Spin coating on a budget: A 3D-Printed all-mechanical alternative for cost-effective thin-film deposition.

Spin coating stands out as the most employed thin-film deposition technique across a variety of scientific fields. Particularly in the past two decades, spin coaters have become increasingly popular due to the emergence of solution-processed semiconductors such as quantum dots and perovskites. However, acquiring commercial spin coaters from reputable suppliers remains a significant financial burden for many laboratories, particularly for smaller research or educational facilities.

Electron transfer and energy exchange between a covalent organic framework and CuFeS nanoparticles.

CuFeS is a prominent chalcogenide that possesses similar optical properties and a significantly lower cost, compared to gold. Additionally, covalent organic frameworks are a class of materials at the forefront of current research, mainly used as photoactive components and porous absorbers. Hence, in this work, hydrophilic CuFeS particles are coupled with multi-functional covalent organic frameworks through ionic bonding to produce a hybrid material with unique and optimized properties.

Light concentration and electron transfer in plasmonic-photonic Ag,Au modified Mo-BiVO inverse opal photoelectrocatalysts.

Plasmonic photocatalysis based on metal-semiconductor heterojunctions is considered a key strategy to evade the inherent limitations of poor light harvesting and charge separation of semiconductor photocatalysts. It can be profitably combined with three-dimensional photonic crystals (PCs) that offer an ideal scaffold for loading plasmonic nanoparticles and a unique architecture to intensify photon capture. In this work, Mo-doped BiVO inverse opals were applied as visible light-responsive photonic hosts of Ag and/or Au plasmonic nanoparticles in order to exploit the synergy of plasmonic and photonic amplification effects with interfacial charge transfer for the photoelectrocatalytic degradation of recalcitrant pharmaceutical contaminants under visible light.

Photonic nanostructures mimicking floral epidermis for perovskite solar cells.

Here, we report photonic nanostructures replicated from the adaxial epidermis of flower petals onto light-polymerized coatings using low-cost nanoimprint lithography at ambient temperature. These multifunctional nanocoatings are applied to confer enhanced light trapping, water repellence, and UV light and environmental moisture protection features in perovskite solar cells. The former feature helps attain a maximum power conversion efficiency of 24.

Perovskites with d-block metals for solar energy applications.

Pb2+ halide organic-inorganic perovskites are excellent semiconductors for use in solar energy applications, but at the expense of robustness and environmental compatibility. Tin (Sn), which sits just above lead in the periodic table, forms pure (or mixed with lead) perovskites when at the 2+ or 4+ oxidation state. It can act as a promising alternative; however, there are still some serious concerns regarding its suitability.

Effect of Structural Phase Transition on Charge-Carrier Lifetimes and Defects in CH3NH3SnI3 Perovskite.

Methylammonium tin triiodide (MASnI3) has been successfully employed in lead-free perovskite solar cells, but overall power-conversion efficiencies are still significantly lower than for lead-based perovskites. Here we present photoluminescence (PL) spectra and time-resolved PL from 8 to 295 K and find a marked improvement in carrier lifetime and a substantial reduction in PL line width below ∼110 K, indicating that the cause of the hindered performance is activated at the orthorhombic to tetragonal phase transition. Our measurements therefore suggest that targeted structural change may be capable of tailoring the relative energy level alignment of defects (e.

Employing PEDOT as the p-Type Charge Collection Layer in Regular Organic-Inorganic Perovskite Solar Cells.

Organic-inorganic halide perovskite solar cells have recently emerged as high-performance photovoltaic devices with low cost, promising for affordable large-scale energy production, with laboratory cells already exceeding 20% power conversion efficiency (PCE). To date, a relatively expensive organic hole-conducting molecule with low conductivity, namely spiro-OMeTAD (2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine) 9,9'- spirobifluorene), is employed widely to achieve highly efficient perovskite solar cells. Here, we report that by replacing spiro-OMeTAD with much cheaper and highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) we can achieve PCE of up to 14.

Formation of thin films of organic-inorganic perovskites for high-efficiency solar cells.

Organic-inorganic perovskites are currently one of the hottest topics in photovoltaic (PV) research, with power conversion efficiencies (PCEs) of cells on a laboratory scale already competing with those of established thin-film PV technologies. Most enhancements have been achieved by improving the quality of the perovskite films, suggesting that the optimization of film formation and crystallization is of paramount importance for further advances. Here, we review the various techniques for film formation and the role of the solvents and precursors in the processes.

Ultrasmooth organic-inorganic perovskite thin-film formation and crystallization for efficient planar heterojunction solar cells.

To date, there have been a plethora of reports on different means to fabricate organic-inorganic metal halide perovskite thin films; however, the inorganic starting materials have been limited to halide-based anions. Here we study the role of the anions in the perovskite solution and their influence upon perovskite crystal growth, film formation and device performance. We find that by using a non-halide lead source (lead acetate) instead of lead chloride or iodide, the perovskite crystal growth is much faster, which allows us to obtain ultrasmooth and almost pinhole-free perovskite films by a simple one-step solution coating with only a few minutes annealing.

Fast Recovery of the High Work Function of Tungsten and Molybdenum Oxides via Microwave Exposure for Efficient Organic Photovoltaics.

In this work, we use microwave exposure of tungsten and molybdenum oxides to improve hole extraction in organic photovoltaics (OPVs). This is a result of fast recovery of the high work function of metal oxides occurring within a few seconds of microwave processing. Using the space-charge-limited current model, we verified the formation of an anode contact that facilitates hole extraction, while Mott-Schottky analysis revealed the enhancement of the device built-in field in the devices with the microwave-exposed metal oxides.

Novel Ru(II) sensitizers bearing an unsymmetrical pyridine-quinoline hybrid ligand with extended π-conjugation: synthesis and application in dye-sensitized solar cells.

Heteroleptic ruthenium(II) sensitizers DV42 and DV51, encompassing a novel unsymmetrical pyridine-quinoline hybrid ligand with extended π-conjugation, were synthesized, characterized, and utilized in nanocrystalline dye-sensitized solar cells. Due to the extended conjugation of DV42 and DV51, the absorption of the corresponding sensitized TiO2 films extends into the red spectral range, shifted by 30-40 nm relative to the absorption of TiO2 films sensitized with the standard Z907 ruthenium(II) dye. Contact angle measurements of DV42- and DV51-sensitized TiO2 films suggest that these films are hydrophilic with contact angle values commonly observed upon sensitization with the standard N3 ruthenium(II) dye.

Influence of electrolyte co-additives on the performance of dye-sensitized solar cells.

The presence of specific chemical additives in the redox electrolyte results in an efficient increase of the photovoltaic performance of dye-sensitized solar cells (DSCs). The most effective additives are 4-tert-butylpyridine (TBP), N-methylbenzimidazole (NMBI) and guanidinium thiocyanate (GuNCS) that are adsorbed onto the photoelectrode/electrolyte interface, thus shifting the semiconductor's conduction band edge and preventing recombination with triiodides. In a comparative work, we investigated in detail the action of TBP and NMBI additives in ionic liquid-based redox electrolytes with varying iodine concentrations, in order to extract the optimum additive/I2 ratio for each system.

TiO2 nanotubes in dye-sensitized solar cells: critical factors for the conversion efficiency.

Particle vs tube: The present paper systematically investigates a range of fundamental geometrical and structural features of TiO(2) nanotube layers and their effect on the dye-sensitized solar cell conversion efficiency, to deduce the most promising strategies for improvement. It is found that the performance of the cells strongly depends on the morphology and crystalline structure of the nanotubes.