Thursday, August 21, 2008

US Patent 7414294 - Intermediate band core/shell quantum dots provided in organic matrix

This patent discloses a quantum dot based composites useful for solar cells in which band matching is achieved between quantum dots and an organic matrix. Claim 1 reads:

1. A photosensitive device comprising:

a plurality of quantum dots, each quantum dot having a shell; and

an organic matrix, the quantum dots being embedded in the organic matrix, at least the quantum dots and the organic matrix being photoconductive semiconductors, the shell around each quantum dot being arranged as a tunneling barrier to require an electron in a lowest unoccupied molecular orbital (LUMO) of the organic matrix to perform quantum mechanical tunneling to reach the respective quantum dot, and a first quantum state above the band gap in each quantum dot being between the LUMO and a highest occupied molecular orbital (HOMO) of the organic matrix, wave functions of the first quantum state of the plurality of quantum dots to overlap as an intermediate band.