Exciton Lifetime Paradoxically Enhanced by Dissipation and Decoherence - Toward Efficient Energy Conversion of Solar Cell

TL;DR

This paper demonstrates that, contrary to conventional wisdom, dissipation and decoherence can enhance exciton lifetime in photovoltaic materials by inducing a quantum-to-classical crossover, leading to improved energy retention.

Contribution

It reveals that optimized decoherence can significantly extend exciton lifetime by stabilizing dark exciton populations, offering a new approach for efficient solar energy conversion.

Findings

Exciton lifetime increases by nearly two orders of magnitude.

Dark exciton population stability is key to lifetime enhancement.

Quantum-to-classical crossover is instrumental in this process.

Abstract

Energy dissipation and decoherence are at first glance harmful to acquiring long exciton lifetime desired for efficient photovoltaics. In the presence of both optically forbidden (namely, dark) and allowed (bright) excitons, however, they can be instrumental as suggested in photosynthesis. By simulating quantum dynamics of exciton relaxations, we show that the optimized decoherence that imposes a quantum-to-classical crossover with the dissipation realizes a dramatically longer lifetime. In an example of carbon nanotube, the exciton lifetime increases by nearly two orders of magnitude when the crossover triggers stable high population in the dark exciton.