EP02.09.04 : Energy Transfer from Tetracen via PbS Quantum Dots into Silcon

5:00 PM–7:00 PM Apr 4, 2018

PCC North, 300 Level, Exhibit Hall C-E

Stefan Tabernig1 Benjamin Daiber1 Tianyi Wang1 Bruno Ehrler1

1, AMOLF, Amsterdam, , Netherlands

Singlet Fission sensitized solar cells are a possible solution to overcome the Shockley Queisser efficiency limit for single junction solar cells. Combining singlet fission materials with silicon is promising since silicon is the dominating material for solar cells on the market.
In one implementation, a singlet fission layer made from tetracene absorbs high-energy photons (> 2.5 eV) whose energy is split into two triplet excitons with half the energy (1.25eV) via singlet fission. Combining the tetracene sensitizer material with silicon (bandgap ~1.1eV) can increase the theoretical maximum solar cell efficiency to around 44%
However, transferring triplet excitons from tetracene into silicon stays elusive. It has been shown that it is possible to transfer triplet excitons from tetracene to PbS quantum dots. Once in the quantum dot, the energy can be transferred by Förster resonant energy transfer (FRET). Here we calculate the FRET efficiency from PbS quantum dots into silicon, using realistic material parameters. We study the influence of the device geometry, donor-acceptor distance, and quantum dot bandgap on the energy transfer efficiency. We find that a short spacing of < 1 nm between the quantum dots and silicon is necessary to obtain a transfer efficiency of >80%. The small absorption coefficient of silicon leads to poor efficiencies for larger distances. Our work lays the foundation to enable singlet fission solar cells with an intermediate QD layer that facilitates energy transfer.