Light-harvesting discotic liquid crystalline porphyrins and metal complexes

Abstract

Novel discotic liquid crystalline porphyrins and discotic liquid crystalline metal complexes, methods for their preparation, and device fabrication are disclosed. Materials with partially perfluorinated alkyl group in the peripheral chains show a strong tendency towards the formation of homeotropic alignment. These compounds are capable of being used as high-efficiency photovoltaic materials, organic semiconducting materials, and organic light emitting materials.

Description

[0001]The present application claims priority to U.S. Provisional Patent Application Ser. No. 60 / 790,996, filed Apr. 11, 2006, and is a continuation in part and claims priority from prior U.S. patent application Ser. No. 11 / 325,478, filed Jan. 4, 2006.BACKGROUND[0002]The present exemplary embodiments relate to discotic liquid crystalline porphyrins and discotic liquid crystalline porphyrin metal complexes. In certain embodiments, their homeotropically or homogeniously aligned architecture, in which the columns formed by intermolecular stack are spontaneously perpendicular or parallel on the surface respectively, is a crucial point for their applications. They find use as high-efficiency photovoltaic materials, organic semiconducting materials, organic light emitting materials, materials for organic transistors and in solar cell device implementation. However, it is to be appreciated that the present exemplary embodiments are also amenable to other like applications.[0003]In the long...

AI Technical Summary

Problems solved by technology

A grand challenge is to convert solar energy into green electric energy in an inexpensive and efficient way.

Crystalline silicon photovoltaic cells, though efficient, are too expensive to compete with primary fossil energy.

New OPV materials able to efficiently absorb sunlight and new approaches based on nanostructured architectures holds the potential to revolutionize the technology used to produce solar electricity; however the availability of such new materials with tailored properties has undoubtedly posed a bottleneck to the OPV technology.

Currently widely used OPV materials, e.g. polycrystalline Cu phthalocyanine, suffer from the scattering of electron / exciton between small crystal grain boundaries in which random arrangement of molecules results in poor charge mobility.

The existing grain boundaries and defects act as deep traps that dramatically reduce the charge mobility.

The attainment of large defect-free single crystals or single crystalline film of large area of either inorganic (e.g. silicon) or organic molecules is difficult and costly.

A challenge for OPV, with the possibility of very significant cost reduction, is to make them in desired macroscopic order to improve charge transportation etc.

Unfortunately, the preferable homeotropic-alignment of discotic LCs, especially those having large conjugated systems, is difficult to achieve due to their high viscosity and poor affinity to substrates, as compared to the well established technologies for their calamitic counterparts in the display industry.

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