Correlation between Single-Photon Emission and Size of Cesium Lead Bromide Perovskite Nanocrystals

Abstract

Emission photon statistics of semiconductor nanocrystal quantum dots (QDs), including lead halide perovskite nanocrystals (PNCs), are important fundamental and practical optical properties. Single QDs exhibit high-probability single-photon emission owing to the efficient Auger recombination between generated excitons. Because the recombination rate depends on QD size, singlephoton emission probability should be size-dependent. Previous studies have researched QDs smaller than their exciton Bohr diameters (twice the Bohr radius of excitons). Here, we investigated the relationship between the single-photon emission behavior and size of CsPbBr 3 PNCs to elucidate their size threshold. Simultaneous single-nanocrystal spectroscopy and atomic force microscopy observations on single PNCs with approximately 5−25 nm edge length showed that those smaller than approximately 10 nm, which had size-dependent photoluminescence (PL) spectral shifts, exhibited high-probability single-photon emissions, which decreased linearly with PNC volume. Novel single-photon emission, size, and PL peak correlations of PNCs are important for understanding the relationship between single-photon emission and quantum confinement.

Weakly Confined Organic–Inorganic Halide Perovskite Quantum Dots as High-Purity Room-Temperature Single Photon Sources

“…On the other hand, CsPbBr 3 QDs exhibit higher g (2) (0) values and a larger spread due to their lower signal-to-noise ratio. Our results agree with a previous report 14 for CsPbBr 3 PQDs. Correspondingly, the size-and composition-dependent g (2) (τ) measurements for these PQDs using a pulsed laser (1 MHz repetition rate) are given in Figure S10.…”

“…Halide perovskites are revolutionary light-harvesting and light-emitting materials with outstanding optoelectronic properties − for solar cells and light-emitting diodes. − Of late, halide perovskite quantum dots (PQDs) have also demonstrated great promise as room-temperature (RT) single photon sources (SPSs). ,− SPSs are the basic building blocks of quantum technologies such as quantum metrology, quantum communication, and quantum computation. ,− Engineering efficient blinking-free SPSs with high purity, indistinguishability, and stability is paramount to the practical realization of these technologies. Until now, the most effective approach to achieve high-purity single photon emission with inorganic CsPb X 3 ( X = Cl, Br, or I) PQDs is through employing strong quantum confinement to enhance the Auger recombination (AR) of biexcitons. ,− ,, The metric defining the single photon purity of a SPS is the second-order intensity correlation function, g (2) (0) ≈ 4 τ XX / τ X , where g (2) (0) = 0 reflects the ideal case . Here, τ XX ( τ X ) is the biexciton (exciton) lifetime.…”

“…Until now, the most effective approach to achieve high-purity single photon emission with inorganic CsPbX 3 (X = Cl, Br, or I) PQDs is through employing strong quantum confinement to enhance the Auger recombination (AR) of biexcitons. 3,[9][10][11][12][13][14][15]22,23 The metric defining the single photon purity of a SPS is the second-order intensity correlation function, g (2) (0) ≈ 4τ XX /τ X , where g (2) (0) = 0 reflects the ideal case. 24 Here, τ XX (τ X ) is the biexciton (exciton) lifetime.…”

Self-Assembly Behavior of Perylene Bisimide Derivatives on a Perovskite Nanocrystal Surface

“…Cesium lead halide (CsPbX 3 , X = Cl, Br, I) perovskite nanocrystals (NCs) have attracted attention as outstanding light-emitting nanomaterials because of their narrow photoluminescence (PL) spectra with high PL quantum yield (PLQY) and color tunability by the size and composition. − Moreover, the NC is also expected to be used as an outstanding photosensitizer because of the large absorption cross-section and long exciton lifetimes, which can undergo singlet and triplet exciton energy transfers to acceptor molecules. − Therefore, the combination of NCs and functional organic dye molecules has been investigated for application in energy conversion materials and sensing. For example, coassemblies with pentacene molecules show efficient singlet fission via singlet energy transfer from the NC .…”

Single-Photon Emission from Organic Dye Molecules Adsorbed on a Quantum Dot via Energy Transfer

“…For single-QD-PBI measurements, QD-PBIs were dispersed in a poly­(methyl methacrylate) (PMMA) thin film on a glass coverslip. The emission properties of the single QD-PBIs were examined using an inverted confocal microscope. − A picosecond-pulsed laser at 405 or 470 nm was introduced into the microscope as an excitation light source. On the basis of the ε of the QD and PBI at 405 and 470 nm, i.e., ε QD405 = 2.6 × 10 5 M –1 cm –1 , ε QD470 = 1.1 × 10 5 M –1 cm –1 , ε PBI405 = 5.3 × 10 3 M –1 cm –1 , and ε PBI470 = 6.8 × 10 3 M –1 cm –1 , the ε QD /ε PBI ratios at 405 and 470 nm were calculated as ε QD405 /ε PBI405 = 49 and ε QD470 /ε PBI470 = 16.…”