Tuning of Amplified Spontaneous Emission Wavelength for Green and Blue Light Emission through the Tunable Composition of CsPb(Br_1–xCl_x)₃ Inorganic Perovskite Quantum Dots

Abstract

Perovskite quantum dots (PQDs) have emerged as promising competitive materials for optoelectronics and future energy applications. In this work, high-quality PQD thin films fabricated directly from the powdered form of CsPb(Br 1−x Cl x ) 3 compositions were investigated. Tunable light emission was achieved via (in general) composition modulation through a mixed halide (chloride/bromide) with different ratios of Cl-ion substitution of Br ions. The structural properties of the various compositions (alloys) as a function of the Cl content were investigated. These properties were correlated with the emitting colors and amplified spontaneous emission (ASE)/lasing performance, and the potential application of these properties in lighting devices and other optoelectronics devices was verified. These alloys consisted of a highly stable cubic phase that remained stable even at room temperature because of direct synthesis at a high temperature for all compositions. The Cl content had only a slight effect on the QD size. Moreover, the bandgaps of the alloys exhibited a strong dependence on the composition and increased rapidly with changing Br-to-Cl ratio through the halide ion exchange process. Furthermore, compositionally, the perovskite alloy was a photostable material and exhibited excellent photoluminescence quantum yields (PLQYs) and considerable photoluminescence. Alloys with a high Cl content underwent significant nonradiative decay, and the PLQYs decreased with increasing bandgap. These features were all dependent on ligand exchange from Br to Cl. In addition, ASE properties of these composition films were achieved and compared under long-term ambient conditions. Moreover, a low ASE threshold (21, 45, and 53 μJ/cm 2 for x = 0, 0.25, and 0.40, respectively) was obtained under picosecond laser excitation.

Density Functional Theory Analysis of Structural, Electronic, and Optical Properties of Mixed-Halide Orthorhombic Inorganic Perovskites

“…The mBJ-GGA method demonstrated the evolution of band structure, optical absorption, and energy band gap ( E g ) with increasing x in CsPb­(I 1– x Br x ) 3 and CsPb­(Br 1– x Cl x ) 3 . The lattice constants and E g were computed and found to be consistent with previous research. ,,,,,,,,,− Furthermore, the effective masses of charge carriers, absorption, optical dielectric, and reflectivity were precisely calculated.…”

Colloidal CdSe/CdS Core/Crown Nanoplatelets for Efficient Blue Light Emission and Optical Amplification

“…This number is consistent with the reported amplified spontaneous emission thresholds for blue-emitting CdSe (50 μJ/cm 2 ), or CdS and CdS/ZnS NPLs (50–250 μJ/cm 2 ), and is significantly lower than typical thresholds for blue quantum dots (∼1 mJ/cm 2 ) ,, unless the latter are carefully engineered to introduce a smooth confinement potential, which reduces the threshold to 60 μJ/cm 2 . Moreover, our values are comparable to typical thresholds (63–190 μJ/cm 2 ) reported for blue-emitting perovskite nanostructures. − …”

Metal Halide Perovskites toward Electrically Pumped Lasers

“…8 2019 [177] CsPb 2 Br 5 microplates 800 nm, 35 fs, 1 kHz 300 538 243 4 >9 × 10 6 2020 [178] CsPbBr 3 QDs-Au core/shell 400 nm, 120 fs, 1 kHz RT 542 5 k 5.5 2020 [146] CsPbBr 3 single crystal films 400 nm, 100 fs, 1 kHz RT 540 8 3.3 1255 ± 160 2020 [150] PEA 2 FA n −1 Pb n Br 3 n+1 thin films 337 nm, 3 ns, 20 Hz RT 550 33.1 4 2020 [24] NMA 2 FA n −1 Pb n Br 3 n+1 thin films 337 nm, 3 ns, 20 Hz RT 555 16.7 4 2020 [24] MAPbBr 3 thin films 400 nm, 200 fs, 1 kHz ≈100 2020 [101] BA 3 MA 3 Pb 5 Br 16 thin films 337 nm, 3 ns, 20 Hz 13-230 554 0.18-5.8 k 2021 [179] CsPbBr 2021 [180] CsPb(Br 0.75 Cl 0.25 ) 3 QDs 355 nm, 70 fs, 15 Hz RT 498 45 6.71 2021 [180] CsPb(Br 0.6 Cl 0.4 ) 3 QDs 355 nm, 70 fs, 15 Hz RT 468 53 6.15 2021 [180] CsPbBr 3 microrods 343 nm, 290 fs, 1 kHz RT 543 10.2 10 2021 [181] PEA 2 (CsPbBr 3 ) n −1 PbBr 4 thin films 400 nm, 120 fs, 1 kHz 800 nm, 120 fs, 1 kHz 532 11.7 7.2k ≈4 622 2022 [182] CsPbBr 3 QDs inside a transparent glass 400 nm, 50 fs, 1 kHz 78-RT ≈530 7.4-100.4 ≈4 627.9-98 >12 h 2022 [183] CsPbCl 1.5 Br 1.5 thin films 355 nm, 80 fs, 1 kHz 480 6.5 5 2022 [184] but also injected into a cylindrical microcapillary tube to establish a ring cavity, [78,83,111] as shown in Figure 4d,e. Although the low lasing threshold is charming, single-mode lasers are still the further goal for their practical applications in on-chip optical processing, communication, and data storage.…”