Enhancement of Solar Energy Absorption and Optoelectronic Properties of SrCuSbS₃ by Lead Doping

Abstract

Copper antimony sulfides (CAS) are of great interest for their applications in solar absorbers. Here, a new series of CAS materials is reported, namely the Sr 1Àx Pb x CuSbS 3 (x ¼ 0-0.2), which are synthesized via solid state reactions. The new compound SrCuSbS 3 crystallizes in the orthorhombic space group Pbam and consists of 3D [CuSbS 3 ] 2À extended framework and Sr 2þ ions. The [CuSbS 3 ] 2À framework is constructed by [CuS 3 ] 5À one-dimensional chains and [SbS 3 ] 3À triangular pyramids. The compound is a semiconductor with a band gap of 1.91 eV. Partial replacement of Sr 2þ by Pb 2þ can narrow the band gap to 1.63 eV when the doping concentration is up to 20%. First-principles calculations reveal that the SrCuSbS 3 compound is a direct band gap semiconductor with the valence band maximum composed of Cu-3d states and the conduction band minimum composed of Sb-5p-S-3p states. The Pb orbitals play critical roles in narrowing the band gap of Sr 1-x Pb x CuSbS 3 (x ¼ 0-0.2). The series of CAS materials also show evident photoelectric response properties which demonstrate their potential for applications for photovoltaic devices. In addition, these CAS materials are good photocatalysts for the photodegradation reaction of Rhodamine B (RhB). The Sr 0.8 Pb 0.2 CuSbS 3 powder can degrade 100% of RhB within 3 h under simulated sunlight.

Rational Crystal Structure Design and Nonlinear-Optical Properties of Noncentrosymmetric RbCu2NbS4

“…The Cu−S bond lengths range from 2.328 to 2.356 Å, which is similar to those in K 2 Cu 2 GeS 4 (2.302−2.548 Å), 37 SrCuSbS 3 (∼2.358 Å),38 and BaCu 4 S 3 (2.282−2.701 Å) 39. The average Nb−S bond length is 2.298 Å, which is comparable to those in the reported structures (2.287 Å in Na 3…”

“…Remarkably, local distortion of the [CuS 4 ] and [NbS 4 ] tetrahedra leads to the local dipole in the structure of RbCu 2 NbS 4 , as illustrated in Figure c. The Cu–S bond lengths range from 2.328 to 2.356 Å, which is similar to those in K 2 Cu 2 GeS 4 (2.302–2.548 Å), SrCuSbS 3 (∼2.358 Å), and BaCu 4 S 3 (2.282–2.701 Å) . The average Nb–S bond length is 2.298 Å, which is comparable to those in the reported structures (2.287 Å in Na 3 NbS 4 and 2.292 Å in NaCu 2 NbS 4 ).…”

Enhanced Photoelectric SrOCuSbS2 of a [SrO]-Intercalated CuSbS2 Structure

“…Remarkably, the current density reaches 3.5 mA/cm 2 at a voltage of 1 V under irradiation (Figure 3a), which is nearly 2 times larger than the dark current of the SrOCuSbS 2 (1.5 mA/cm 2 at 1 V). Under the same condition, the observed 3.5 mA/cm 2 of SrOCuSbS 2 is 2− 6 orders of magnitude higher than the reported 8 μA/cm 2 of KCu 2 SbS 3 , 19 2 nA/cm 2 of CuSbS 2 , 15 0.8 mA/cm 2 of Bi 2 O 2 S, 21 10 μA/cm 2 of Bi 9 O 7.5 S 6 , 22 60 nA/cm 2 of BaCuSbS 3 , 14 54 μA/ cm 2 of Sr 0.8 Pb 0.2 CuSbS 3 , and 35 nA/cm 2 of BaCuSbSe 3 , 14,25 indicating the potential application for photoelectric conversion. Due to intercalation of EIL SrO, the structure creates strong 2D confinement of charge carriers (CuSbS 2 layers along ab planes) and reduces recombination of photogenerated carriers from other directions, which has a higher photoelectric density compared to the parent CuSbS 2 compound.…”

“…Obviously, the absorption edges of SrOCuSbS 2 and AeCuSbS 3 (Ae = Sr, Ba) are similar, in accord with the dark red colors of the crystals. 14,25 The extrapolation of the absorption spectrum estimates that the optical band gap of the title compound is 1.90 eV (Figure 2b). In the temperature range of 140−300 K, the resistivity of the compound shows a semiconductive character and is fitted in both a small polaron hopping model (SPH) and variable range hopping model (VRH; Figure 2c and eqs S1, S2).…”

A novel CuSbS2–TiO2 nanoparticles synergy structure for photocatalysis

“…In recent years, copper based ternary chalcogenides with narrow band gap have been studied, such as CuInS 2 [9], Cu 2 WSe 4 [10], SrCuSbS 3 [11], Cu 3 SbS 3 [12]. As we know, CuSbS 2 (CAS) is a direct band gap material and exhibits tunable band gap of 1.38-1.86 eV with a high absorption coefficient (> 10 4 cm −1 ) in visible light [13][14][15][16][17].…”