Slow cooling and highly efficient extraction of hot carriers in colloidal perovskite nanocrystals

Mingjie Li, Saikat Bhaumik, Teck Wee Goh, Muduli Subas Kumar, Natalia Yantara, Michael Grätzel, Subodh Mhaisalkar, Nripan Mathews, Tze Chien Sum

Research output: Journal article publicationJournal articleAcademic researchpeer-review

151 Citations (Scopus)

Abstract

Hot-carrier solar cells can overcome the Schottky-Queisser limit by harvesting excess energy from hot carriers. Inorganic semiconductor nanocrystals are considered prime candidates. However, hot-carrier harvesting is compromised by competitive relaxation pathways (for example, intraband Auger process and defects) that overwhelm their phonon bottlenecks. Here we show colloidal halide perovskite nanocrystals transcend these limitations and exhibit around two orders slower hot-carrier cooling times and around four times larger hot-carrier temperatures than their bulk-film counterparts. Under low pump excitation, hot-carrier cooling mediated by a phonon bottleneck is surprisingly slower in smaller nanocrystals (contrasting with conventional nanocrystals). At high pump fluence, Auger heating dominates hot-carrier cooling, which is slower in larger nanocrystals (hitherto unobserved in conventional nanocrystals). Importantly, we demonstrate efficient room temperature hot-electrons extraction (up to ∼83%) by an energy-selective electron acceptor layer within 1 ps from surface-treated perovskite NCs thin films. These insights enable fresh approaches for extremely thin absorber and concentrator-type hot-carrier solar cells.

Original languageEnglish
Article number14350
JournalNature Communications
Volume8
DOIs
Publication statusPublished - 8 Feb 2017
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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