Vibrational frequencies and intramolecular forces in anionic tin-halogen complexes and related species

Wharf, Ivor; Shriver, Duward F.

doi:10.1021/ic50074a042

Cited by 68 publications

(15 citation statements)

References 4 publications

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“…4a). The [SnI6] 2octahedra in Cs2SnI6 has six typical symmetric stretching vibration modes (ν1~ν6), among which ν1, ν2, and ν5 modes are Ramanactive, which are all observed here [32]. But the ν5 mode at very low wave number is a little different to the pure theoretical prediction [33].…”

Section: Resultsmentioning

confidence: 66%

From unstable CsSnI3 to air-stable Cs2SnI6: A lead-free perovskite solar cell light absorber with bandgap of 1.48 eV and high absorption coefficient

Qiu

Cao

Yuan

et al. 2017

Solar Energy Materials and Solar Cells

451

340

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All-inorganic and lead-free cesium tin halides (CsSnX3, X=Cl, Br, I) are highly desirable for substituting the organolead halide perovskite solar cells. However, the poor stability of CsSnX3 perovskites has so far prevented the fabrication of devices that can withstand sustained operation under normal conditions. In this paper, a two-step sequential deposition method is developed to grow high-quality B-γ-CsSnI3 thin films and their unique phase change in atmosphere is explored in detail. We find the spontaneous oxidative conversion from unstable B-γ-CsSnI3 to air-stable Cs2SnI6 in air. Allowing the phase conversion of the CsSnI3 film to evolve in ambient air it gives the semiconducting perovskite Cs2SnI6 with a bandgap of 1.48 eV and high absorption coefficient (over 10 5 cm-1 from 1.7 eV). More importantly, the Cs2SnI6 film, for the first time, is adopted as a light absorber layer for a lead-free perovskite solar cell and a preliminary estimate of the power conversion efficiency (PCE) about 1% with open-circuit voltage of 0.51 V and short-circuit current of 5.41 mA/cm 2 is realized by optimizing the perovskite absorber thickness. According to the bandgap and the Shockley-Queisser limit, such inorganic perovskite solar cell with higher efficiency and pronounced stability can be expected by material quality improvement and device engineering.

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Section: Resultsmentioning

confidence: 66%

From unstable CsSnI3 to air-stable Cs2SnI6: A lead-free perovskite solar cell light absorber with bandgap of 1.48 eV and high absorption coefficient

Qiu

Cao

Yuan

et al. 2017

Solar Energy Materials and Solar Cells

451

340

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“…The Cs 2 SnX 6 (X = Cl, Br, I) perovskites have not been systematically studied for their vibrational properties except for some early spectroscopic analyses, − which report only far-IR transmission spectra and no Raman spectra for Cs 2 SnI 6 . Group theory predicts the following normal modes of vibrations: …”

Section: Resultsmentioning

confidence: 99%

Optical-Vibrational Properties of the Cs₂SnX₆(X = Cl, Br, I) Defect Perovskites and Hole-Transport Efficiency in Dye-Sensitized Solar Cells

et al. 2016

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We report the vibrational and optical properties of the 'defect' perovskites Cs 2 SnX 6 (X = Cl, Br, I) as well as their use as hole-transporting materials (HTMs) in solar cells. All three air-stable compounds were characterized using powder X-ray diffraction and Rietveld refinement. Far-IR reflectance, Raman, and UV−vis spectroscopy as well as electronic band structure calculations show that the compounds are direct band gap semiconductors with a pronounced effect of the halogen atom on the size of the energy gap and the vibrational frequencies. Scanning electron microscopy and atomic force microscopy confirmed that the morphology of the perovskite films deposited from N,N-dimethylformamide solutions on TiO 2 substrates also strongly depends on the chemical composition of the materials. The Cs 2 SnX 6 perovskites were introduced as hole-transporting materials in dye-sensitized solar cells, based on mesoporous titania electrodes sensitized with various organic and metal−organic dyes. The solar cells based on Cs 2 SnI 6 HTM and the Z907 dye performed best with a maximum power conversion efficiency of 4.23% at 1 sun illumination. The higher performance of Cs 2 SnI 6 is attributed to efficient charge transport in the bulk material and hole extraction at the perovskite-Pt interface, as evidenced by electrochemical impedance spectroscopy.

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“…[ 17,30 ] Besides, Cl − can fill in the oxygen vacancies due to electrostatic coupling, thus passivating the oxygen vacancies. [ 37,38 ] On the other hand, the strong hydrogen bond will be formed between NH 2 /NH 3 + and I/I − in BGCl and PbI 2 , respectively, probably leading to an in situ like crystallization process of perovskite. [ 39 ] Accordingly, XPS and FTIR are employed to confirm the interaction between BGCl and SnO 2 /PbI 2 .…”

Section: Discussionmentioning

confidence: 99%

Simultaneous Interfacial Modification and Crystallization Control by Biguanide Hydrochloride for Stable Perovskite Solar Cells with PCE of 24.4%

et al. 2022

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Interfacial modification, which serves multiple roles, is vital for the fabrication of efficient and stable perovskite solar cells. Here, a multifunctional interfacial material, biguanide hydrochloride (BGCl), is introduced between tin oxide (SnO2) and perovskite to enhance electron extraction, as well as the crystal growth of the perovskite. The BGCl can chemically link to the SnO2 through Lewis coordination/electrostatic coupling and help to anchor the PbI2. Better energetic alignment, reduced interfacial defects, and homogeneous perovskite crystallites are achieved, yielding an impressive certified power conversion efficiency (PCE) of 24.4%, with an open‐circuit voltage of 1.19 V and a drastically improved fill factor of 82.4%. More importantly, the unencapsulated device maintains 95% of its initial PCE after aging for over 500 h at 20 °C and 30% relative humidity in ambient conditions. These results suggest that the incorporation of BGCl is a promising strategy to modify the interface and control the crystallization of the perovskite, toward the attainment of highly efficient and stable perovskite solar cells as well as other perovskite‐based electronics.

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Vibrational frequencies and intramolecular forces in anionic tin-halogen complexes and related species

Cited by 68 publications

References 4 publications

From unstable CsSnI3 to air-stable Cs2SnI6: A lead-free perovskite solar cell light absorber with bandgap of 1.48 eV and high absorption coefficient

From unstable CsSnI3 to air-stable Cs2SnI6: A lead-free perovskite solar cell light absorber with bandgap of 1.48 eV and high absorption coefficient

Optical-Vibrational Properties of the Cs₂SnX₆(X = Cl, Br, I) Defect Perovskites and Hole-Transport Efficiency in Dye-Sensitized Solar Cells

Simultaneous Interfacial Modification and Crystallization Control by Biguanide Hydrochloride for Stable Perovskite Solar Cells with PCE of 24.4%

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Vibrational frequencies and intramolecular forces in anionic tin-halogen complexes and related species

Cited by 68 publications

References 4 publications

From unstable CsSnI3 to air-stable Cs2SnI6: A lead-free perovskite solar cell light absorber with bandgap of 1.48 eV and high absorption coefficient

From unstable CsSnI3 to air-stable Cs2SnI6: A lead-free perovskite solar cell light absorber with bandgap of 1.48 eV and high absorption coefficient

Optical-Vibrational Properties of the Cs2SnX6(X = Cl, Br, I) Defect Perovskites and Hole-Transport Efficiency in Dye-Sensitized Solar Cells

Simultaneous Interfacial Modification and Crystallization Control by Biguanide Hydrochloride for Stable Perovskite Solar Cells with PCE of 24.4%

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Optical-Vibrational Properties of the Cs₂SnX₆(X = Cl, Br, I) Defect Perovskites and Hole-Transport Efficiency in Dye-Sensitized Solar Cells