Diketopyrrolopyrrole Derivatives Functionalized with N-Annulated PDI and Se-Annulated PDI by Direct (Hetero)Arylation Methods

27 February 2020, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

We report on the synthesis of diketopyrrolopyrrole (DPP) derivatives functionalized with N-annulated and Se-annulated perylene diimide (NPDI and SePDI, respectively) via direct (hetero)arylation methods. DPP is symmetrically bifunctionalized with SePDI (SePDI–DPP–SePDI) and unsymmetrically functionalized with SePDI and NPDI (SePDI–DPP–NPDI). The effects of Se substitution compared to N substitution on physical, electrochemical, and optical properties are investigated along with performance as non-fullerene acceptors in photovoltaic devices. It is found that Se substitution increases the electron affinity of the p-conjugated molecule and blue shifts the optical absorption spectra, observations that were supported by computational analysis. Steric strain between the PDI endcap and DPP core prevent complete electronic communication along the p-conjugated backbone and results in the unsymmetrical compound, SePDI‒DPP‒NPDI, having electronic and optical properties that are a linear combination of both the symmetrical SePDI and NPDI based compounds. Different is that the SePDI‒DPP‒NPDI compound has a distinct melt observed at 343 °C and organic photovoltaic devices based on this compound had lower than expected open-circuit voltages, suggesting a unique solid-state packing arrangement. SePDI-based compounds performed worse than the NPDI-based compound in organic photovoltaic devices using the donor polymer PTB7-Th.

Keywords

Diketopyrrolopyrrole
Perylene Diimide
Organic Photovoltaics
Solvent Vapor Annealing
Direct (Hetero) Arylation

Comments

Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.