Is energy transfer limiting multiphotochromism? answers from ab initio quantifications

Area of Science:

• Supramolecular chemistry
• Organic electronics
• Photochemistry

Background:

• Dithienylethenes (DTEs) are key components in multiphotochromic systems for optoelectronics.
• Partial photoactivity in DTE dimers is a known issue, hindering device functionality.
• Excited state energy transfer (EET) is hypothesized but not experimentally proven to cause this limitation.

Purpose of the Study:

• To computationally rationalize the phenomenon of excited state energy transfer (EET) in DTE dimers.
• To investigate the mechanisms (through-bond and through-space) influencing EET.
• To provide a theoretical basis for designing efficient DTE-based multiswitches.

Main Methods:

• Time-Dependent Density Functional Theory (TD-DFT) was employed.
• Calculation of electronic coupling in DTE dimers.
• Analysis of through-bond and through-space contributions to EET.

Main Results:

• The study provides the first computational rationalization of parasitic EET in DTE dimers.
• Quantification of EET in various DTE systems.
• Detailed analysis of the influence of linker nature and length on EET.

Conclusions:

• Computational data align with experimental observations of partial photoactivity in DTEs.
• Understanding EET mechanisms is crucial for designing functional DTE multiswitches.
• This work enables rational molecular design for improved optoelectronic devices.