Multibandgap quantum dot ensembles for solar-matched infrared energy harvesting

Bin Sun, Olivier Ouellette, F. Pelayo García de Arquer, Oleksandr Voznyy, Younghoon Kim, Mingyang Wei, Andrew H. Proppe, Makhsud I. Saidaminov, Jixian Xu, Mengxia Liu, Peicheng Li, James Z. Fan, Jea Woong Jo, Hairen Tan, Furui Tan, Sjoerd Hoogland, Zheng Hong Lu, Shana O. Kelley, Edward H. Sargent*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

As crystalline silicon solar cells approach in efficiency their theoretical limit, strategies are being developed to achieve efficient infrared energy harvesting to augment silicon using solar photons from beyond its 1100 nm absorption edge. Herein we report a strategy that uses multi-bandgap lead sulfide colloidal quantum dot (CQD) ensembles to maximize short-circuit current and open-circuit voltage simultaneously. We engineer the density of states to achieve simultaneously a large quasi-Fermi level splitting and a tailored optical response that matches the infrared solar spectrum. We shape the density of states by selectively introducing larger-bandgap CQDs within a smaller-bandgap CQD population, achieving a 40 meV increase in open-circuit voltage. The near-unity internal quantum efficiency in the optimized multi-bandgap CQD ensemble yielded a maximized photocurrent of 3.7 ± 0.2 mA cm−2. This provides a record for silicon-filtered power conversion efficiency equal to one power point, a 25% (relative) improvement compared to the best previously-reported results.

Original languageEnglish (US)
Article number4003
JournalNature communications
Volume9
Issue number1
DOIs
StatePublished - Dec 1 2018

ASJC Scopus subject areas

  • General
  • General Physics and Astronomy
  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology

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