Edinburgh Lecture in Photophysics and Photochemistry: Molecular Light Management for Energy Conversion

Presenter: Prof. Dirk Guldi, Distinguished Professor of Chemistry, Chair of Physical Chemistry, Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg

We present recent work from our laboratory focused on molecular strategies for photon downconversion and upconversion aimed at surpassing the detailed balance limit of solar cell efficiency.  For high-energy photons with energies above the semiconductor bandgap, I will show how singlet fission (SF) – a downconversion mechanism – helps mitigate thermalization losses.  In this process, a single high-energy photon absorbed by a molecule generates two lower-energy triplet excitons, effectively doubling the number of charge carriers. 

For low-energy photons below the semiconductor bandgap, triplet-triplet annihilation upconversion (TTA-UC) offers a complementary approach by enabling photon upconversion to reduce sub-bandgap losses.  TTA-UC works by combining the energy of two triplet-excited molecules to populate a higher-energy singlet state, which can then fluoresce and emit a single photon of higher energy -essentially the reverse of singlet fission. 

Together, these strategies demonstrate how acene-based materials can address key loss mechanisms in conventional solar cells by managing both high- and low-energy photon losses.

Please join for a reception following the lecture.