A Silicon-Singlet Fission Parallel Tandem Solar Cell Exceeding 100 % External Quantum Efficiency

TL;DR

This paper introduces a novel silicon-singlet fission parallel tandem solar cell that surpasses 100% external quantum efficiency, potentially exceeding traditional efficiency limits and offering improved stability for solar energy conversion.

Contribution

It presents a new parallel tandem solar cell design based on singlet fission, achieving efficiency beyond 100% QE and demonstrating practical viability.

Findings

Exceeds 100% external quantum efficiency at key absorption peak.

Demonstrates efficient photocurrent addition in parallel tandem configuration.

Shows potential for surpassing traditional silicon solar cell efficiency limits.

Abstract

Silicon solar cells dominate the solar cell market with record lab efficiencies reaching almost 26%. However, after 60 years of research, this efficiency saturated close to the theoretical limit for silicon, and radically new approaches are needed to further improve the efficiency. Here we present parallel-connected tandem solar cells based on down-conversion via singlet fission. This design allows raising the theoretical power conversion efficiency limit to 45% with far superior stability under changing sunlight conditions in comparison to traditional series tandems. We experimentally demonstrate a silicon/pentacene parallel tandem solar cell that exceeds 100% external quantum efficiency at the main absorption peak of pentacene, showing efficient photocurrent addition and proving this design as a realistic prospect for real-world applications.