US 7,125,578 B1 · Photoinduced charge-transfer materials for nonlinear optical applications

Abstract

A method using polyelectrolyte self-assembly for preparing multi-layered organic molecular materials having individual layers which exhibit ultrafast electron and/or energy transfer in a controlled direction occurring over the entire structure. Using a high molecular weight, water-soluble, anionic form of poly-phenylene vinylene, self-assembled films can be formed which show high photoluminescence quantum efficiency (QE). The highest emission QE is achieved using poly(propylene-imine) (PPI) dendrimers as cationic binders. Self-quenching of the luminescence is observed as the solid polymer film thickness is increased and can be reversed by inserting additional spacer layers of transparent polyelectrolytes between each active conjugated layer, such that the QE grows with thickness. A red shift of the luminescence is also observed as additional PPV layers are added. This effect persists as self-quenching is eliminated. Charge transfer superlattices can be formed by additionally incorporating C60 acceptor layers.

Claims24

Dependent claims

A method for generating materials which exhibit photoinduced charge transfer having a controlled direction, which comprises the steps of:

(a) depositing a donor layer directly onto a substrate, the substrate consisting of non-conductive glass, wherein the donor layer comprises at least one of an electron donor and an energy donor;
(b) depositing a nonlinear optical chromophore material directly onto the donor layer;
(c) depositing an acceptor layer directly onto the nonlinear optical chromophore material, wherein the acceptor layer comprises at least one of an electron acceptor and an energy acceptor;
and
(d) self-assembling the donor layer, the nonlinear optical chromophore material layer, and the acceptor layer into a superlattice, whereby photoinduced charge transfer is achieved between the donor layer and the acceptor layer, thereby enhancing the nonlinear optical properties of the nonlinear optical chromophore material.

2 more elements

A method for generating materials which exhibit energy transfer having a controlled direction, which comprises the steps of:

(a) depositing a donor layer directly onto a substrate, the substrate consisting of non-conductive glass, wherein the donor layer comprises at least one of an electron donor and an energy donor;
(b) depositing a transparent spacer layer comprising at least one substantially inert polyelectrolyte directly onto the donor layer;
and
(c) depositing an acceptor layer onto the transparent spacer layer, wherein the acceptor layer comprises at least one of an electron acceptor and an energy acceptor, and wherein the donor layer and acceptor layer are selected from the group consisting of conjugated polymers, fullerenes, porphyrins, and phthalocyanines, wherein the fullerenes include functionalized derivatives of C60 having ionic groups such that the fullerenes are rendered water-soluble;
and
(d) self-assembling the donor layer, the transparent spacer layer, and the acceptor layer into a superlattice, whereby energy transfer is achieved between the donor layer and the acceptor layer.

3 more elements

Dependencies are inferred from the claim text.

Photoinduced charge-transfer materials for nonlinear optical applications

Life of this patent

Photoinduced charge-transfer materials for nonlinear optical applications

Life of this patent

Abstract

Claims24