Three- and low-dimensional inorganic semiconductors

Papavassiliou, George C.

doi:10.1016/s0079-6786(97)80886-2

Cited by 319 publications

(285 citation statements)

References 760 publications

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“…Organic-inorganic hybrid semiconductors arose in the 90's as unconventional semiconductors with promising optical and electronic properties [1]. In a very general sense, they consist of an inorganic frame, which is the active (i.e., semiconducting) part, and of an organic part which is assumed to be passive and to hinder charge transport.…”

Section: Introductionmentioning

confidence: 99%

Breathing bands due to molecular order in CH3NH3PbI3

Wierzbowska

Meléndez

Varsano

2018

Computational Materials Science

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CH 3 NH 3 PbI 3 perovskite is nowadays amongst the most promising photovoltaic materials for energy conversion. We have studied by ab-initio calculations, using several levels of approximation -namely density functional theory including spin-orbit coupling and quasi-particle corrections by means of the GW method, as well as pseudopotential self-interaction corrections-, the role of the methylammonium orientation on the electronic structure of this perovskite. We have considered many molecular arrangements within 2 × 2 × 2 supercells, showing that the relative orientation of the organic molecules is responsible for a huge band gap variation up to 2 eV. The band gap sizes are related to distortions of the PbI 3 cage, which are in turn due to electrostatic interactions between this inorganic frame and the molecules. The strong dependence of the band gap on the mutual molecular orientation is confirmed at all levels of approximations.Our results suggest then that the coupling between the molecular motion and the interactions of the molecules with the inorganic cage could help to explain the widening of the absorption spectrum of CH 3 NH 3 PbI 3 perovskite, consistent with the observed white spectrum.

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Section: Introductionmentioning

confidence: 99%

Breathing bands due to molecular order in CH3NH3PbI3

Wierzbowska

Meléndez

Varsano

2018

Computational Materials Science

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“…Of the various types of perovskites and morphologies reported to date, CH 3 NH 3 PbI 3 deposited on a mesoporous film of titanium dioxide through a sequential deposition method appears to yield the best certified conversion efficiency 1 . The optical and electronic properties of perovskite materials have been studied thoroughly in recent decades [8][9][10][11] . As hybrid organic-inorganic lead halide perovskites can cumulate functions of light absorption, n-type conduction 6 and p-type conduction 12 , the current picture for the hybrid spiro-OMeTAD|perovskite|TiO 2 cell could be described as follows (Fig.…”

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confidence: 99%

Unravelling the mechanism of photoinduced charge transfer processes in lead iodide perovskite solar cells

et al. 2014

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Lead halide perovskites have recently been used as light absorbers in hybrid organic-inorganic solid-state solar cells, with efficiencies as high as 15% and open-circuit voltages of 1 V. However, a detailed explanation of the mechanisms of operation within this photovoltaic system is still lacking. Here, we investigate the photoinduced charge transfer processes at the surface of the perovskite using time-resolved techniques. Transient laser spectroscopy and microwave photoconductivity measurements were applied to TiO 2 and Al 2 O 3 mesoporous films impregnated with CH 3 NH 3 PbI 3 perovskite and the organic hole-transporting material spiro-OMeTAD. We show that primary charge separation occurs at both junctions, with TiO 2 and the hole-transporting material, simultaneously, with ultrafast electron and hole injection taking place from the photoexcited perovskite over similar timescales. Charge recombination is shown to be significantly slower on TiO 2 than on Al 2 O 3 films.

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“…The shape of these particles, coming from the q-2D parents, is expected to be different from that of particles coming from the corresponding 3D ones, because of the differences in the structure of q-2D and 3D systems (see for example refs. [1,5,6]). In the cases of the compounds rich in iodine as well as the tin analogs, the results are qualitatively the same, but some additional bands are observed, because of the decomposition of the compounds in air [6] and/or the formation of mixed-valent hybrids [12a].…”

Section: Optical Behavior and Discussionmentioning

confidence: 99%

“…[1,5,6]). In the cases of the compounds rich in iodine as well as the tin analogs, the results are qualitatively the same, but some additional bands are observed, because of the decomposition of the compounds in air [6] and/or the formation of mixed-valent hybrids [12a]. The tunability of PL and OA bands in the organic-inorganic hybrid systems described herein is similar to that observed for inorganic semiconductor quantum dots, such as small particles of CdSe x S 1−x or Zn x Cd 1−x S (see refs.…”

Section: Optical Behavior and Discussionmentioning

confidence: 99%

“…The tunability of PL and OA bands in the organic-inorganic hybrid systems described herein is similar to that observed for inorganic semiconductor quantum dots, such as small particles of CdSe x S 1−x or Zn x Cd 1−x S (see refs. [6,16,17] Addendum: Another possible interpretation of the PL enhancement of these (composite) metal halides after grinding is based on the Foerster (or fluorescence) resonant energy transfer [19] in which particles obtained from M n X 3n+1 (IS) act as donors and particles obtaind from M n X 3n+4 (IS) or MX 3 (IS) as acceptors.…”

Section: Optical Behavior and Discussionmentioning

confidence: 99%

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Organic-Inorganic Hybrid Compounds Based on Lead Halide Units: Preparation from Melts and through Grinding Effects

Papavassiliou

Mousdis

Anyfantis

2010

Zeitschrift Für Naturforschung B

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Organic-inorganic hybrid compounds based on lead halide units of the formula (CH 3 NH 3 ) 2 -(CH 3 C 6 H 4 CH 2 NH 3 ) 2 Pb 3 (Br x Y 1−x ) 10 (Y = Cl, I) were prepared from melts, and their optical absorption as well as photoluminescence spectra, before and after grinding the compounds, were investigated. The luminescence of the materials after grinding is strong and is observed with naked eye. By changing the mole fraction (x), the strong photoluminescence in the range from ca. 400 nm to ca. 600 nm could be tuned. These effects indicate that the hybrid compounds are promising materials for potential applications.

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Three- and low-dimensional inorganic semiconductors

Cited by 319 publications

References 760 publications

Breathing bands due to molecular order in CH3NH3PbI3

Breathing bands due to molecular order in CH3NH3PbI3

Unravelling the mechanism of photoinduced charge transfer processes in lead iodide perovskite solar cells

Organic-Inorganic Hybrid Compounds Based on Lead Halide Units: Preparation from Melts and through Grinding Effects

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