Halide perovskites are extremely interesting semiconductors for innovative optoelectronics devices and sensors. In particular, being direct band-gap semiconductors, they are efficient emitters of both incoherent and coherent light [1]. Therefore the possibility of use as active medium in lasers, light amplification systems (resonators and waveguides) and other photonic devices is driving a large part of research in these years [2]. Among inorganic halide perovskites, CsPbBr3 is of interest because of its efficient green emission ( ≈2.3 eV) which makes it a valid substitute of indium-gallium nitrides to solve the green gap problem. In this contribution we present experimental results concerning the light emission in a set of CsPbBr3 films deposited, by spin-coating, on a silicon substrate and on metasurfaces realized by micro/nanospheres having a core of SiO2 and a shell of TiO2 (T-Rex ) on a silicon substrate [3]. Samples were excited after continuous wave laser excitation at 405 nm and with 300 ps long pulses at 266 nm. We investigate both the linear regime, typical of photoluminescence, and the non-linear regime bringing clear evidence of the presence of Amplified Stimulated Emission (ASE) up to 200 K in a back-scattering geometry without the need of a waveguide configuration ( see Figure_PL_and_ASE_CsPbBr3). Depending on the sample structure and increasing the excitation density a transition from the superlinear regime to a linear/sublinear regime is revealed. The significant differences found between samples, differing in their morphology, allow to distinguish between anamplification due to randomly arranged emitters and an amplification due to quite ordered nanocrystals. In particular an enhancement of the photoluminescence and ASE is found when nanocrystals are arranged on the T-Rex indicating a major role played by the metasurfaces in the light extraction. [1] X. Li et al.: “All inorganic halide perovskites nanosystem: Synthesis, structural features, optical properties and optoelectronic applications”, Small 13, 1603996 (2017). [2] see “Halide Perovskites for Photonics”, edited by A. Vinattieri and G. Giorgi (AIP Publishing, New York, 2021). [3] I. Alessandri, “Enhancing raman scattering without plasmons: Unprecedented sensitivity achieved by TiO2 shell-based resonators”, Journal of the American Chemical Society 135, 5541–5544 (2013)
Amplified Spontaneous Emission in CsPbBr_3 Decorated Metasurfaces
Giammarco Roini;Ivano Alessandri;
2022-01-01
Abstract
Halide perovskites are extremely interesting semiconductors for innovative optoelectronics devices and sensors. In particular, being direct band-gap semiconductors, they are efficient emitters of both incoherent and coherent light [1]. Therefore the possibility of use as active medium in lasers, light amplification systems (resonators and waveguides) and other photonic devices is driving a large part of research in these years [2]. Among inorganic halide perovskites, CsPbBr3 is of interest because of its efficient green emission ( ≈2.3 eV) which makes it a valid substitute of indium-gallium nitrides to solve the green gap problem. In this contribution we present experimental results concerning the light emission in a set of CsPbBr3 films deposited, by spin-coating, on a silicon substrate and on metasurfaces realized by micro/nanospheres having a core of SiO2 and a shell of TiO2 (T-Rex ) on a silicon substrate [3]. Samples were excited after continuous wave laser excitation at 405 nm and with 300 ps long pulses at 266 nm. We investigate both the linear regime, typical of photoluminescence, and the non-linear regime bringing clear evidence of the presence of Amplified Stimulated Emission (ASE) up to 200 K in a back-scattering geometry without the need of a waveguide configuration ( see Figure_PL_and_ASE_CsPbBr3). Depending on the sample structure and increasing the excitation density a transition from the superlinear regime to a linear/sublinear regime is revealed. The significant differences found between samples, differing in their morphology, allow to distinguish between anamplification due to randomly arranged emitters and an amplification due to quite ordered nanocrystals. In particular an enhancement of the photoluminescence and ASE is found when nanocrystals are arranged on the T-Rex indicating a major role played by the metasurfaces in the light extraction. [1] X. Li et al.: “All inorganic halide perovskites nanosystem: Synthesis, structural features, optical properties and optoelectronic applications”, Small 13, 1603996 (2017). [2] see “Halide Perovskites for Photonics”, edited by A. Vinattieri and G. Giorgi (AIP Publishing, New York, 2021). [3] I. Alessandri, “Enhancing raman scattering without plasmons: Unprecedented sensitivity achieved by TiO2 shell-based resonators”, Journal of the American Chemical Society 135, 5541–5544 (2013)I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
