Different roles of quantum interference in a quantum dot photocell with two intermediate bands
- PDF / 1,069,907 Bytes
- 10 Pages / 439.37 x 666.142 pts Page_size
- 76 Downloads / 182 Views
Different roles of quantum interference in a quantum dot photocell with two intermediate bands Shun-Cai Zhaoa
, Jing-Yi Chen, Xin Li
Department of Physics, Faculty of Science, Kunming University of Science and Technology, Kunming 650500, People’s Republic of China Received: 14 July 2020 / Accepted: 3 November 2020 © Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract It is generally believed that quantum interference can improve the transport of photo-generated carriers in a photocell, thereby improve the photoelectric conversion efficiency. In this work, we explicitly explore different roles of quantum interferences in the photoelectric conversion efficiency in a quantum dot (QD) photocell with two intermediate bands. The increasing transition rates from different charge transport channels bring out first increasing, then decreasing, and then monotonically decreasing photoelectric conversion efficiencies. And the photoelectric conversions increase with quantum coherence generated by the upper transition rates owing to their robust quantum interference. However, the conversion efficiency decreases with the quantum interference induced by two lower-transition rates due to the shortened population lifetime in the intermediate bands. These results provide insight into different roles of quantum interferences in photoelectric conversion efficiency, and may provide some artificial strategies to achieve efficient photoelectric conversion via the adjusted quantum interferences in a QD photocell with multi-intermediate bands.
1 Introduction The efficiency of photoelectric conversion in a single bandgap solar cell is fundamentally limited to 31% because of the efficiency loss caused by the detailed balance limit [1]. And the types of efficiency loss can be divided into two distinct categories under one sun illumination. One is the extrinsic losses, such as series resistance [2–4], parasitic recombination and contact shadowing [5,6], they are theoretically avoidable and consequently are not considered in fundamental limiting efficiency. The other is the intrinsic losses, such as non-absorption of photons with energy below the bandgap [7–9], thermalization loss [10–13] due to strong interaction between excited carriers and lattice phonons, and emission loss according to Kirchoff‘s law [14,15], they are unavoidable in device design and will still be present in an idealized solar cell [16]. Therefore, the intermediate band solar cell [17–19] was proposed to overcome some fundamental limitation by introducing a radiative efficiency but electrically isolated band between the conduction and valence bands [20–22]. Recently, some researches manifest that [23–25] the detailed balance can be broken by quantum coherence induced by the intermediate band transitions, which achieves the
a e-mail: [email protected] (corresponding author)
0123456789().: V,-vol
123
892
Page 2 of 10
Eur. Phys. J. Plus
(2020) 135:892
enhanced quantum efficiency in a photocell [26]. As far as we know
Data Loading...
