Enhanced femtosecond nonlinear optical response in Mn-doped Cs₂AgInCl₆ nanocrystals

Abstract

Lead-free halide double perovskite nanocrystals (DPNCs) are emerging materials, recently explored as potential candidates in light-emitting, photovoltaic, and other optoelectronic applications. This Letter reveals unusual photophysical phenomena and nonlinear optical (NLO) properties of Mn-doped Cs2AgInCl6 nanocrystals (NCs) via temperature-dependent photoluminescence (PL) and femtosecond Z-scan measurements. The PL emission measurements suggest that self-trapped excitons (STEs) are present, and more than one STE state is possible for this doped double perovskite. We observed enhanced NLO coefficients, owing to the improved crystallinity arising from the Mn doping. From the closed aperture Z-scan data, we have calculated two fundamental parameters, Kane energy (29 eV) and exciton reduced mass (0.22m0). We further obtained the optical limiting onset (1.84 mJ/cm2) and figure of merit as a proof-of-concept application to demonstrate the potential in optical limiting and optical switching applications. Highlighting the self-trapped excitonic emission and NLO applications, the multifunctionality of this material system is demonstrated. This investigation provides an avenue to design novel photonic and nonlinear optoelectronic devices.

Temperature-Dependent Structure–Property Relationship of Mn-Doped Cs2AgInCl6 Thin Films Impacts Its Application as a Self-Powered UV Photodetector

“…As per the transmission electron microscopy (TEM) analysis shown in Figure 1(a) and (b), both the pristine and Mn-doped nanocrystals are cubic structured and we have observed that, after doping with the Mn, the NCs size has reduced from 14 to 10 nm which helps in achieving higher quantum efficiency in the latter compared with pristine owing to higher quantum confinement of nanocrystals with reduced size. 44 The UV−visible absorption spectrum is shown in Figure 1(c), and the obtained data matches exactly with the previous literature. 43 The schematic diagram for the preparation of thin films is shown in Figure 1(d), and as shown in the figure, the obtained colloidal NCs are dispersed in toluene with continuous stirring on a hot plate until it dissolves completely.…”

“…The synthesized pristine and Mn-doped double perovskite NCs (DPNCs) are confirmed by using basic structural and photophysical characterization techniques. As per the transmission electron microscopy (TEM) analysis shown in Figure (a) and (b), both the pristine and Mn-doped nanocrystals are cubic structured and we have observed that, after doping with the Mn, the NCs size has reduced from 14 to 10 nm which helps in achieving higher quantum efficiency in the latter compared with pristine owing to higher quantum confinement of nanocrystals with reduced size . The UV–visible absorption spectrum is shown in Figure (c), and the obtained data matches exactly with the previous literature …”

“…Afterward, the emission peaks are shifted to 558, 584, and 632 nm for 150, 200, and 250 °C annealed samples with slight variations in intensity and fwhm. From our earlier report, 44 it is known that the PL emission obtained from CAIC NCs are through self-trapped excitons (STE). The observed PL emission peak shifting with annealing temperatures could be ascribed to changes in the energetics of STE states.…”

Novel metallated imidazole phthalocyanines: synthesis, ultrafast excited-state carrier dynamics and multiphoton absorption properties

“…In the Z-scan experiments, a standard setup 27–31 was used with the Ti:sapphire laser amplifier (LIBRA) as the light source, emitting at a 800 nm central wavelength, with a 70 fs pulse duration, and a 1 kHz repetition rate. The estimated peak intensity was about 180 GW cm −2 .…”

Harnessing Coherent Light–Matter Interactions for All-Optical Switching and Logic Gate Applications with Macrocyclic Phthalocyanines

“…NLO deals with the study of the variation of the polarization density with the incident electric field of light. Since the last few decades, the NLO field has been developed in photonics and optoelectronics, including electro-optic sensors, and telecommunications. − Along with inorganic materials, − organic materials also show good NLO properties due to their highly delocalized π-conjugated electrons. ,− The organic molecules possess large and fast nonlinear responses with easy processing, providing advantages for optical applications . Due to the nonlinear Kerr effect, the NLO parameter nonlinear refractive index (NLR) n 2 of material changes with varying the value of the input intensity of the incident light. , There are various processes for measuring the third-order polarizabilities, such as four-wave mixing (FWM), the optical Kerman method, and the Z-scan method. − Nonlinear coherent light–matter interaction spatial self-phase modulation , is an easy-to-handle but robust standard experiment to precisely evaluate various NLO parameters such as nonlinear refractive index ( n 2 ) and third-order nonlinear optical susceptibility [χ (3) ].…”