Optimised In 2

Indium sulphide has been extensively investigated as a component for different kind of photovoltaic devices (organic-inorganic hybrid devices, all inorganic, dye sensitized cells). In this paper, we have optimised the growth conditions of indium sulphide thin films by means of a low cost, versatile deposition technique, like spray pyrolysis. The quality of the deposited films has been characterised by micro-Raman, vis-UV spectroscopy, and atomic force microscopy. Substrate deposition temperature and different postdeposition annealing conditions have been investigated in order to obtain information about the quality of the obtained compound (which crystalline or amorphous phases are present) and the morphology of the deposited films. We have shown that the deposition temperature influences strongly the amount of amorphous phase and the roughness of the indium sulphide films. Optimised postdeposition annealing treatments can strongly improve the final amount of the beta phase almost independently from the percentage of the amorphous phase present in the as deposited films

Toward Real Setting Applications of Organic and Perovskite Solar Cells: A Comparative Review

The development of efficient, reliable, and clean energy sources is one of the global priorities for enabling a sustainable transition toward a green society and economy. The third‐generation solar cells, such as organic solar cells (OSCs) and perovskite solar cells (PSCs), are among the most promising platforms for the generation of electrical power from sunlight for a wide range of applications. However, the widespread diffusion of emerging photovoltaics technologies is hampered by issues occurring in the translation of laboratory‐scale R&D efforts to real settings. Herein, starting from a thorough survey of latest research on OSC and PSC technologies, critical factors related to fabrication and operation of solar cells, especially in terms of materials properties/requirements and beyond metrics built on efficiency only, are analyzed. On this basis, OSCs and PSCs are compared in terms of their potential in real application scenarios, also highlighting their peculiarities in view of their future large‐scale utilization

Improvement of Dye Solar Cell Efficiency by Photoanode Posttreatment

The basic concept for efficiency improvement in dye-sensitized solar cells (DSSC) is limiting the electron-hole recombination. One way to approach the problem is to improve the photogenerated charge carriers lifetime and consequently reduce their recombination probability. We are reporting on a facile posttreatment of the mesoporous photoanode by using a colloidal solution of TiO2 nanoparticles. We have investigated the outcome of the different sintering temperature of the posttreated photoanodes on their morphology as well as on the conversion efficiency of the DSSC. The DSSCs composed of posttreated photoanodes at 450°C showed an increase in JSC and consequently an increase in efficiency of 10%. Investigations were made to determine the electron recombination via the electrolyte by the OCVD technique. We found that the posttreatment has the effect of reducing the surface trap states and thus increases the electron lifetime, which is responsible for the increase of the overall cell efficiency

Graphene oxide doped polysulfone membrane adsorbers for the removal of organic contaminants from water

This work explored polysulfone (PS) – graphene oxide (GO) based porous membranes (PS-GO) as adsorber of seven selected organic contaminants of emerging concern (EOCs) including pharmaceuticals, personal care products, a dye and a surfactant from water. PS-GO was prepared by phase inversion method starting from a PS and GO mixture (5% w/w of GO). The porous PS-GO membranes showed asymmetric and highly porous micrometer sized pores on membrane top (diameter ≈20 μm) and bottom (diameter ≈2–5 μm) surfaces and tens of microns length finger like pores in the section. Nanomechanical mapping reveals patches of a stiffer material with Young modules comprised in the range 15–25 GPa, not present in PS pure membranes that are compatible with the presence of GO flakes on the membrane surfaces. PS-GO was immersed in EOCs spiked tap water and the adsorbance efficiency at different contact times and pH evaluated by HPLC analysis. Ofloxacin (OFLOX), benzophenone-3 (BP-3), rhodamine b (Rh), diclofenac (DCF) and triton X-100 (TRX) were removed with efficiency higher than 90% after 4 h treatments. Regeneration of PS-GO and reuse possibilities were demonstrated by washing with ethanol. The adsorption efficiencies toward OFLOX, Rh, DCF and carbamazepine (CBZ) were significantly higher than those of pure PS membrane. Moreover, PS-GO outperformed a commercial granular activated carbon (GAC) at low contact times and compared well at longer contact time for OFLOX, Rh, BP-3 and TRX suggesting the suitability of the newly introduced material for drinking water treatment

Core-shell graphene oxide-polymer hollow fibers as water filters with enhanced performance and selectivity

Commercial hollow fiber filters for micro- and ultrafiltration are based on size exclusion and do not allow the removal of small molecules such as antibiotics. Here, we demonstrate that a graphene oxide (GO) layer can be firmly immobilized either inside or outside polyethersulfone-polyvinylpyrrolidone hollow fiber (Versatile PES (R), hereafter PES) modules and that the resulting core-shell fibers inherits the microfiltration ability of the pristine PES fibers and the adsorption selectivity of GO. GO nanosheets were deposited on the fiber surface by filtration of a GO suspension through a PES cartridge (cut-off 0.1-0.2 mu m), then fixed by thermal annealing at 80 degrees C, rendering the GO coating stably fixed and unsoluble. The filtration cut-off, retention selectivity and efficiency of the resulting inner and outer modified hollow fibers (HF-GO) were tested by performing filtration on water and bovine plasma spiked with bovine serum albumin (BSA, 66 kDa, approximate to 15 nm size), monodisperse polystyrene nanoparticles (52 nm and 303 nm sizes), with two quinolonic antibiotics (ciprofloxacin and ofloxacin) and rhodamine B (RhB). These tests showed that the microfiltration capability of PES was retained by HF-GO, and in addition the GO coating can capture the molecular contaminants while letting through BSA and smaller polystyrene nanoparticles. Combined XRD, molecular modelling and adsorption experiments show that the separation mechanism does not rely only on physical size exclusion, but involves intercalation of solute molecules between the GO layers

Multi-modal sensing in spin crossover compounds

We exploited the solvatochromic spin-state switching in a spin crossover (SCO) compound based on the Fe-II complex and the simultaneous change of spectroscopic properties for selective multimodal sensing of methanol and ethanol. We demonstrate that sensing capabilities are due to the inclusion of methanol or ethanol molecules into the crystalline structure, which tailors simultaneously the transition temperature, colour, birefringence and vibrational modes. We exploited this capability by integrating a neutral compound, switchable at room temperature, into a micrometric TAG sensitive to the colour and birefringence. The system was characterised by optical microscopy, magnetic susceptibility, Raman spectroscopy and X-ray diffraction

Core–shell graphene oxide–polymer hollow fibers as water filters with enhanced performance and selectivity

Commercial hollow fiber filters for micro- and ultrafiltration are based on size exclusion and do not allow the removal of small molecules such as antibiotics. Here, we demonstrate that a graphene oxide (GO) layer can be firmly immobilized either inside or outside polyethersulfone–polyvinylpyrrolidone hollow fiber (Versatile PES®, hereafter PES) modules and that the resulting core–shell fibers inherits the microfiltration ability of the pristine PES fibers and the adsorption selectivity of GO. GO nanosheets were deposited on the fiber surface by filtration of a GO suspension through a PES cartridge (cut-off 0.1–0.2 μm), then fixed by thermal annealing at 80 °C, rendering the GO coating stably fixed and unsoluble. The filtration cut-off, retention selectivity and efficiency of the resulting inner and outer modified hollow fibers (HF-GO) were tested by performing filtration on water and bovine plasma spiked with bovine serum albumin (BSA, 66 kDa, ≈15 nm size), monodisperse polystyrene nanoparticles (52 nm and 303 nm sizes), with two quinolonic antibiotics (ciprofloxacin and ofloxacin) and rhodamine B (RhB). These tests showed that the microfiltration capability of PES was retained by HF-GO, and in addition the GO coating can capture the molecular contaminants while letting through BSA and smaller polystyrene nanoparticles. Combined XRD, molecular modelling and adsorption experiments show that the separation mechanism does not rely only on physical size exclusion, but involves intercalation of solute molecules between the GO layers

The Effect of Short Chain Carboxylic Acids as Additives on the Crystallization of Methylammonium Lead Triiodide (MAPI)

Due to their exceptional properties, the study of hybrid perovskite (HyP) structures and applications dominate current photovoltaic prospects. Methylammonium lead tri-iodide perovskite (MAPI) is the model compound of the HyP class of materials that, in a few years, achieved, in photovoltaics, a power conversion efficiency of 25%. The attention on HyP has recently moved to large single crystals as emerging candidates for photovoltaic application because of their improved stability and optoelectronic properties compared to polycrystalline films. To control the quality and symmetry of the large MAPI single crystals, we proposed an original method that consisted of adding short-chain carboxylic acids to the inverse temperature crystallization (ICT) of MAPI in γ-butyrolactone (GBL). The crystals were characterized by single-crystal X-ray diffraction (SC-XRD), X-ray powder diffraction (XRPD) and Raman spectroscopy. Based on SC-XRD analysis, MAPI crystals grown using acetic and trifluoroacetic acids adopt a tetragonal symmetry “I4cm”. MAPI grown in the presence of formic acid turned out to crystallize in the orthorhombic “Fmmm” space group demonstrating the acid’s effect on the crystallization of MAPI

The Effect of Short Chain Carboxylic Acids as Additives on the Crystallization of Methylammonium Lead Triiodide (MAPI)

Due to their exceptional properties, the study of hybrid perovskite (HyP) structures and applications dominate current photovoltaic prospects. Methylammonium lead tri-iodide perovskite (MAPI) is the model compound of the HyP class of materials that, in a few years, achieved, in photovoltaics, a power conversion efficiency of 25%. The attention on HyP has recently moved to large single crystals as emerging candidates for photovoltaic application because of their improved stability and optoelectronic properties compared to polycrystalline films. To control the quality and symmetry of the large MAPI single crystals, we proposed an original method that consisted of adding short-chain carboxylic acids to the inverse temperature crystallization (ICT) of MAPI in γ-butyrolactone (GBL). The crystals were characterized by single-crystal X-ray diffraction (SC-XRD), X-ray powder diffraction (XRPD) and Raman spectroscopy. Based on SC-XRD analysis, MAPI crystals grown using acetic and trifluoroacetic acids adopt a tetragonal symmetry “I4cm”. MAPI grown in the presence of formic acid turned out to crystallize in the orthorhombic “Fmmm” space group demonstrating the acid’s effect on the crystallization of MAPI