Post‐Synthetic Silver Ion and Sulfurization Treatment for Enhanced Performance in Sb₂Se₃ Water Splitting Photocathodes

Abstract

In the past decade, antimony selenide (Sb2Se3) has made significant progress as a solar energy conversion material. However, the photovoltage deficit continues to pose a challenge and is a major hurdle that must be overcome to reach its maximum solar conversion efficiency. In this study, various post‐synthetic treatments are employed, of which the combination of a solution phase silver nitrate treatment and sulfurization has shown to be the most effective approach to mitigate the photovoltage deficit in this Sb2Se3‐based device. A significant enhancement in the photovoltage is observed after the treatments, as evident by the increase in the onset potential from 0.18 to 0.40 V versus reversible hydrogen electrode. Multiwavelength Raman shows that combining these two treatments removes amorphous Se and metallic Sb from the surface and yields a high‐quality surface layer of Sb2(S1−x, Sex)3 on the bulk Sb2Se3 photoabsorber layer. X‐ray photoelectron spectroscopy with depth profiling reveals extensive incorporation of silver into the film. Density functional theory calculations suggest that silver ions can intercalate between the [Sb4Se6]n ribbons and remain in the Ag+ state. This effective treatment combination brings the practicality of the Sb2Se3 photocathode for water splitting one step closer to large‐scale applications.

Direct Anchoring of Molybdenum Sulfide Molecular Catalysts on Antimony Selenide Photocathodes for Solar Hydrogen Production

“…Only Raman peaks corresponding to the Sb 2 Se 3 phase are observed at this wavelength, as shown in Figure 3c. 23 This indicates that the presence of [Mo 3 S 4 ] 4+ and [Mo 3 S 13 ] 2− clusters on the surface of Sb 2 Se 3 do not induce any structural changes in the Sb 2 Se 3 layer. This was corroborated by XRD measurements (Figure S10), showing no changes in crystal orientation before and after catalyst depositions.…”

“…Herein, we report the suitability of versatile and easy-to-deposit catalysts directly on Sb 2 Se 3 , which include molybdenum sulfide clusters in different configurations, namely [Mo 3 S 4 (H 2 O) 9 ]Cl 4 ([Mo 3 S 4 ] 4+ ) and (NH 4 ) 2 [Mo 3 S 13 ]·2H 2 O ([Mo 3 S 13 ] 2– ). These earth-abundant catalysts can provide up to 20 mA cm –2 at −0.3 V versus reversible hydrogen electrode (RHE) with only a few nanometers thick layers, matching the photocurrents obtained with heterogeneous cocatalysts such as platinum . The easy deposition and simplicity of these molecular catalysts make them excellent candidates for translation to other systems such as photocatalytic particles.…”

“…These earth-abundant catalysts can provide up to 20 mA cm −2 at −0.3 V versus reversible hydrogen electrode (RHE) with only a few nanometers thick layers, matching the photocurrents obtained with heterogeneous cocatalysts such as platinum. 23 The easy deposition and simplicity of these molecular catalysts make them excellent candidates for translation to other systems such as photocatalytic particles. The stability and loading of these catalysts have been studied by using XPS and Raman.…”

Molybdenum Sulfide Clusters as Molecular Co-Catalyst on Antimony Selenide Photocathodes for Photoelectrochemical Hydrogen Evolution

“…These earth-abundant catalysts can provide up to 20 mA cm -2 at -0.3 V versus reversible hydrogen electrode (RHE) with only a few nanometers thick layers, matching the photocurrents obtained with heterogenous cocatalysts such as platinum. 23 The easy deposition and simplicity of these molecular catalysts make them an excellent candidate for translation to other systems such as photocatalytic particles. The stability and loading of these catalysts have been studied using XPS and Raman.…”

“…Only Raman peaks corresponding to the Sb2Se3 phase are observed at this wavelength, as shown in Figure 3c. 23 While the mechanism of action of molybdenum sulphide catalysts is still debated, there are currently two fundamentally different theories of how HER occurs on Mo3Sx. One is a "molybdenum based" catalysis whilst the other is "sulphur based".…”