Change in Tetracene Polymorphism Facilitates Triplet Transfer in Singlet Fission-Sensitized Silicon Solar Cells

TL;DR

This study demonstrates that changing tetracene's polymorphism through air exposure enhances triplet exciton transfer into silicon, potentially increasing solar cell efficiency by utilizing singlet fission.

Contribution

It reveals that air-induced polymorphic change in tetracene improves triplet transfer into silicon, a novel approach to enhance singlet fission-based solar cells.

Findings

Triplet transfer yield into Si is approximately 50%.

Triplet transfer time is measured at 215 ns.

Polymorphic control during tetracene deposition is crucial for efficiency.

Abstract

Singlet fission in tetracene generates two triplet excitons per absorbed photon. If these triplet excitons can be effectively transferred into silicon (Si) then additional photocurrent can be generated from photons above the bandgap of Si. This could alleviate the thermalization loss and increase the efficiency of conventional Si solar cells. Here we show that a change in the polymorphism of tetracene deposited on Si due to air exposure, facilitates triplet transfer from tetracene into Si. Magnetic field-dependent photocurrent measurements confirm that triplet excitons contribute to the photocurrent. The decay of tetracene delayed photoluminescence was used to determine a triplet transfer time of 215 ns and a maximum yield of triplet transfer into Si of ~50 %. Our study suggests that control over the morphology of tetracene during deposition will be of great importance to boost the triplet transfer yield further.