Maria Bernechea

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Verified

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• PhD
• ARAID researcher at Aragon Nanoscience and Materials Institute

Solution-processed inorganic solar cells are a promising low-cost alternative to first-generation solar cells. Solution processing at low temperatures combined with the use of non-toxic and abundant elements can help minimize fabrication costs and facilitate regulatory acceptance. However, at present,there is no material that exhibits all these feat...

In the last decade, solution-processed quantum dot/nanocrystal solar cells have emerged as a very promising technology for third-generation thin-film photovoltaics because of their low cost and high energy-harnessing potential. Quantum dot solar cell architectures developed to date have relied on the use of bulk-like thin films of colloidal quantum...

Graphene is an attractive material for optoelectronics and photodetection applications because it offers a broad spectral bandwidth and fast response times. However, weak light absorption and the absence of a gain mechanism that can generate multiple charge carriers from one incident photon have limited the responsivity of graphene-based photodetec...

Bi2S3 nanocrystals are employed as an n-type, non-toxic, inorganic, solution-processed semiconductor in thin film solar cells. The first solution processed-inorganic p-n junction based on p-type PbS QDs and n-type Bi2S3 nanocrystals with both phases contributing to photo-carrier generation is demonstrated. The reported devices show a power conversi...

Hard carbons are the most extended anode materials for sodium-ion batteries (SIBs); however, they suffer from several limitations such as low stability, poor rate performance and low initial Coulombic efficiency (iCE). Herein, a simple, fast, and low-cost surface treatment at room temperature using short-chain organic molecules: 3-mercaptopropionic...

Hard carbons are the most extended anode materials for sodium-ion batteries (SIBs); however, they suffer from several limitations such as low stability, poor rate performance and low initial coulombic efficiency (iCE).Herein, a simple, fast, and low-cost surface treatment at room temperature using short-chain organic molecules: 3-mercaptopropionic...

The study presents a hybrid hard-carbon/nanocrystalline-Bi 2 S 3 material applicable for negative electrodes in sodium-ion batteries. Through a series of comprehensive analyzes, including electrochemical measurements, operando XRD, ex-situ solid-state NMR, and high-resolution...

Compared to other photovoltaic materials, nanomaterials show unique features due to their novel size- and shape-dependent properties such as bandgap tuning, multiple exciton generation, and modulation of n- or p-type behavior by doping or by modifying the ligands on the surface of the nanocrystals. The best-performing nanocrystal solar cells have b...

The paper puts forward the concept of a double-redox electrochemical capacitor operating in an aqueous electrolyte. The redox activity of sulphur from insoluble Bi 2 S 3 nanocrystals embedded in the negative electrode material (up to 10 wt%) operating in 1 mol L −1 Li 2 SO 4 electrolyte is demonstrated. It is also shown that the performance is sign...

In this article, we offer an analysis of point-source water pollution governance in the European agri-food sector. Specifically, we tackle the case study of the wine industry in Aragon (Spain) through the lenses of the networks of action situations approach. We unveil key strategic decisions of wine producers in relation to compliance with water di...

Electrochemical capacitors are attractive power sources, especially when they are able to operate at high frequency (high current regime). In order to meet this requirement their constituents should be made of high conductivity materials with a suitable porosity. In this study, enhanced power and simultaneously high capacitance (120 F g⁻¹ at 1 Hz o...

The development of energy-harvesting and energy-storage devices based on renewable sources will be fundamental for the deployment of autonomous or isolated systems like emerging internet-of-things (IoT) applications. This chapter will focus on the use of bismuth nanomaterials in energy-related applications. These materials fulfill the requirements...

Thin NiOx layers were prepared by oxidation at 400, 500 and 600 °C of metallic Ni deposited by electron beam evaporation. The bandgap of NiOx determined from optical measurements increases from 3.6 to 3.7 eV with the increase of oxidation temperature from 400 to 500°C. Higher temperature leads to larger grain sizes, 12.6 nm at 400 °C, 15.3 nm at 50...

Semiconductor nanocrystals, used in quantum dot solar cells, are interesting materials for photovoltaics because they can be obtained in solution and can be composed of abundant elements. Moreover, as compared to other photovoltaic materials, nanomaterials show unique features due to their novel size-and shape-dependent properties such as band gap...

Solution‐processed AgBiS2 nanocrystal films are a promising material for non‐toxic, earth‐abundant solar cells. While solar cells with good device efficiency have been demonstrated, so far, hardly anything is known about charge generation, transport, and recombination processes in these films. Here, a photoinduced time‐resolved microwave conductivi...

In this Research Update, we briefly summarize some of the bismuth materials that have been investigated for their use in photovoltaic solar cells. We focus on bismuth-based perovskites and bismuth halides, as alternatives to lead-halide perovskites, and bismuth-based sulfides (Bi2S3, CuxBiySz, and AgBiS2), as alternatives to lead sulfide quantum do...

Recent experiments motivated by solar light harvesting applications have brought a renewed interest in AgBiS2 as an environmentally friendly material with appealing photovoltaic properties. The lack of detailed knowledge on its bulk structural and electronic structure however inhibits further development of this material. Here we have investigated...

The hybridization of two-dimensional transition metal dichalcogenides (TMDCs) with colloidal quantum dots has been demonstrated to be an ideal platform for low dark-current and highly sensitive photodetection due to a carrier recirculation mechanism producing very high gain. However, TMDCs react sensitively to surface modifications and the sensitiz...

We report the synthesis and full characterization of colloidal Bi2S3 nanocrystals with different sizes, showing a band gap variation up to 0.2 eV, and pointing to quantum confinement effects. Polymer-nanocrystal solar cells have been fabricated to study the effect of the size, and band gap change, on the performance of the devices. We have found th...

Low bandgap inorganic semiconductor nanowires have been served as building blocks in solution processed solar cells to improve their power conversion capacity and reduce fabrication cost. In this work, we first reported environmentally friendly bismuth sulfide nanowire arrays grown from colloidal seeds on a transparent conductive substrate via mild...

Metallic nanoparticles tailor the electronic properties of PbS colloidal quantum dots in a post-synthetic, all solution-processable approach. The Fermi level of the resulting nanocomposites can be tuned from p- to n-type due to remote charge transfer and electron trap state passivation. This concurrently reduces dark current, improves time response...

More efficient charge collection and suppressed trap recombination in colloidal quantum dot (CQD) solar cells is achieved by means of a bulk nano-heterojunction (BNH) structure, in which p-type and n-type materials are blended on the nanometer scale. The improved performance of the BNH devices compared to that of bilayer devices is displayed in hig...

In this paper we employ a thiol-functionalized polymer (P3HT-SH) as a leverage to tailor the nanomorphology and electronic coupling in polymer-nanocrystal composites for hybrid solar cells. The presence of the thiol functional group allows for a highly crystalline semiconducting polymer film at low thiol contents and allows for improved nanomorphol...

Impedance Spectroscopy (IS) proves to be a powerful tool for the determination of carrier lifetime and majority carrier mobility in colloidal quantum dot films. We employ IS to determine the carrier lifetime in PbS quantum dot Schottky solar cells with Al and we verify the validity of the technique via transient photovoltage. We also present a simp...

In this work, we study the efficiency of the resonance energy transfer from PbS quantum dots to bulk silicon. We present spectroscopic evidence that resonance energy transfer from PbS quantum dots to bulk silicon can be an efficient process for separation distances below 12 nm. Temperature measurements are also presented for PbS quantum dots deposi...

High efficiency organic and hybrid solar cells create demand for novel electron acceptor materials that possess appropriate energetic band levels and bandgap for efficient solar energy harnessing. We present hybrid bulk heterojunction devices based on P3HT and bismuth sulfide nanocrystals, a semiconductor based on environmentally friendly compounds...

In this work, monolayers of dielectric spheres are embedded within colloidal PbS-TiO 2 bulk heterojunction solar cells to improve the light absorption of the quantum dots in the near infrared region. The optimum location of the sphere monolayer within the heterojunction is investigated in terms of optical absorption and photon to current conversion...

The unique way in which light resonates in microspheres is applied by G. Konstantatos and co-workers on page 139 to enhance the light-harvesting efficiency of a solution-processed PbS quantum dot-TiO2 heterojunction. Depending on the relative position of the silica sphere monolayer with respect to the PbS-TiO2 bilayer, different resonant modes can...

In this work, we investigate the temperature dependence of the photoluminescence decay and integrated photoluminescence of oleic acid capped PbS quantum dots with diameters ranging from 2.3 to 3.5 nm over a broad temperature range (6−290 K). All the investigated samples exhibit similar behavior, consisting of three different temperature regimes. Th...

Plasmonic light trapping can increase the absorption of light in thin semiconductor films. We investigate the effect of embedded metal nanoparticle (MNP) arrays on the electrical characteristics of ultra-thin PbS colloidal quantum dot (CQD) photoconductors. We demonstrate that direct contact with the metal nanoparticles can suppress or enhance the...

Semiconductor Quantum Dots (QDs) are promising materials for photovoltaic applications because they can be engineered to absorb light from visible to near infrared and single absorbed photons can generate multiple excitons. However, these materials suffer from low carrier mobility, which severely limits the prospects of efficient charge extraction...

We report broadband responsivity enhancement in PbS colloidal quantum dot (CQDs) photoconductive photodetectors due to absorption increase offered by a plasmonic scattering layer of Ag metal nanoparticles. Responsivity enhancements are observed in the near infrared with a maximum 2.4-fold increase near the absorption band edge of ∼1 μm for ∼400 nm...

Bi2S3 nanocrystals are employed in a polymer/nanocrystal solar cell as a non-toxic inorganic electron acceptor with a high absorption coefficient and a bandgap of 1.3 eV optimal for single-junction solar harnessing. The reported solar cell yields a power conversion efficiency of 0.46% in a bilayer structure and shows an internal quantum efficiency...

Reaction of [RuCl2(PPh3)(3)] with excess of PPh2C CFc (Fc = ferrocenyl) proceeds with formation of [trans-RuCl2(PPh2C CFc)(4)] (3), which reacts with HC CR (R = Ph, Tol) via dissociative loss of one PPh2C CFc ligand to yield vinylidene complexes [mer,cis-RuCl2(C=CHR)(PPh2C 7CFc)(3)] (R = Ph 4a, Tol 4b). Reported herein also is the preparation of a...

The synthesis of PtRu nanoparticles has been accomplished by using the dendrimer-encapsulated nanoparticle (DEN) approach. We report that the surface distribution of the particles can be tuned by suitable control of the reaction pathway. The present study focuses on the synthesis and characterization of Pt and PtRu nanoparticles and the evaluation...

The synthesis of PtRu nanoparticles has been accomplished by using the dendrimer-encapsulated nanoparticle (DEN) approach. We report that the surface distribution of the particles can be tuned by suitable control of the reaction pathway. The present study focuses on the synthesis and characterization of Pt and PtRu nanoparticles and the evaluation...

The behavior of the cationic alkynylphosphine complex [Rh(η 5 -Cp*)Cl(PPh 2 CtCPh) 2 ](CF 3 SO 3) (1) under thermal or basic conditions is described. Complex 1 rearranges thermally (toluene, reflux) to generate a solution from which a mixture formed by 1, the monohydroalkylated derivative [Rh{κP:η 5 -C 5 Me 4 -(CH 2 CPhdCHPPh 2)}Cl(PPh 2 CtCPh)](CF...

The study of the reaction between the ethylene [Pt(eta-H2C = CH2)(PPh3)2] or alkyne [Pt(eta2-HC [triple bond] CR)(PPh3)2] (R = SiMe3 1, Bu(t) 2) complexes with [cis-Pt(C6F5)2(thf)2] (thf = tetrahydrofuran) has enabled us to observe the existence of competitive processes between the activation of a P-C(Ph) bond on the PPh3 ligand, to give the binucl...

A new series of functionalized (µ-hydride)(µ-acetylide) isomeric derivatives [trans-(PPh 3)(C 6 F 5)Pt(µ-H)(µ-1κC R :η 2 -CtCR)Pt(C 6 F 5)(PPh 3)] (3) and [cis,cis-(PPh 3) 2 Pt(µ-H)(µ-1κC R :η 2 -CtCR)Pt(C 6 F 5) 2 ] (4) (R) (4-CH 3)C 6 H 4 , a; (4-CN)C 6 H 4 , b; CMedCH 2 , c; C(OH)Me 2 , d; C(OH)EtMe, e; C(OH)Ph 2 , f) have been prepared by react...

Six-coordinate [trans-RuCl 2 (PPh 2 CtCR) 4 ] (R) Ph (1), (4-CH 3)C 6 H 4 (2), (4-OCH 3)C 6 H 4 , (3), (4-CF 3)C 6 H 4 (4)) were obtained from the reaction of RuCl 3 ‚xH 2 O with the appropriate alkynylphosphine (PPh 2 CtCR) in ethanol. An X-ray crystal structure analysis of 1‚4H 2 O reveals that the complex is obtained as the trans isomer, with th...

The µ-hydride µ-acetylide [cis,cis-(PPh 3) 2 Pt(µ-H)(µ-1κC R :η 2 -CtCPh)Pt(C 6 F 5) 2 ] (1b) and the µ-vinylidene [cis,cis-(CO)(C 6 F 5) 2 Pt(µ-CdCHPh)Pt(PPh 3) 2 ] (2) have been prepared by reaction of the η 2 -phenylacetylene Pt(0) complex [Pt(η 2 -HCtCPh)(PPh 3) 2 ] as the starting material with the disolvated [cis-PtR 2 S 2 ] and the monosolva...

The synthesis and characterization of a series of mononuclear d8 complexes with at least two P-coordinated alkynylphosphine ligands and their reactivity toward cis-[Pt(C6F5)2(THF) 2] are reported. The cationic [Pt(C6F5)- (PPh2C=CPh)3](CF3SO3), 1, [M(COD)(PPh2C=CPh)2](CIO4) (M = Rh, 2, and Ir, 3), and neutral [Pt(o-C6H4E2)-(PPh 2C=CPh)2] (E = O, 6,...

The neutral complexes [(η6-p-cymene)RuCl2(PPh2CCR)] (R = Ph 1, tBu 2, (4-CH3)C6H4 3, (4-CCPh)C6H4 4, (4-CN)C6H4 5) have been synthesized by reacting [(p-cymene)RuCl2]2 with the respective alkynylphosphine. Treatment of 1−5 with AgOTf or TlPF6 and the corresponding PPh2CCR allows the preparation of cationic bis(diphenylphosphino) compounds [(η6-p-cy...

The novel P-coordinated diphenyl(phenylethynyl)phosphine complexes [Cp*MCl2(PPh2CCPh)] [M = Rh 1, Ir 2] have been prepared by the bridge splitting of [Cp*MCl2]2 with PPh2CCPh. Treatment of 1 and 2 with AgTfO and PPh2CCPh affords the corresponding cationic compounds [Cp*MCl(PPh2CCPh)2](OTf) [M = Rh 3, Ir 4, OTf = triflate], respectively. The analogo...