All-inorganic Colloidal Perovskites Quantum Dots
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Product Description
All-inorganic colloidal perovskites quantum dots are a new class of favorable optical gain materials that combine the advantages of colloidal quantum dots and halide perovskites. Low threshold and ultra-stable excited emission are wavelength tunable in the entire visible spectral range by size or composition control under atmospheric conditions. Alfa Chemistry offers the above mentioned products in addition to custom products that are guaranteed to meet customer needs.
Applications
The CsPbX3 all-inorganic colloidal perovskite quantum dots (IPQDs) used by Yue et al. were fabricated according to a slightly modified formulation from the literature, and a series of IPQDs samples with different halide compositions and different sizes were synthesized. First, the systematic investigation was focused on CsPbBr3 IPQDs with an edge size of ≈9 nm. Figure 1a shows UV-Vis absorption and PL spectra, and Figure 1b shows transmission electron microscopy (TEM) images. The inset in Figure 1a illustrates the cubic perovskite structure of CsPbBr3 IPQDs. To explore the SE, tightly packed films of CsPbBr3 IPQDs were pumped by standard streak pumping configuration (SPC) with femtosecond laser pulses (100 fs, 1 kHz) at an optical wavelength of 400 nm. It was found that at low pump intensities (< ≈ 22 μJ·cm-2), the PL spectrum was dominated by a relatively broad spontaneous emission located at 514.5 nm (full width at half maximum (FWHM): ≈ 23 nm), while a narrower emission band at 524.5 nm with a FWHM of ≈ 5 nm appeared on the long-wave side when the pump intensity exceeded ≈ 22 μJ·cm-2. Plots of the integrated intensities of the spikes as a function of pump intensity exhibit a superlinear growth behavior, indicating the appearance of SE in these CsPbBr3 IPQDs. pump thresholds as low as ≈22 μJ·cm-2, which is one of the lowest values for colloidal QDs and nearly an order of magnitude lower than CdSe based QDs emitting in a similar spectral range. Model gain coefficients for thin films of CsPbBr3 IPQDs is estimated by variable stripe length (VSL) to be ≈ 98 cm-1 and the pump intensity to be 57. 0 μJ·cm-1, which is comparable or better than the conventional QDs (≈ 95 cm-1 for red-emitting CdSe/ZnCdS QDs at 120 μJ·cm-2 and ≈ 60 cm-1 for the corresponding green-emitting QDs at 155 μJ·cm-2).
Fig.1 a) Absorption and emission spectra of CsPbBr3 IPQDs in solution. b) TEM image of CsPbBr3 IPQDs. (Yue, 2015)
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Reference
- Yue, et al. All-Inorganic Colloidal Perovskite Quantum Dots: A New Class of Lasing Materials with Favorable Characteristics. Advanced materials (Deerfield Beach, Fla.), 2015.
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