Highly Efficient MAPbI3‐Based Quantum Dots Exhibiting Unusual Nonblinking Single Photon Emission at Room Temperature

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 18; pp. e2308676 - n/a
• Main Authors: Chuang, Yung‐Tang, Lin, Tzu‐Yu, Tan, Guang‐Hsun, Jan, Pei‐En, Lin, Hao‐Cheng, Chen, Hung‐Ming, Hsiao, Kai‐Yuan, Chen, Bo‐Han, Lu, Chih‐Hsuan, Lee, Chi‐Hsuan, Pao, Chun‐Wei, Yang, Shang‐Da, Lu, Ming‐Yen, Lin, Hao‐Wu
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.05.2024
• Subjects: Absorption; Blinking; Electron irradiation; emission blinking; Emitters; Excitons; Fluence; halide perovskite; Optoelectronics; Perovskites; Photoluminescence; Photon emission; Photons; Purity; Quantum dots; quantum emitter; Room temperature; single photon source
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202308676

Highly emissive semiconductor nanocrystals, or so‐called quantum dots (QDs) possess a variety of applications from displays and biology labeling, to quantum communication and modern security. Though ensembles of QDs have already shown very high photoluminescent quantum yields (PLQYs) and have been widely utilized in current optoelectronic products, QDs that exhibit high absorption cross‐section, high emission intensity, and, most important, nonblinking behavior at single‐dot level have long been desired and not yet realized at room temperature. In this work, infrared‐emissive MAPbI3‐based halide perovskite QDs is demonstrated. These QDs not only show a ≈100% PLQY at the ensemble level but also, surprisingly, at the single‐dot level, display an extra‐large absorption cross‐section up to 1.80 × 10−12 cm2 and non‐blinking single photon emission with a high single photon purity of 95.3%, a unique property that is extremely rare among all types of quantum emitters operated at room temperature. An in‐depth analysis indicates that neither trion formation nor band‐edge carrier trapping is observed in MAPbI3 QDs, resulting in the suppression of intensity blinking and lifetime blinking. Fluence‐dependent transient absorption measurements reveal that the coexistence of non‐blinking behavior and high single photon purity in these perovskite QDs results from a significant repulsive exciton‐exciton interaction, which suppresses the formation of biexciton, and thus greatly reduces photocharging. The robustness of these QDs is confirmed by their excellent stability under continuous 1 h electron irradiation in high‐resolution transmission electron microscope inspection. It is believed that these results mark an important milestone in realizing nonblinking single photon emission in semiconductor QDs. MAPbI3 perovskite quantum dots demonstrate remarkable robustness under electron irradiation and photon excitation. They exhibit a high near‐infrared emission quantum yield of up to ≈100% and an unprecedented non‐blinking single photon emission at room temperature. These characteristics promise unique potential in the fields of quantum information and bioimaging.