Enhanced Performance of Two-Photon Excited Amplified Spontaneous Emission by Cd-Alloyed CsPbBr₃ Nanocrystals

Abstract

It has been demonstrated that the alloyed perovskite nanocrystals (NCs) with a small amount of Cd element may passivate the inherent halide vacancies in perovskite NCs and improve their stability. However, the study of the optical properties of such alloyed perovskite NCs still remains essentially untouched, which will seriously hinder relevant applications. Herein, using different amounts of CdBr 2 as an alloyed metal precursor, a series of CsPb x Cd 1−x Br 3 NCs (x = 1, 0.93, and 0.88) were synthesized. Compared with bare CsPbBr 3 NCs, the Cd-alloyed NCs exhibited a near-unity photoluminescence quantum yield (99%), efficiently improved stability, and enhanced electron−phonon coupling strength. As the Cd-alloyed amount was increased, their hot-carrier cooling time became faster and the exciton−biexciton interaction decreased, causing a decreased threshold of two-photon excited amplified spontaneous emission (ASE) from 1.58 to 1.23 mJ cm −2 . In addition, the Cd-alloying method can also improve the photostability of ASE, resulting in the initial ASE intensity remaining at 90% even after 7.5 × 10 5 pulse shots. This work implies that the Cd-alloyed CsPbBr 3 NCs will be promising for application in a laser gain medium.

CsPbBr3:Mn Nanowires: d-d Transfer of Mn Ions for Bright White Emitting Diodes

“…Examples include polarized light emission, variable bandgap, large photoabsorption cross section, high stability, favorable electrical conductivity, and excellent adaptability to flexible devices, which make 1D perovskites a potential choice for LED materials. Furthermore, the PL properties of CsPbBr 3 nanomaterials were adjusted by impurity doping (e.g., Cd, Sn, Ca, Mn, Sb, and Bi). − Among them, Mn has the same coordination with Pb, which can stabilize the crystal structure of the perovskite and play a role in regulating the photoelectronic properties . More importantly, highly stable Mn-doped CsPbBr 3 has been widely studied to produce white light emission due to its unique energy conversion and dual emission .…”

InP Semiconductor Nanocrystals: Synthesis, Optical Properties, and Applications

“…[63] Beside the bandgap, temperature has effects on the emission band width, emission intensity, and decay time of semiconductor NCs. [72] Moreover, special emissions may only be observed at low temperatures, such as localized exciton emission. [73] In 2009, the temperature-dependent PL spectra were reported for four InP/ZnS NCs with different sizes by Zaag et al Fluorescence redshift due to lattice expansion was observed in InP/ZnS NCs with the increase of temperature from 2 to 525 K (Figure 6a).…”

“…The temperature dependent emission linewidth of InP/ZnS NCs in the range of 2-525 K is shown in Figure 6c. The results can be fitted by the following equation [72,76]…”

Bloch-Surface Plasmon Polariton Enhanced Amplified and Directional Spontaneous Emission from Plasmonic Hexagonal Nanohole Array

“…As a typical light emission phenomenon in optical system, amplified spontaneous emission (ASE) is obviously different from spontaneous emission, which is a characteristic before the laser oscillation threshold and depends strongly on the propagation direction. − It becomes progressively important as a competitor or even a substitute of lasing and pulsed source in optical amplifiers. The optical gain media for generating ASE is highly selective, such as optically pumped dye molecules, quantum dots, , excitons, and electrically pumped quantum wells . Future implementation in optoelectronic devices urges more effective approaches to further enhance the light emission intensity, narrow the emission band, and reduce the threshold of the ASE.…”

“…11−13 It becomes progressively important as a competitor or even a substitute of lasing and pulsed source in optical amplifiers. The optical gain media for generating ASE is highly selective, such as optically pumped dye molecules, 14 quantum dots, 15,16 excitons, 17 and electrically pumped quantum wells. 18 Future implementation in optoelectronic devices urges more effective approaches to further enhance the light emission intensity, narrow the emission band, and reduce the threshold of the ASE.…”