Low temperature interconnection of nanoparticles

Abstract

A polymeric linking agent enables the manufacture of photovoltaic cells on flexible substrates, including, for example, polymeric substrates. Photovoltaic cells may be fabricated by a relatively simple continuous manufacturing process, for example, a roll-to-roll process, instead of a batch process.

Description

FIELD OF THE INVENTION The invention relates generally to the field of photovoltaic devices, and more specifically to chemical structures and methods of interconnecting nanoparticles at low temperatures. BACKGROUND OF THE INVENTION Thin film solar cells composed of percolating networks of liquid electrolyte and dye-coated sintered titanium dioxide were developed by Dr. Michael Grätzel and coworkers at the Swiss Federal Institute of Technology. These photovoltaic devices fall within a general class of cells referred to as dye-sensitized solar cells (“DSSCs”). Conventionally, fabrication of DSSCs requires a high temperature sintering process (>about 400° C.) to achieve sufficient interconnectivity between the nanoparticles and enhanced adhesion between the nanoparticles and a transparent substrate. Although the photovoltaic cells of Grätzel are fabricated from relatively inexpensive raw materials, the high temperature sintering technique used to make these cells limits the cell s...

AI Technical Summary

Benefits of technology

The invention in, one embodiment, addresses the deficiencies of the prior art by providing a polymeric linking agent that enables the fabrication of thin film solar cells at relatively low temperatures. This enables the manufacture of such cells on flexible substrates, including, for example, those substrates constructed from somewhat heat sensitive polymeric materials. In addition, the invention provides photovoltaic cells and methods of photovoltaic cell fabrication that facilitate their manufacture by a relatively simple, continuous manufacturing process. For example, a roll-to-roll process can be utilized instead of the batch processes that limited the prior art. More particularly, in one embodiment, the invention provides a method for interconnecting metal oxide nanoparticles in DSSCs, with reduced or no heating, using a polymeric linking agent. By way of example, metal oxide nanoparticles may be interconnected by contacting the nanoparticles with a suitable polymeric linking agent dispersed in a solvent, such as n-butanol, at about room temperature or at elevated temperatures below about 300° C.

In one embodiment of the photovoltaic cell, at least one of the first and second flexible, significantly light transmitting substrates includes a transparent substrate (e.g., a polyethylene terephthalate material). In another embodiment, the photovoltaic cell includes a catalytic media layer disposed between the first and second flexible, significantly light transmitting substrates. The catalytic media layer is, for example, platinum. In another embodiment, the photovoltaic cell includes an electrical conductor material disposed on at least one of the first and second flexible, significantly light transmitting substrates. In another embodiment, the electrical conductor material is, for example, indium tin oxide.

In one embodiment of the photovoltaic cell, at least one of the first and second flexible, significantly light transmitting substrates includes a transparent substrate (e.g., a polyethylene terephthalate material). In another embodiment, the photovoltaic cell includes a catalytic media layer disposed between the first and second flexible, significantly light transmitting substrates. The catalytic media layer is, for example, platinum. In another embodiment, the photovoltaic cell includes an electrical conductor material disposed on at least one of the first and second flexible, significantly light transmitting substrates. In another embodiment, the electrical conductor material is, for example, indium tin oxide.

Problems solved by technology

Although the photovoltaic cells of Grätzel are fabricated from relatively inexpensive raw materials, the high temperature sintering technique used to make these cells limits the cell substrate to rigid transparent materials, such as glass, and consequently limits the manufacturing to batch processes and the applications to those tolerant of the rigid structure.

Furthermore, the high temperature sintering process increases the cost of manufacturing a photovoltaic cell due to the energy required to perform the sintering.

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