Ricardo Izquierdo

École de Technologie Supérieure · Département de génie électrique

The PDI-EH molecule was synthesized and integrated into ternary OSCs to obtain miscibility-driven morphology optimization. The relationship between the optimized morphology and charge carrier dynamics was explored by PiFM and TP-AFM characterization.

We explored nitrofluorene derivatives as tunable electron-withdrawing groups for acceptor-donor-acceptor (A–D–A) type non-fullerene acceptors. Their optoelectronic properties and performance in bulk heterojunction solar cells with PBDB-T donor polymer are reported....

It is highly desired to develop advanced characterization techniques to explore the 3D nanoscale morphology of the complicated blend film of ternary organic solar cells (OSCs). Here, ternary OSCs are constructed by incorporating the nonfullerene acceptor perylenediimide (PDI)-diketopyrrolopyrrole (DPP)-PDI and their morphology is characterized in d...

In this work, we elucidate the photodegradation pathway of A-D-A type nonfullerene acceptors for organic photovoltaics. Using IT-4F as a benchmark example, we isolated the photoproducts and proved them isomers of IT-4F formed via a 6-e electrocyclic reaction between the dicyanomethylene unit and the thiophene ring, followed by a 1,5-sigmatropic hyd...

In this work, we elucidate the photodegradation pathway of A-D-A type nonfullerene acceptors for organic photovoltaics. Using IT-4F as a benchmark example, we isolated the photoproducts and proved them isomers of IT-4F formed via a 6-e electrocyclic reaction between the dicyanomethylene unit and the thiophene ring, followed by a 1,5-sigmatropic hyd...

Alloyed tin-lead (Sn-Pb) perovskite solar cells (PSCs) exhibit broader photoresponse up to 1050 nm; however, their efficiency was inferior to that of Pb analogs. Trap-assisted recombination associated with Sn vacancies formed through Sn2+ oxidation is a major detrimental factor, limiting their efficiency. By incorporating bulkier phenylethylammoniu...

In this work, we elucidate the photodegradation pathway of IT-4F, a benchmark A-D-A type semiconductor for organic photovoltaics. The photoproducts were isolated and shown to be isomers of IT-4F formed via a 6-e electrocyclic reaction between the dicyanomethylene unit and the thiophene ring, followed by a 1,5-sigmatropic hydride shift. Importantly,...

In this work, we elucidate the photodegradation pathway of IT-4F, a benchmark A-D-A type semiconductor for organic photovoltaics. The photoproducts were isolated and shown to be isomers of IT-4F formed via a 6-e electrocyclic reaction between the dicyanomethylene unit and the thiophene ring, followed by a 1,5-sigmatropic hydride shift. Importantly,...

The commercial feasibility of perovskite solar cells (PSCs) is not guaranteed as long as lead (Pb) is present in the active material, halide perovskites. Mixed halide tin (Sn)-based alloyed perovskites with optimal band gaps ranging from 1.15 to 3.55 eV are excellent alternatives to Pb-based perovskites. In this work, we find that the addition of a...

A stable and magnetic graphene oxide (GO) foam-polyethyleneimine-iron nanoparticle (GO-PEI-FeNPs) composite has been fabricated for removal of endocrine disruptors-bisphenol A, progesterone and norethisterone-from aqueous solution. The foam with porous and hierarchical structures was synthesized by reduction of graphene oxide layers coupled with co...

The integration of graphene materials into electrochemical biosensing platforms has gained significant interest in recent years. Bulk quantities of graphene can be synthesized by oxidation of graphite to graphite oxide and subsequent exfoliation to graphene oxide (GO). However, the size of the resultant GO sheets changes from the parent graphite yi...

Binary solvent additive engineering is an effective strategy to optimize the morphology of photoactive film for high‐efficiency organic photovoltaic devices, however, the effect of single component in binary solvent additives system on device performance and the combination principle of binary solvent additives are unclear yet. In this study, we in...

Graphene and graphene oxide (GO) materials have attracted enormous attention in the biosensing field. Here, we report an evaluation of electrochemically reduced graphene oxide (ERGO) of different sheet sizes (0.45–0.7 μm, 0.7–2.5 μm and >300 μm) towards the voltammetric biosensing of vascular endothelial growth factor (VEGF) and the effect of the s...

Headed for developing minimalistic strategies to produce graphene@metal hybrids for electronics on a larger scale, we discovered that graphene oxide (GO)-metal oxide (MO) hybrids are formed spontaneously in water at room temperature in the presence of nothing else than graphene oxide itself and metal ions. Our observations show metal oxide nanopart...

Organic solar cells (OSCs) are regarded as one of the promising photovoltaic technologies to address the issues of energy crisis and environmental pollution all over the world, and are thus considered as the next generation of solar cells. ¹ However, the devices power conversation efficiency and stability of the devices are still important factors...

The facile synthesis of a series of benzodithiophene (BDT)- and indacenodithiophene (IDT)-based A-D-A oligomers with different end groups is reported and their properties studied by optical spectroscopy, electrochemistry and DFT calculations. The permutation of central and terminal units tunes the optoelectronic properties and photovoltaic device c...

High efficiency, excellent stability, and air processability are all important factors to consider in endeavoring to push forward the real‐world application of organic solar cells. Herein, an air‐processed inverted photovoltaic device built upon a low‐bandgap, air‐stable, phenanthridinone‐based ter‐polymer (C150H218N6O6S4)n (PDPPPTD) and [6,6]‐phen...

Three-dimensional (3D) perovskite solar cells are prone to degradation in the presence of moisture, heat, and light. Recently, two-dimensional (2D) perovskites are synthesized by isolating metal halide perovskite layers using aliphatic or aromatic alkylammonium spacer cation, which can retain their performance under ambient humidity levels due to t...

Performance of bulk heterojunction polymer solar cells (PSCs) highly relies on the morphology of the photoactive layer involving conjugated polymers and fullerene derivatives as donors and acceptors, respectively. Herein, butylamine was found to be able to optimize the morphology of the donor/acceptor (D/A) film composed of blend of poly(3-hexylthi...

Birds have been used intensively as biomonitors of halogenated flame retardants (HFRs), and several studies have reported elevated tissue concentrations and inter-individual variability for these contaminants. While diet is known to be an important exposure pathway for HFRs in birds, it has been suggested that exposure through air may represent an...

The design and development of inexpensive and highly efficient electrocatalysts for hydrogen production underpin several emerging clean-energy technologies. In this work, we show a novel strategy to synthesize vertical aligned porous MoSe2 by two-step co-electrodeposition/etching method. The morphology of the porous MoSe2 can be easily tuned by mer...

A simple approach to develop a single layer graphene decorated with rhodium nanoparticles (RhNPs) on a flexible polyethylene terephthalate (PET) substrate is presented. The ability to control the distribution and size of the RhNPs on the CVD graphene support upon changing the electrodeposition conditions is demonstrated. The distribution of the RhN...

Printed alkaline batteries based on a zinc anode and a manganese dioxide cathode using two different potassium hydroxide-based electrolytes were prepared. Inks were developed for both electrodes and electrolytes to fabricate the batteries by screen-printing techniques. Potentiodynamic electrochemical measurements allowed us to determine the electro...

The unique optical properties possessed by plasmonic noble metal nanostructures in consequence of localized surface plasmon resonance (LSPR) are useful in diverse applications like photovoltaics, sensing, non-linear optics, hydrogen generation, and photocatalytic pollutant degradation. The incorporation of plasmonic metal nanostructures into solar...

Since the emergence of microfluidic platforms sensors integration has been a major challenge. With the advances in miniaturization of these platforms, there is a need for solutions to integrate various optical components in order to build sensors, which will offer different detection characteristics such as several emission and sensing wavelengths....

Semiconductor nanocrystals that show plasmonic resonance represent an emerging class of highly promising plasmonic materials with potential applications in diverse fields, such as sensing and optical and optoelectronic devices. We report a new approach to synthesizing homogeneous covellite CuS nanoplatelets in air and the almost complete disappeara...

Le transport atmosphérique des retardateurs de flamme halogénés (RFH) est aujourd’hui bien documenté (Csizar et al., 2014; Abassi et al., 2015). D’abord ajoutés à une multitude de produits de consommation pour répondre aux normes de sécurité incendie, les RFH migrent continuellement depuis leurs supports initiaux vers l’atmosphère. Considérant l’ef...

Graphene oxide is regarded as a major precursor for graphene-based materials. The development of graphene oxide derivatives with new functionalities requires a thorough understanding of its chemical reactivity, especially for canonical synthetic methods such as the Diels-Alder cycloaddition. We successfully extended the Diels-Alder reaction to grap...

A one-step in-situ route to free standing core–shell silicon carbide in graphene nanoparticles on monolayer graphene is presented. The core–shell SiC@Graphene nanoparticle growth is realized by a simple chemical vapor deposition (CVD) process where carbon and silica precursors are simultaneously introduced into the growth chamber. This process perm...

This paper reports a microfluidic platform with external hybrid integration of an organic light emitting diode (OLED) as an excitation source. This device can be used as a simple and cost effective biosensing element. The device is capable of rapid in-situ detection of biological elements such as sensing of interaction of antigen with fluorescent t...

Since the emergence of microfluidic platforms, optical sensor integration has been a major challenge. With the advances in miniaturization of these platforms, there is a need of solutions to integrate various optical components in order to build sensors, which will offer different detection characteristics such as several emission and sensing wavel...

Near infrared (NIR) PbS quantum dots (QDs) have attracted significant research interest in solar cell applications as they offer several advantages, such as tunable band gaps, capability of absorbing NIR photons, low cost solution processability and high potential for multiple exciton generation. Nonetheless, reports on solar cells based on NIR PbS...

A portable system to monitor water quality in both developed and developing countries is highly required. Currently, there is no commercial test available to satisfy this demand, as only accredited laboratories can perform such evaluations. Miniaturization of analytical instrumentation is one of the dominant trends within the chemical and biologica...

The development of new nanomaterial like carbon nanotubes, graphene and nanowires brings new possibilities to existing technologies. With the emergence of transparent electrode based on these materials, we could imagine new type of sensors, which combines transparency and flexibility. Silver nanowire transparent electrodes are currently transformin...

All solution processed depleted bulk heterojunction (DBH) solar cell devices based on near infrared (NIR) PbS/CdS core-shell quantum dots (QDs) and films of rutile TiO2 nanorod arrays have been investigated. The device fabrication was achieved through the layer-by-layer spin coating of PbS/CdS QDs, in ambient atmosphere, onto hydrothermally grown T...

The effect of inserting low density of gold nanorods in the metallic rear electrode of polymer solar cells on their performance was studied. Gold nanorods were introduced by spin-coating their aqueous solution directly on top of the poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric-acid-methyl- ester layer. The resulting devices showed a 5%...

We report on a modified bulk heterojunction (BHJ) solar cell in which a nanohybridized composition of lead sulfide (PbS) colloidal quantum dots (QDs) and multiwall carbon nanotubes (MWCNTs) were incorporated into a standard regioregular poly(3–hexylthiophene) (rr–P3HT):phenyl–C61–butyric acid methyl ester (PCBM) blend. This hybrid ((P3HT:PCBM):PbS–...

In this work, the dependence of the enhancement in the efficiency of polymer solar cells incorporated with gold nanorods embedded in the photoactive layer on the photoactive layer thickness has been studied in detail. Synthesized toluene-based gold nanorods were introduced to devices by simply blending them with a solution of poly(3-hexylthiophene-...

In this work, the effect of gold nanorods on the performance of poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric-acid-methyl-ester bulk heterojunction solar cells was investigated. Gold nanorods were introduced into the anodic buffer layer by simply blending them with the solution of poly(3,4-ethyl-enedioxythiophene):poly(styrenesulfonate)....

Different densities of gold nanorods (GNRs) were incorporated on the back electrode of bulk heterojunction organic solar cell (OSC). GNRs layers (1, 3, and 5) were deposited on top of the poly(3-hexylthiophene) (P3HT) and phenyl- C61-butyric acid methyl ester (PCBM) layer using spin-casting technique. According to the optical and structural charact...

An alternative chemical vapor doping (CVDo) method for doping transparent and conductive films of carbon nanotubes (CNTs) is presented. The different effects between the traditional solution doping process and the proposed vapor doping method are compared in detail by means of optical microscopy, SEM, sheet resistance measurements, and Raman and UV...

We report the first miniaturized fluorescent sensor based on algae, with an organic light emitting diode (OLED) and an organic photodetector (OPD) integrated into a microfluidic chip. The blue emission OLED was used as the excitation source, while a blend of PTB3/PC(61)BM was used for the fabrication of the organic photodetector. Excitation and emi...

A solution-processed nanoarchitecture based on PbS quantum dots (QDs) and multi-walled carbon nanotubes (MWCNTs) is synthesized by simply mixing the pre-synthesized high-quality PbS QDs and oleylamine (OLA) pre-functionalized MWCNTs. Pre-functionalization of MWCNTs with OLA is crucial for the attachment of PbS QDs and the coverage of QDs on the sur...

Preliminary work has been conducted in order to investigate the possibility of using transparent electrodes made of single wall carbon nanotubes as cathodes in OLED applications. From the results, efficient electron injection from SWCNTs was achieved by modifying the surface of SWCNTs with a thin layer of Pd/Al/LiF while maintaining transparency. H...

By engineering the interface between the intermediate photoactive layer and the cathode aluminum (Al) electrode, through the introduction of ultra-thin layers of various materials, in a standard bulk heterojunction (BHJ) polymer solar cell (PSC) fabricated of regioregular poly(3-hexylthiophene) (rr-P3HT) and phenyl-C61-butyric acid methyl ester (PC...

The effect of using an anodic layer with low density (~ 6x108 cm-2) of gold nanorods (GNR) in organic bulk heterojunction poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) solar cells was studied. GNRs were deposited using several techniques, which produced various densities of GNRs on the anode layer. The anodic layers...

We report the first disposable fluorescent biosensor based on algae, with an organic light emitting diode and an organic photodetector (OPD) miniaturized into a microfluidic chip. A DPVBi OLED was used as the excitation source, while a blend of PTB3/PCBM was used for the organic photodetector. The fluorescence biosensor is integrated in a microflui...

Top emission organic light emitting diodes (OLEDs) with carbon nanotubes (CNTs) as top electrodes were fabricated and characterized. Devices were fabricated on glass substrates with evaporated bottom Al/LiF cathodes, a spin coated organic emissive layer and a PEDOT-PSS hole injection layer. Transparent thin CNT films were deposited on top of the em...

Two type of devices suited for lab-on-a-chip applications were investigated. First, the integration of a polymeric microactuator deposited on top of carbon electrodes placed below a microfluidic channel. This actuator uses the out-of-plane strain of the polypyrrole/NaDBS (sodium dodecylbenzene sulfonate) system. The electrodeposition of polypyrrole...

This paper describes a fluorescence biosensor based on a microfluidic device where an organic LED is used as light emitting source. The device was able to detect fluorescence from a 0.012 μl volume chamber containing 3 ng of donkey anti-sheep IgG (Immunoglobulin G) conjugates tagged with Alexafluor 488 fluorophores. The minimum detectable concentra...

Thin films of a Na SuperIonic CONductor, NASICON, were deposited for the first time by pulsed laser deposition (PLD). The influence of the various deposition parameters on film quality was studied. NASICON films were characterized both physico-chemically and electrically. The use of NASICON thin films for the fabrication of gas sensors and selectiv...

Pulsed laser deposition is used to deposit thin films of Na superionic conductor (NASICON). The resulting thin films are good ionic conductors with resistivities between 3 x 10 3 and 5 x 10 4 Ω cm at room temperature depending on the deposition conditions. By depositing these films on Raipore cation-selective membranes, composite membranes can be f...