Two-dimensional (2D) materials have been gaining growing interest because of their outstanding chemical, electrical, and physical properties. A two-dimensional (2D) material is a substance that possesses structural features predominantly in two dimensions, with thicknesses typically on the atomic or nanometer scale. These materials exhibit unique properties due to their reduced dimensionality, such as high surface area-to-volume ratios, exceptional electronic, optical, and mechanical properties. Examples of 2D materials include graphene, transition metal dichalcogenides (TMDs) like MoS2, hexagonal boron nitride (h-BN), and black phosphorus (phosphorene). Recently, numerous research groups have uncovered the synergistic effects derived from the combination of 2D materials and organic-inorganic hybrid perovskite materials in solar cell applications [1]
Organic-inorganic hybrid perovskites have garnered global interest as solar energy absorbers, thanks to their exceptional photovoltaic characteristics- These include a highly adjustable bandgap, strong absorption capability, low exciton binding energy, excellent charge mobility, extended carrier lifespan, and far-reaching charge diffusion distances. Over the past decade, the rapid expansion of research on perovskite solar cells (PSCs) has led to the development of multiple device structures, notably mesoscopic and planar designs. Unlike planar PSCs, which have been extensively studied, mesoscopic PSCs feature an additional porous layer that acts as a support structure for the perovskite absorber, enhancing charge collection efficiency. While mesoscopic structures are preferred for achieving high-efficiency PSCs, planar PSCs hold promise due to their ability to be processed at low temperatures and compatibility with flexible substrates [2].
The large absorption coefficient, flexibility, tunable band gap, high open-circuit voltage and higher power conversion efficiencies of the perovskite solar cell make it most suitable for the conversion of solar energy into electrical energy. With perovskite solar cells already achieving efficiencies surpassing 20%, current research efforts are focusing on fine-tuning band gaps, enhancing thermal stability, and mitigating moisture-related issues.
It was observed that the perovskite thin film displays higher absorption in the ultraviolet (UV) and visible regions to the near-infrared (NIR) region [3].
To determine the precise absorption characteristics of the perovskite, experimental techniques such as photoluminescence spectroscopy can be employed. These techniques can provide detailed information about the absorption spectrum of the material, bandgap energy, defects and trap states, carrier dynamics, exciton properties and environmental effects [4].
Through photoluminescence spectroscopy, information about excitons can be obtained, such as bandgap energy, exciton binding energy, material purity and exciton lifetime, emission efficiency and quenching effects.
Iceblink Supercontinuum Fiber Laser could significantly enhance photoluminescence spectroscopy of perovskite materials and, in general, 2D materials. The wide spectral range, high total power, visible range power, rapid repetition rate, and excellent power stability of Iceblink make it an ideal light source for enhancing photoluminescence spectroscopy of perovskite, enabling detailed investigation of their optical properties and photoluminescence behavior.
Experimental Set-up
In this experimental setup, our Supercontinuum Fiber Laser (Iceblink) serves as the excitation source. The laser beam is directed using mirrors towards the rest of the optical components. A dichroic mirror separates the excitation light from the emitted photoluminescence signal.
The excitation light is focused onto the sample using a parabolic mirror, ensuring optimal excitation intensity. The sample, a perovskite film or crystal, absorbs the excitation light and emits photoluminescence signals characteristic of its optical properties.
The emitted photoluminescence signals are collected and measured by a photon detector, which may be a photomultiplier tube (PMT) or avalanche photodiode (APD). Counting electronics process the detector signals, converting them into digital counts for analysis.
Optical filters may be used to selectively filter out unwanted wavelengths or background noise from the photoluminescence signals, improving the signal quality and spectral purity.
Supercontinuum Fiber Laser for Photoluminescence Spectroscopy of Perovskite
Our Iceblink Supercontinuum Fiber Laser could significantly enhance photoluminescence spectroscopy of perovskite materials because of:
- Wide spectral range: the spectral range of 450-2300 nm covers a broad range of wavelengths, allowing for comprehensive analysis of the perovskite material’s photoluminescence emission. This wide range enables researchers to study the entire emission spectrum of the material, including any emission peaks or features that may occur at different wavelengths.
- Visible range power: the visible range power of 150 mW ensures adequate excitation power specifically in the visible wavelength range, which is where the photoluminescence emission of perovskite materials occurs. This facilitates efficient excitation of the perovskite sample and enhances the detection of photoluminescence signals in the visible spectrum.
- High total power: with a total power exceeding 3 W, the Iceblink provides sufficient optical power for excitation of the perovskite sample during PL spectroscopy. Higher power levels result in stronger excitation of the material, leading to increased signal-to-noise ratio and improved detection sensitivity in the PL measurements.
- Repetition rate: the repetition rate of 80 MHz enables rapid data acquisition during photoluminescence spectroscopy measurements. This high repetition rate allows for fast scanning of the emission spectrum and efficient collection of photoluminescence data, reducing measurement time and increasing experimental throughput.
- Power stability: The low power stability (<0.5% standard deviation) ensures consistent and reliable excitation of the perovskite sample over extended periods. This stability minimizes fluctuations in excitation intensity, leading to more reproducible photoluminescence measurements and improved accuracy of the obtained spectral data.
These features make our Supercontinuum Fiber Laser, the Iceblink, an ideal light source for enhancing photoluminescence spectroscopy of perovskite materials, enabling detailed investigation of their optical properties and photoluminescence behavior.
Bibliography
[1] P. You, G. Tang, and F. Yan, “Two-dimensional materials in perovskite solar cells,” Materials Today Energy, vol. 11. Elsevier Ltd, pp. 128–158, Mar. 01, 2019. doi: 10.1016/j.mtener.2018.11.006.
[2] A. S. R. Bati, M. Batmunkh, and J. G. Shapter, “Emerging 2D Layered Materials for Perovskite Solar Cells,” Adv Energy Mater, vol. 10, no. 13, Apr. 2020, doi: 10.1002/aenm.201902253.
[3] M. Pandey, D. Hamal, B. Basnet, and B. Kafle, “SYNTHESIS AND OPTICAL CHARACTERIZATION OF PEROVSKITE LAYER FOR SOLAR CELL APPLICATION,” 2022. [Online]. Available: http://www.ijeast.com
[4] T. Kirchartz, J. A. Márquez, M. Stolterfoht, and T. Unold, “Photoluminescence-Based Characterization of Halide Perovskites for Photovoltaics,” Advanced Energy Materials, vol. 10, no. 26. Wiley-VCH Verlag, Jul. 01, 2020. doi: 10.1002/aenm.201904134.
[5] K. Eremeev et al., “ Growth, spectroscopy and laser operation of Tm,Ho:GdScO 3 perovskite crystal ,” Opt Express, vol. 32, no. 8, p. 13527, Apr. 2024, doi: 10.1364/oe.518709.
