Temporal-spatial-energy resolved advance multidimensional techniques to probe photovoltaic materials from atomistic viewpoint for next-generation energy solutions

Kumar, V. Ramesh; Nisika,; Kumar, Mukesh

doi:10.1039/d1ee01165k

Cited by 13 publications

(13 citation statements)

References 389 publications

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“…In here, A 1 and A 2 refer to the decay amplitudes; B signifies a constant about the baseline offset; τ 1 is the speedy decay of trap-mediated carrier nonradiative recombination, while τ 2 tells the lagging decay associated with carrier radiative recombination. The formula τ av = ( A 1 τ 1 2 + A 2 τ 2 2 )/( A 1 τ 1 + A 2 τ 2 ) helps figure out the average PL decay times (τ ave ). , Table displays the fitted results. The lauric acid-treated film shows longer PL decay (τ av = 130.12 ns) than the pristine film (τ av = 44.24 ns); the longer carrier lifetime means the fewer carrier recombinations, which facilitate hole extraction and influence the open-circuit voltage. , …”

Section: Resultsmentioning

confidence: 99%

“…The formula τ av = ( A 1 τ 1 2 + A 2 τ 2 2 )/( A 1 τ 1 + A 2 τ 2 ) helps figure out the average PL decay times (τ ave ). , Table displays the fitted results. The lauric acid-treated film shows longer PL decay (τ av = 130.12 ns) than the pristine film (τ av = 44.24 ns); the longer carrier lifetime means the fewer carrier recombinations, which facilitate hole extraction and influence the open-circuit voltage. , …”

Section: Resultsmentioning

confidence: 99%

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Performance Improvement of Planar Perovskite Solar Cells Using Lauric Acid as Interfacial Modifier

Cai

Lin

Pan

et al. 2022

ACS Appl. Energy Mater.

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Interfacial defect passivation of perovskite active layer has become an advantageous design that can alleviate interfacial nonradiative recombination, increase the stability and improve the performance of the device. Here, lauric acid as surface passivation agent is introduced on the top of a perovskite active layer. The carboxyl group (-COOH) on lauric acid can coordinate with the Pb2+ on the perovskite and passivate interface defects, which reduces carrier nonradiative combinations and enhances the photovoltaic performance of PSCs. The saturated alkyl chain of lauric acid is covered on the perovskite films, increasingthe moisture resistance of the film and improving the environmental stability of the devices. Consequently, the lauric acid-modified device achieves a power conversion efficiency (PCE) of 21.36% with a high open-circuit voltage (V OC) of 1.181 V and an improved stability, while the pristine device attains only a PCE of 18.08% under the same condition. The results demonstrate a facile and effective strategy to passivate interfacial defects and improve the performance of PSCs by lauric acid modifying.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Performance Improvement of Planar Perovskite Solar Cells Using Lauric Acid as Interfacial Modifier

Cai

Lin

Pan

et al. 2022

ACS Appl. Energy Mater.

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“…Conventional far-field optical spectroscopies have diffraction-limited spatial resolution and are subjected to optical selection rules, thus limiting the study of the near-field response properties of plasmonic nanostructures. − Scanning near-field optical microscopy (SNOM) can overcome the diffraction limit by exploiting the properties of evanescent waves but is limited by weak light sources and poor detectors in the IR (∼1–10 μm). , Alternatively, electron-energy loss spectroscopy (EELS) performed in a scanning transmission electron microscope (STEM) can map the near-field responses of plasmonic nanostructures at high-spatial resolution (∼1 nm) across a broad spectral window in a single scan. , The evanescent waves associated with a fast traveling electron beam excite all plasmon modes, dipolar and nondipolar, allowing for the spectral- and spatial-mapping of both bright and dark plasmon modes. , Additionally, recent advancements in monochromators and direct-electron detectors now allow access to low-energy IR excitations with a high signal-to-noise ratio, enabling vibrational spectroscopy with high spatial resolution. − …”

Section: Introductionmentioning

confidence: 99%

Infrared Near-Field Spectroscopy of Gold Nanotriangle Fabry-Pérot Resonances

et al. 2023

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In this work, we characterize the near-field response of individual gold nanotriangles over a broad, visible-to-infrared, spectral region (200−1500 meV) using high-resolution electron energy-loss spectroscopy (EELS) performed inside of a scanning transmission electron microscope (STEM). We begin by experimentally imaging the spatial and spectral extent of each nanotriangle's plasmonic Fabry-Peŕot modes and measuring the evolution of their resonance energies with increasing edge length; thereby providing detailed information on infrared plasmon dephasing times and dispersion relations. Numerical electromagnetic simulations of the electron probe are used to interpret these experimental results and to compare the near-field electromagnetic enhancement factors of gold nanotriangles and nanorods of equal resonant energy. Taken together, this combined experimental and theoretical study provides unique insights relevant to designing noble metal plasmonic nanoparticle systems for solar energy harvesting and sensing applications in the near-and midinfrared.

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“…This restriction is especially severe in the mid- and far-infrared, where the wavelengths are 10–100 μm; although, extensive research efforts combined with technological advancements have yielded an ever-growing set of photon-based methods to surpass the diffraction limit. For example, near-field techniques exploit evanescent waves to achieve sub-50 nm spatial resolution , while inelastic spectroscopies such as X-ray scattering (IXS) and vibrational Raman spectroscopy can map vibrational properties of materials with 100–300 nm spatial resolution (Figure ). , Despite these impressive advancements, the subnanometer spatial resolution necessary to map the individual vibrational modes confined to small nanocrystals and material interfaces remains inaccessible using photon-based spectroscopies.…”

Section: Introductionmentioning

confidence: 99%

“…While electron energy-loss spectroscopy (EELS) is routinely applied in scanning transmission electron microscopy (STEM) to map the chemical, electronic, and plasmonic properties of materials with subnanometer spatial resolution, , STEM-EELS has historically lacked the energy resolution to resolve individual vibrational modes. In 2014, Krivanek et al employed recent advancements such as the ultrabright cold-field emission guns (FEGs), new monochromator designs, and increased energy dispersion per channel to achieve a record-breaking sub-10 meV energy resolution in a STEM.…”

Section: Introductionmentioning

confidence: 99%

Imaging Vibrational Excitations in the Electron Microscope

Kumar

Camden

2022

J. Phys. Chem. C

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Vibrational spectroscopy is a powerful tool for probing atomic motions in molecules and extended solids. Recent advances in aberration-corrected, monochromated-scanning transmission electron microscopy (STEM) now allow imaging of individual phonon modes at the nanoscale, overcoming the spatial limit imposed by diffraction-limited optical spectroscopy techniques. In this Perspective, we summarize the recent progress in high-resolution electron energy-loss spectroscopy (EELS), which now enables vibrational spectroscopy to be performed in the electron microscope. The high spatial and energy resolution of low-loss EELS can be used to directly image phonons inside or near inorganic and organic materials without considerable sample damage. Monochromated EELS can furthermore resolve isotope specific vibrational signatures and phonon modes arising from single-atom dopants. In parallel with these advances, we highlight the ability of spatial-and momentum-resolved EELS to measure the phonon dispersions at material interfaces, obtaining valuable knowledge about interfacial thermal and electrical transport phenomena. Before concluding, we illustrate how imaging infrared (IR) plasmons at high spatial resolution deepens our understanding of how plasmons interact with molecular vibrations. Taken together, these diverse studies illustrate the capability of monochromated STEM-EELS to image low-energy phonon and plasmon excitations at the nanoscale and the new insights from these studies can be leveraged to engineer the specific material properties needed for next-generation devices.

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Temporal-spatial-energy resolved advance multidimensional techniques to probe photovoltaic materials from atomistic viewpoint for next-generation energy solutions

Abstract: Solar cell technologies have attracted great attention in view of their potential to meet world’s energy demands in sustainable fashion. Extensive research efforts have been made to increase the efficiency...

Cited by 13 publications

References 389 publications

Performance Improvement of Planar Perovskite Solar Cells Using Lauric Acid as Interfacial Modifier

Performance Improvement of Planar Perovskite Solar Cells Using Lauric Acid as Interfacial Modifier

Infrared Near-Field Spectroscopy of Gold Nanotriangle Fabry-Pérot Resonances

Imaging Vibrational Excitations in the Electron Microscope

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