off thin film epilayers on secondary host substrates that allow for the fabrication of high yield ELO processed thin film devices. The methods employ patterned strain-relief trenches.

Strain relief epitaxial lift-off via pre-patterned mesas

There is disclosed a method of preparing a photovoltaic device. In particular, the method comprises integrating epitaxial lift-off solar cells with mini-parabolic concentrator arrays via a printing method. Thus, there is disclosed a method comprising providing a growth substrate; depositing at least one protection layer on the growth substrate; depositing at least one sacrificial layer on the protection layer; depositing at least one photoactive cell on the sacrificial layer; etching a pattern of at least two parallel trenches that extend from the at least one photoactive cell to the sacrificial layer; depositing a metal on the at least one photoactive cell; bonding said metal to a host substrate; and removing the sacrificial layer with one or more etch steps. The host substrate can be a siloxane, which when rolled, can form a stamp used to integrate solar cells into concentrator arrays. There are also disclosed a method of making a growth substrate and the growth substrate made therefrom.

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Ann Arbor, MI, United States of America

Dejiu Fan