Unravelling Defect Passivation Mechanisms in Sulfur-treated Sb2Se3

Abstract

<p>Sb<sub>2</sub>Se<sub>3 </sub>has emerged as an important photoelectrochemical (PEC) and photovoltaic (PV) material due to its rapid rise in photoconversion efficiencies. However, despite its binary nature, Sb<sub>2</sub>Se<sub>3 </sub>has a complex defect chemistry, which reduces the maximum photovoltage that can be obtained. Thus, it is important to understand these defects and to develop passivation strategies in order to further improve this material. In this work, a comprehensive investigation of the charge carrier dynamics of Sb<sub>2</sub>Se<sub>3</sub> and the influence of sulfur treatment on its optoelectronic properties was performed using time resolved microwave conductivity (TRMC), photoluminescence (PL) spectroscopy and low frequency Raman spectroscopy (LFRS). The key finding in this work is that upon sulfur treatment of Sb<sub>2</sub>Se<sub>3</sub>, the carrier lifetime is increased by the passivation of deep defects in Sb<sub>2</sub>Se<sub>3</sub> in both the surface region and the bulk, which is evidenced by increased charge carrier lifetime of TRMC decay dynamics, increased radiative recombination efficiency and decreased deep defect level emission (PL), and improved long-range order in the material (LFRS). These findings provide crucial insights into the defect passivation mechanisms in Sb<sub>2</sub>Se<sub>3</sub> paving the way for developing highly efficient PEC and PV devices.</p>

Identification of Enantiomers Using Low-Frequency Raman Spectroscopy

“…21−25 Any level of symmetry or orderliness in the material at its lattice enables us to better resolve these modes which makes it an ideal tool to understand different characteristics such as crystallinity, long range order, and defect-induced changes in the material including defect-induced orderliness. 26,27 In an ordered sample such as a single crystal, these modes are polarization-dependent. The scattering cross section of these modes differs in different polarization directions.…”

A durable VO2 transition layer and defect inactivation in BiVO4via spontaneous valence-charge control

“…6,7 These semiconductor photoelectrodes must be designed for sufficient light absorption, effective charge separation, long-term stability, and high surface reactivity. 8,9 In this context, bismuth vanadate (BiVO 4 ) has attracted particular attention owing to its appropriate bandgap (2.4 eV) and suitable band-edge positions. 8,10,11 It also possesses a favorable surface and bulk structure with a lower onset potential (and/or longer carrier-diffusion length) than those of other potential photoanodes such as a-Fe 2 O 3 ($2.1 eV), [12][13][14] CuWO 4 ($2.3 eV), 15 CuV 2 O 6 ($1.84 eV), 16 or ZnFe 2 O 4 ($2.0 eV).…”