Trion formation hampers single quantum dot performance in silane-coated FAPbBr3 quantum dots

Journal article : Letter

We explore silane-coated formamidinium lead bromide (FAPbBr₃) quantum dots (QDs) as single photon emitters and compare them to FAPbBr₃ QDs passivated with a phosphoethylammonium derivative (PEAC₈C₁₂), which represents current state-of-the-art ligand passivation. We compare properties including single-photon purity (g⁽²⁾(τ)), line width, blinking, and photostability. We find that at room temperature, these silane-coated dots perform comparably to PEAC₈C₁₂-passivated dots, while exhibiting improvements in photostability. However, we find that at 4 K, silane-coated FAPbBr₃ QDs perform worse than the PEAC₈C₁₂-passivated samples, exhibiting faster blue-shifting and photobleaching under illumination. Analysis of fluorescence lifetime intensity distributions from the photon-counting data indicates increased efficiency of fast nonradiative processes in the silane-coated QDs at 4 K. We propose a trion-related degradation pathway at low temperatures that is consistent with the observed kinetics and estimate that at 4 K with 6.1 μJ/cm², 472 nm excitation the silane-coated QDs build up double the trion population of their PEAC₈C₁₂-passivated counterparts.

Authors: Kline, J; Kar, S; Hammel, BF; Huang, Y; Huang, Z

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Chemical Society
• Journal: Nano Letters
• Volume: 26
• Issue: 14
• Pages: 4855-4865
• Place of publication: United States
• Publication date: 2026-04-06
• Acceptance date: 2026-03-16
• DOI: 10.1021/acs.nanolett.6c00643
• EISSN: 1530-6992
• ISSN: 1530-6984
• Pmid: 41940683
• Language: English
• Keywords: photoluminescence; blinking; perovskite; quantum dot; ligand; trion
• Subtype: Letter