Halogenated Perovskites for electronics.

Bien que très prometteuses, les cellules solaires de 3ème génération à base de Pérovskites Halogénées souffrent d'une durée de vie trop faible, en raison d'une forte instabilité du matériau Pérovskite vis-à-vis de l'humidité dans l'air. Depuis 10 ans, de nombreuses recherches ont permis d'améliorer considérablement la durée de vie de ces cellules, en partie grâce à l'ingénierie du matériau Pérovskite. C'est dans ce contexte que se situent les résultats de cette thèse. Dans ce manuscrit, est reportée la découverte de la nouvelle famille des Pérovskites Halogénées déficientes en Plomb (ou Étain) et en Iode (ou Brome), abrégée d-PHs. Les d-PHs, en particulier les Iodoplombates, présentent une structure Pérovskite 3D allégée en Plomb, et tolèrent l'incorporation de cations qui outrepassent la limitation imposée par le facteur de Goldschmidt. Les d-PHs Iodoplombates montrent des propriétés optoélectroniques adaptées pour une application en cellules solaires. De plus, ces d- PHs sont plus stables à l'air libre, vis-à-vis de l'humidité. De manière remarquable, certaines de ces d-PHs montrent une stabilité plus de dix fois supérieure à celle de leurs homologues Pérovskites non déficientes. Cette famille d-PHs ouvre une nouvelle voie pour la chimie des Pérovskites Halogénées de structure 3D, et offre aussi la possibilité d'allier performance et stabilité pour les cellules solaires Pérovskites.Although the Halogenated Perovskites based 3rd generation of solar cells are very promising, they suffer from a too short lifetime, which is due to a high instability of the Perovskite material towards the moisture in air. Since 10 years, many studies have considerably improved the lifespan of these solar cells, thanks in part to the engineering of the Perovskite material. That is in this context that the results of this thesis are located. Here, in this manuscript, the discovery of the new family of lead (or Tin) and Iodide (or Bromide) deficient Halogenated Perovskites is reported (abbreviated d-PHs). The d-PHs, particularly the Iodoplumbates d-PHs, present a lead lightened 3D Perovskite structure, and tolerate the incorporation of cations that don't respect the imposed limitation from the Goldschmidt factor. The Iodoplumbates d-PHs show suitable optoelectronic properties for an application in solar cells. Moreover, this d-PHs are more stable in open air, towards moisture. Remarkably, some of these d-PHs show a stability more than ten times higher than the stability of their non-deficient Perovskite counterparts. This d-PHs family opens up a new path for the chemistry of the 3D-structure Halogenated Perovskites, and also offers the possibility to combine efficiency and stability for Perovskites solar cells

Pérovskites Halogénées pour l'électronique

Although the Halogenated Perovskites based 3rd generation of solar cells are very promising, they suffer from a too short lifetime, which is due to a high instability of the Perovskite material towards the moisture in air. Since 10 years, many studies have considerably improved the lifespan of these solar cells, thanks in part to the engineering of the Perovskite material. That is in this context that the results of this thesis are located. Here, in this manuscript, the discovery of the new family of lead (or Tin) and Iodide (or Bromide) deficient Halogenated Perovskites is reported (abbreviated d-PHs). The d-PHs, particularly the Iodoplumbates d-PHs, present a lead lightened 3D Perovskite structure, and tolerate the incorporation of cations that don't respect the imposed limitation from the Goldschmidt factor. The Iodoplumbates d-PHs show suitable optoelectronic properties for an application in solar cells. Moreover, this d-PHs are more stable in open air, towards moisture. Remarkably, some of these d-PHs show a stability more than ten times higher than the stability of their non-deficient Perovskite counterparts. This d-PHs family opens up a new path for the chemistry of the 3D-structure Halogenated Perovskites, and also offers the possibility to combine efficiency and stability for Perovskites solar cells.Bien que très prometteuses, les cellules solaires de 3ème génération à base de Pérovskites Halogénées souffrent d'une durée de vie trop faible, en raison d'une forte instabilité du matériau Pérovskite vis-à-vis de l'humidité dans l'air. Depuis 10 ans, de nombreuses recherches ont permis d'améliorer considérablement la durée de vie de ces cellules, en partie grâce à l'ingénierie du matériau Pérovskite. C'est dans ce contexte que se situent les résultats de cette thèse. Dans ce manuscrit, est reportée la découverte de la nouvelle famille des Pérovskites Halogénées déficientes en Plomb (ou Étain) et en Iode (ou Brome), abrégée d-PHs. Les d-PHs, en particulier les Iodoplombates, présentent une structure Pérovskite 3D allégée en Plomb, et tolèrent l'incorporation de cations qui outrepassent la limitation imposée par le facteur de Goldschmidt. Les d-PHs Iodoplombates montrent des propriétés optoélectroniques adaptées pour une application en cellules solaires. De plus, ces d- PHs sont plus stables à l'air libre, vis-à-vis de l'humidité. De manière remarquable, certaines de ces d-PHs montrent une stabilité plus de dix fois supérieure à celle de leurs homologues Pérovskites non déficientes. Cette famille d-PHs ouvre une nouvelle voie pour la chimie des Pérovskites Halogénées de structure 3D, et offre aussi la possibilité d'allier performance et stabilité pour les cellules solaires Pérovskites

In low transpiring conditions, uncoupling the BnNrt2.1 and BnNrt1.1 NO3 transporters by glutamate treatment reveals the essential role of BnNRT2.1 for nitrate uptake and the nitrate-signaling cascade during growth

International audienceIn plants, the nitrate transporters, NRT1.1 and NRT2.1, are mainly responsible for nitrate uptake. Intriguingly, both nitrate transporters are located in a complementary manner in different cells layers of the mature root suggesting that their coordination should occur during nitrate uptake and plant growth. This hypothesis was examined on 5-d-old rape seedlings grown on agar medium supplemented with 1 or 5mM nitrate. Seedlings were treated with increasing potassium glutamate concentrations in order to uncouple the two nitrate transporters by inhibiting BnNRT2.1 expression and activity specifically. In both nitrate treatments, increasing the glutamate concentrations from 0.5 to 10mM induced a reduction in 15NO3- uptake and an inhibition of N assimilation. The decrease in 15NO3- uptake was caused by downregulation of BnNRT2.1 expression but surprisingly it was not compensated by the upregulation of BnNRT1.1. This created an unprecedented physiological situation where the effects of the nitrate signal on shoot growth were solely modulated by nitrate absorption. In these conditions, the osmotic water flow for volumetric shoot growth was mainly dependent on active nitrate transport and nitrate signaling. This behavior was confirmed by the allometric relationships found between changes in the root length with 15N and water accumulation in the shoot. These findings demonstrate that the BnNRT2.1 transporter is essential for nitrate uptake and growth, and renew the question of the respective roles of the NRT2.1 and NRT1.1 transporters in nitrate uptake and sensing at the whole plant level

Lead- and Iodide-Deficient (CH 3 NH 3 )PbI 3 ( d -MAPI): The Bridge between 2D and 3D Hybrid Perovskites

International audience3D and 2D hybrid perovskites, which have been known for more than 20 years, have emerged recently as promising materials for optoelectronic applications, particularly the 3D compound (CH3NH3)PbI3 (MAPI). The discovery of a new family of hybrid perovskites called d-MAPI is reported: the association of PbI2 with both methyl ammonium (MA+) and hydroxyethyl ammonium (HEA+) cations leads to a series of five compounds with general formulation (MA)1−2.48x(HEA)3.48x[Pb1−xI3−x]. These materials, which are lead- and iodide-deficient compared to MAPI while retaining 3D architecture, can be considered as a bridge between the 2D and 3D materials. Moreover, they can be prepared as crystallized thin films by spin-coating. These new 3D materials appear very promising for optoelectronic applications, not only because of their reduced lead content, but also in account of the large flexibility of their chemical composition through potential substitutions of MA+, HEA+, Pb2+ and I− ions

In low transpiring conditions, nitrate and water fluxes for growth of [i]B. napus[/i] plantlets correlate with changes in BnNrt2.1 and BnNrt1.1 nitrate transporter expression

International audienceWe analyzed how changes in BnNrt nitrate transporter gene expression induced by nitrate are associated with morphological changes in plantlets and osmotic water flow for growth. We hypothesized that in a Petri dish system, reduction in transpiration should induce conditions where nitrate and water fluxes for growth depend directly on nitrate transporter activity and nitrate signaling. Rape seedlings growing on agar plates were supplied with increasing external K15NO3 concentrations from 0.05 to 20 mM. After 5 d of treatment, morphological switches in plantlet growth were observed between 0.5 and 5 mM nitrate supply. Root elongation was reduced by 50% while the cotyledon surface area was doubled. These morphological switches were strongly associated with increases in 15NO3- and water uptake rates as well as 15N and water allocation to the shoot. These switches were also highly correlated with the upregulation of BnNrt1.1 and BnNrt2.1 in the root. However, while root expression of BnNrt2.1 was correlated linearly with a shoot growth-associated increase in 15N and water uptake, BnNrt1.1 expression was correlated exponentially with both 15N and water accumulation. In low transpiring conditions, the tight control exercised by nitrate transporters on K15NO3 uptake and allocation clearly demonstrates that they modulated the nitrate-signaling cascade involved in cell growth and as a consequence, water uptake and allocation to the growing organs. Deciphering this signaling cascade in relation to acid growth theory seems to be the most important challenge for our understanding of the nitrate-signaling role in plant growth

Ethylene modifies architecture of root system in response to stomatal opening and water allocation changes between root and shoot

Ethylene plays a key role in the elongation of exploratory and root hair systems in plants, as demonstrated by pharmacological modulation of the activity of ethylene biosynthesis enzymes: ACC synthase (ACS) and ACC oxidase (ACO). Thus, treatments with high concentrations (10 µM) of aminoethoxyvinylglycine (AVG, inhibitor of ACS) and 1-aminocyclopropane carboxylic acid (ACC, ethylene precursor, ACO activator) severely decrease the elongation of the exploratory root system but induce opposite effects on the root hair system: root hair length and numbers were increased in seedlings treated with ACC, whereas they were reduced in seedlings treated with AVG. Until now, such elongation changes of root architecture had not been questioned in terms of nitrate uptake. In the march issue of Plant Physiology we report that N uptake and nitrate transporter BnNrt2.1 transcript level were markedly reduced in ACC treated seedlings, but were increased in AVG treated seedlings compared to the control.1 Because recent studies have revealed that ethylene can also modulate stomatal opening as well as root hair cell elongation, we have examined whether pharmacological modulation of ethylene biosynthesis could affect, in an integrated manner, and at a whole-plant level, the exploratory and root hair systems, through changes of stomatal conductance and water allocation between the root and shoot

Elongation Changes of Exploratory and Root Hair Systems Induced by Aminocyclopropane Carboxylic Acid and Aminoethoxyvinylglycine Affect Nitrate Uptake and BnNrt2.1 and BnNrt1.1 Transporter Gene Expression in Oilseed Rape[W]

Ethylene is a plant hormone that plays a major role in the elongation of both exploratory and root hair systems. Here, we demonstrate in Brassica napus seedlings that treatments with the ethylene precursor, aminocyclopropane carboxylic acid (ACC) and the ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG), cause modification of the dynamic processes of primary root and root hair elongation in a dose-dependent way. Moreover, restoration of root elongation in AVG-treated seedlings by 1 mm l-glutamate suggested that high concentrations of AVG affect root elongation through nonoverlapping ethylene metabolic pathway involving pyridoxal 5′-P-dependent enzymes of nitrate (N) metabolism. In this respect, treatments with high concentrations of ACC and AVG (10 μm) over 5 d revealed significant differences in relationships between root growth architecture and N uptake capacities. Indeed, if these treatments decreased severely the elongation of the exploratory root system (primary root and lateral roots) they had opposing effects on the root hair system. Although ACC increased the length and number of root hairs, the rate of N uptake and the transcript level of the N transporter BnNrt2.1 were markedly reduced. In contrast, the decrease in root hair length and number in AVG-treated seedlings was overcompensated by an increase of N uptake and BnNrt2.1 gene expression. These root architectural changes demonstrated that BnNrt2.1 expression levels were more correlated to the changes of the exploratory root system than the changes of the root hair system. The difference between treatments in N transporters BnNrt1.1 and BnNrt2.1 gene expression is discussed with regard to presumed transport functions of BnNrt1.1 in relation to root elongation

Elongation Changes of Exploratory and Root Hair Systems Induced by Aminocyclopropane Carboxylic Acid and Aminoethoxyvinylglycine Affect Nitrate Uptake and BnNrt2.1 and BnNrt1.1 Transporter Gene Expression in Oilseed Rape

International audienceEthylene is a plant hormone that plays a major role in the elongation of both exploratory and root hair systems. Here, we demonstrate in Brassica napus seedlings that treatments with the ethylene precursor, aminocyclopropane carboxylic acid (ACC) and the ethylene biosynthesis inhibitor, aminoethoxyvinylglycine (AVG), cause modification of the dynamic processes of primary root and root hair elongation in a dose-dependent way. Moreover, restoration of root elongation in AVG-treated seedlings by 1 mM L-glutamate suggested that high concentrations of AVG affect root elongation through nonoverlapping ethylene metabolic pathway involving pyridoxal 5#-P-dependent enzymes of nitrate (N) metabolism. In this respect, treatments with high concentrations of ACC and AVG (10 mM) over 5 d revealed significant differences in relationships between root growth architecture and N uptake capacities. Indeed, if these treatments decreased severely the elongation of the exploratory root system (primary root and lateral roots) they had opposing effects on the root hair system. Although ACC increased the length and number of root hairs, the rate of N uptake and the transcript level of the N transporter BnNrt2.1 were markedly reduced. In contrast, the decrease in root hair length and number in AVG-treated seedlings was overcompensated by an increase of N uptake and BnNrt2.1 gene expression. These root architectural changes demonstrated that BnNrt2.1 expression levels were more correlated to the changes of the exploratory root system than the changes of the root hair system. The difference between treatments in N transporters BnNrt1.1 and BnNrt2.1 gene expression is discussed with regard to presumed transport functions of BnNrt1.1 in relation to root elongation

Enhanced Stability and Bangap Tuning of α-[HC(NH2)2]PbI3 Hybrid Perovskite by Large Cation Integration

Computational investigations were conducted thanks to HPC resources provided by [TGCC/CINES/IDRIS] under the allocation 2018-A0010907682 made by GENCIInternational audienceWe report room-temperature synthesis of lead- and iodide-deficient α-[HC(NH)]PbI perovskites (abbreviated d-α-FAPI, FA = formamidinium), with the general formula (A',FA)[PbI] (with A' = hydroxyethylammonium (HEA) or thioethylammonium (TEA) cations, 0.04 ≤ x ≤ 0.15). These materials retain a 3D character of their perovskite network despite incorporation of large HEA or TEA cations, demonstrating that the Goldschmidt tolerance factor can be bypassed. We found that thin films of (TEA,FA)[PbI] ( x = 0.04 and 0.13) show exceptional α-phase stability under ambient conditions, 1 order of magnitude higher than α-FAPI and α-(Cs,FA)PbI thin films. d-α-FAPI phases are shown to maintain a direct band gap, which increases monotonously for x ranging from 0 up to 0.20, with characteristics of a p-type semiconductor for low concentrations of vacancies ( x ≤ 0.13) and n-type for larger ones. They offer alternatives to reach the methylammonium- and bromine-free stable α-FAPI-type phase and open new avenues in the field of perovskite solar cells, up to band gap tuning desirable for tandem solar cells

Synthesis and Characterization of (FA)₃(HEA)₂Pb₃I₁₁: A Rare Example of <1 1 0>-Oriented Multilayered Halide Perovskites

For DFT calculations, this work was granted access to the HPC resources of TGCC/CINES/IDRIS under the allocation 2020-A0090907682 made by GENCIInternational audienceMetal-halide perovskites have recently demonstrated great potential for a wide variety of optoelectronic applications, with their layered subfamily offering improved stability as compared to their 3D analogs. Among the layered compounds, subclass of terminated compounds are currently dominating the field, while subclass is comparably much less explored. Here we report on the synthesis of (FA) 3 (HEA) 2 Pb 3 I 11 obtained by room-temperature liquid-gas diffusion involving the intermediate-size cation hydroxyethylammonium (HEA +), formamidinium (FA +) and PbI 2 dissolved in an acidic solution. This multilayered hybrid perovskite is a rare example of a m= 3 member of the -oriented series (A') 2 (A) m B m X 3m+2. Structural characterization based on X-ray diffraction and NMR investigations reveals that the small size cation FA + is located both in the inner layer of the perovskite sheet, but also in the interlayer space, while the intermediate-size cation HEA + is situated in the outer cavities of the perovskite sheet. (FA) 3 (HEA) 2 Pb 3 I 11 exhibits a broad absorption band in the visible region (400-650 nm) leading to an optical band gap of 1.96 eV. Electronic structure calculations confirm the direct nature of the band gap and evidence sizeable inter layer electronic coupling related to short I…I distances. These features are reminiscent of those observed for -oriented Pb 3 I 10 analogs that have shown photovoltaic efficiencies over 18%. These findings should prompt further investigations for the design of other -oriented multilayered (m= 3, 4,…) metal halide perovskites