Singlet Fission Photovoltaics: Progress and Promising Pathways

TL;DR

This paper reviews the progress in singlet fission photovoltaics, highlighting its potential to significantly improve solar cell efficiency by generating multiple excitons and reducing energy losses.

Contribution

It categorizes and assesses various approaches to integrating singlet fission into photovoltaic devices, identifying promising future research directions.

Findings

Singlet fission can produce nearly double the excitons per photon.

Various device structures have been explored for singlet fission integration.

The process offers a pathway to surpass traditional solar cell efficiency limits.

Abstract

Singlet fission is a form of multiple exciton generation which occurs in organic chromophores when a high energy singlet exciton separates into two lower energy triplet excitons, each with approximately half the singlet energy. Since this process is spin-allowed it can proceed on an ultrafast timescale of less than several picoseconds, outcompeting most other loss mechanisms and reaching quantitative yields approaching 200%. Due to this high quantum efficiency, the singlet fission process shows promise as a means of reducing thermalisation losses in photovoltaic cells. This would potentially allow for efficiency improvements beyond the thermodynamic limit in a single junction cell. Efforts to incorporate this process into solar photovoltaic cells have spanned a wide range of device structures over the past decade. In this review we compare and categorise these attempts in order to assess the state of the field and identify the most promising avenues of future research and development.