Publication Date

2017-05-01

Availability

Open access

Embargo Period

2017-05-01

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Chemistry (Arts and Sciences)

Date of Defense

2017-03-29

First Committee Member

Françisco M. Raymo

Second Committee Member

Jamie D. Walls

Third Committee Member

Burjor Captain

Fourth Committee Member

Joshua Cohn

Abstract

With an impending surge in the global demand for energy, there is a need for disruptive solar energy harvesting approaches. Supramolecular donor-acceptor polymers that undergo long-distance, photo-induced charge separation, are one solution to this challenge. We report that supramolecular polymer films composed of a 2:1 mixture of mono-diamidopyridine diketopyrrolopyrrole (DPP) electron donors and perylene derived bisdiimide (PDI) electron acceptors, undergo photo-induced charge transfer in the solid-state. The two monomers form 2:1 helical heteroaggregate supramolecular polymers as a result of triple H-bonding and π •••π stacking orthogonal to the H-bonding axis. Using ultrafast transient absorption spectroscopy, we demonstrate that recombination lifetimes increase a thousand-fold compared to solution. Supramolecular donor-acceptor polymer films were designed by considering structure and electron transfer dynamics synergistically. This route towards functional hierarchical superstructures could lead to new materials for artificial photosynthesis and organic electronics.

Keywords

photo-induced charge separation; Supramolecular donor-acceptor polymers; ultrafast transient absorption spectroscopy

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