Universal behavior of photochemical deposition in liquid solutions driven by a one-photon transition

Abstract

Even if photochemical deposition of nearly all types of materials has been used for decades to pattern almost any kind of substrate for various applications (catalysis, chemical sensing, magnetic data storage, optoelectronics, spin-dependent electron transport, and solar cells), a rationalized description is still missing. This paper aims at fulfilling this lack by presenting a unified approach of the photodeposit growth initiated by a one-photon photochemical reaction. We experimentally investigate the robustness of growth scalings predicted for photochemical deposition driven by a continuous laser wave. Three types of one-photon photochemical reactions (photoexcitation of chromates, photodissociation of permanganates, and photocondensation of colloidal selenium) and three parameters (solvent p H variations, concentration in photoactive reagent, and influence of the exciting optical wavelength) were cross analyzed. In all the cases, including data taken from the literature, the same dynamic master behavior emerges from the data rescaling of measured deposit growth laws. The nice agreement observed between system-independent predictions and the whole data set strongly supports a universal description of the photodeposit growth whatever the photosensitive medium and the involved one-photon chemical reaction. Such an approach also points out the quantitative sorting of photochemical reactions in terms of deposition efficiency. This rationalization of the kinetics of photodeposition anticipates new methodologies to predict, design, and control substrate micropatterning for chemical, lithographic, and optoelectronic applications.

Patterning and Substrate Adhesion Efficiencies of Solid Films Photodeposited from the Liquid Phase

“…Indeed, generally speaking, most of the results on photodeposition presented in the literature paid much more attention to the novelty of the nature of the deposited layer than to the conditions required for its deposition and always implicitly assumed the patterning of the induced deposit. However, when we performed experiments on deposit growth, , it appeared that none of these properties were automatically satisfied. Patterning, investigated here using interfering beams, and adhesion were shown to be strongly dependent on the pH of the solutions, on the type of acid, and on the nature of the substrate.…”

“…Finally, experiments are extremely simple to set up because photodeposition is performed in classical homemade tight cells. This flexibility offers the opportunity to deposit a large variety of materials: noble metals (such as Au, , Ag, , Pd, Pt, , or Cu), semiconductors (such as CdS or ZnS, − CdSe or ZnSe, , (Bi, Sb) 2 S 3 , Se x Te 1− x , InS, PbS, Cu x S, CuInS 2 , Sd 1− x Zn x S, FeS x O y ), metal oxides and hydroxide (CrO 2 , Cr(OH) 3 , MnO 2 , SnO 2 , ZnO), polymers, and bio-organic or molecular complexes. , Moreover, irradiating solutions with a well-defined light intensity distribution makes it possible to write in a single step a large variety of patterns in serial (dot and line assemblies, for example) and in parallel (such as holographic gratings) onto both flat and curved solid substrates in contact with the photosensitive solution. Laser light thus behaves as a “smart” pencil, which tailors the material deposition by simply modifying the excitation wavelength, the intensity distribution, and its spatial extension .…”

“…45 Finally, when driven by a one-photon chemical reaction, photodeposition is supported by systemindependent predictions, which make the description of deposit growth universal and allow for the quantitative sorting of photochemical reactions in terms of deposition efficiency. 33 However, as illustrated by the above-mentioned examples, up to now most investigations have concerned the versatility of the technique in either photosensitive precursors or deposited materials. Photodeposition nonetheless requires fulfilling two additional crucial conditions: nucleation at the substrate and adhesion.…”

“…Laser light thus behaves as a “smart” pencil, which tailors the material deposition by simply modifying the excitation wavelength, the intensity distribution, and its spatial extension . Finally, when driven by a one-photon chemical reaction, photodeposition is supported by system-independent predictions, which make the description of deposit growth universal and allow for the quantitative sorting of photochemical reactions in terms of deposition efficiency …”

Unassisted Highly Selective Gas-Phase CO2 Reduction with a Plasmonic Au/p-GaN Photocatalyst Using H2O as an Electron Donor

“…To probe the location of photogenerated hot electrons in the Au/p-GaN heterostructures, we performed plasmon-driven photoreductive deposition of MnO 2 and Cr 2 O 3 using MnO 4 – and CrO 4 2– as precursors in the presence of an methanol as a sacrificial hole scavenger (see Methods). We emphasize that these experiments are commonly used in photocatalytic studies to demonstrate the site of redox reactions and that only reduction reactions are possible with these precursors. ,− As shown in Figure e,f, both photo-reduction deposition reactions using photoexcited electrons occur exclusively on the Au NPs while leaving the surface of p-GaN free of any MnO 2 or Cr 2 O 3 . It is also noted that no MnO 2 or Cr 2 O 3 species were observed on either Au or p-GaN substrates under dark conditions, which rules out the possibility of preferential adsorption of MnO 4 – and CrO 4 2– ions on the Au/p-GaN surface being responsible for the deposition (Figures S3–S5).…”