Heterojunction Bi₂Se₃/Sb₂Se₃ on Flexible Mo Metal Foils for Photoelectrochemical Water Splitting Applications

Abstract

Nanostructured heterojunctions are an effective approach to enhance the photoelectrochemical (PEC) performance of semiconducting materials, as they facilitate the separation of the photogenerated charge carriers. Here, we report the PEC properties of the Bi 2 Se 3 /Sb 2 Se 3 heterojunction structure on a thin flexible Mo metal foil. Raman spectroscopy confirmed the structural composition of Bi 2 Se 3 and Sb 2 Se 3 with their corresponding vibrational modes. X-ray diffraction showed a rhombohedral crystal structure for Bi 2 Se 3 and an orthorhombic crystal structure for Sb 2 Se 3 on polycrystalline substrates. X-ray photoelectron spectroscopy further revealed the formation of Bi 2 Se 3 and Sb 2 Se 3 compounds corresponding to their chemical and electronic states. PEC measurements were carried out under 100 mW/cm 2 (AM 1.5G) simulated solar radiation in a 0.5 M Na 2 SO 4 aqueous electrolyte solution and demonstrated an enhancement in photocurrent density from the Bi 2 Se 3 /Sb 2 Se 3 heterojunction (127.6 μA/cm 2 ) attributed to more active sites and easy separation of photogenerated charges in comparison to bare Bi 2 Se 3 (7.5 μA/cm 2 ) and Sb 2 Se 3 (76.5 μA/cm 2 ) thin films at 0.9 V vs RHE. This preliminary study on thin metal foil-based photoelectrodes paves the way toward the futuristic production of large-area PEC water-splitting applications.

Nanostructured Bi2Se3-Decorated TiSe2 Pyramids on Ti Foil for Photoelectrochemical Water Splitting

“…The relative increase in photocurrent density on the applied bias voltage is due to the positive effect of the external potential, which could promote the separation and transportation of electron–hole pairs. It is also noticed that both samples have nonzero dark current density, likely due to the leakage current phenomenon that could occur from microstructure defects at the film–metal interface. , …”

“…The V FB values of pristine TiSe 2 and Bi 2 Se 3 /TiSe 2 were found to be 0.32 and 0.24 V vs Ag/AgCl, respectively. The lower value of V FB of Bi 2 Se 3 /TiSe 2 indicates the minimum band bending at the semiconductor electrolyte interface and easy transfer of photogenerated holes to the electrolyte from the electrode and hence improved PEC activity in comparison to that of the pristine TiSe 2 film. , To study the charge carrier dynamics at the electrode–electrolyte interface, we calculated the charge carrier density, also known as donor density ( N D ) close to the electrode–electrolyte interface. The N D was estimated by extracting the slope from a linear fitted Mott–Schottky plot for pristine TiSe 2 and Bi 2 Se 3 /TiSe 2 .…”

Large area MoSe2 and MoSe2/Bi2Se3 films on sapphire (0001) for near-infrared photodetection

“…For sample S2, the three Raman active modes were observed for Bi 2 Se 3 which were present at 76.1. 129.8 and 176.4 cm −1 corresponding to A 1 1g , E 2 g and A 2 1g optical phonon modes, respectively [34]. The three Raman peaks at 169.2, 237.3 and 287.6 cm −1 are assigned to A 1 1g , E 1 1g , and E 1 2g vibrational Raman modes, respectively related to the 2H-phase of MoSe 2 , and the remaining Raman peaks are indexed to sapphire substrate, similar to sample S1 [32,33].…”

MoS2 thin film decorated TiO2 nanotube arrays on flexible Ti foil for solar water splitting application

“…However, there are very few reports on flexible metal foil-based photoelectrode for PEC water splitting and most of the works reported the use of non-bendable brittle, and hard substrates such as silicon, ITO/FTO-coated glass, etc. The use of flexible substrates may enable large-scale rollto-roll PEC devices [37,38]. Some reports on flexible photoelectrode offer a fundamental understanding of developing next-generation roll-to-roll energy device fabrication [38][39][40].…”

“…The use of flexible substrates may enable large-scale rollto-roll PEC devices [37,38]. Some reports on flexible photoelectrode offer a fundamental understanding of developing next-generation roll-to-roll energy device fabrication [38][39][40]. In this work, we have deposited MoS 2 thin film using the CVD technique on TiO 2 nanotube on flexible thin Ti foil.…”