A life-cycle analysis on thin-film CdS/CdTe PV modules

Authors have evaluated the life cycle of a thin-film CdS/CdTe PV module to estimate the energy payback time (EPT) and the life-cycle CO₂ emissions of a residential rooftop PV system using the CdS/CdTe PV modules. The primary energy requirement for producing 1 m² of the CdS/CdTe PV module was similar to a-Si PV module at annual production scale of 100 MW. EPT was calculated at 1.7–1.1 yr, which was much shorter than the lifetime of the PV system and similar to that of a-Si PV modules. The life-cycle CO₂ emissions were also estimated at 14–9 g-C/kWh, which was less than that of electricity generated by utility companies.     

Impact of the Cd2+ treatment on the electrical properties of Cu2ZnSnSe4 and Cu(In,Ga)Se2 solar cells

The present contribution aims at determining the impact of modifying the properties of the absorber/buffer layer interface on the electrical performance of Cu₂ZnSnSe₄ (CZTSe) thin‐film solar cells, by using a Cd²⁺ partial electrolyte (Cd PE) treatment of the absorber before the buffer layer deposition. In this work, CZTSe/CdS solar cells with and without Cd PE treatment were compared with their respective Cu(In,Ga)Se₂ (CIGSe)/CdS references. The Cd PE treatment was performed in a chemical bath for 7 min at 70 °C using a basic solution of cadmium acetate. X‐ray photoemission spectroscopy measurements have revealed the presence of Cd at the absorber surface after the treatment. The solar cells were characterized using current density–voltage (J–V), external quantum efficiency, and drive‐level capacitance profiling measurements. For the CZTSe‐based devices, the fill factor increased from 57.7% to 64.0% when using the Cd PE treatment, leading to the improvement of the efficiency (η) from 8.3% to 9.0% for the best solar cells. Similar observations were made on the CIGSe solar cell reference. This effect comes from a considerable reduction of the series resistance (R_S) of the dark and light J–V, as determined using the one‐diode model. The crossover effect between dark and light J–V curves is also significantly reduced by Cd PE treatment. Copyright © 2015 John Wiley & Sons, Ltd.     

Electrodeposition of CdS from acidic aqueous thiosulfate solution—Invesitigation of the mechanism by electrochemical quartz microbalance technique

Electrochemical quartz crystal microbalance was used to study mechanism of cathodic electrodeposition of CdS from acidic aqueous solutions containing 0.01 M Cd(ClO₄)₂ and 0.1 M Na₂S₂O₃ as a source of sulfur. Experiments were performed by means of cyclic voltammetry and potentiostatic method. A comparison of gravimetric and current responses at pH 3 and 4 allowed for determination of the potential range in which side reactions of reduction of SO₃²⁻ and H⁺ ions compete most strongly with formation of CdS. The film thickness was determined by means of two methods: from AFM profiles and EQCM measurements.     

Plasmonic-excitonic multi-hybrid glass-based nanocomposites incorporating Ag plus core-shell CdSe/CdS and alloyed CdSxSe1−x nanoparticles

Successful fabrication of glass-based hybrid nanocomposites (GHNCs) incorporating Ag, core-shell CdSe/CdS and CdS_xSe_1?x nanoparticles (NPs) is herein reported. Both metallic (Ag) and semiconductor (CdSe/CdS) NPs were pre-synthesized, suspended in colloids and added into the sol-gel reaction medium which was used to fabricate the GHNCs. During fabrication of the nanocomposites a fraction (20–60%) of core-shell CdSe/CdS NPs was alloyed into CdS_xSe_1?x (0.20 < x < 0.35) NPs without changing morphology. Modulation of in situ alloying is possible via the relative content of organics added into the sol-gel protocol. Within colloids Ag (core-shell CdSe/CdS) NPs presented average diameter and polydispersity index of 49.5 nm (4.2 nm) and 0.41 (0.21), respectively. On the other hand, the Ag (core-shell CdSe/CdS) NPs’ average diameter and polydispersity index assessed from the GHNCs were respectively 51.5 nm (4.1 nm) and 0.43 (0.25), revealing negligible aggregation of the nanophases within the glass template. The new GHNCs herein introduced presented two independent excitonic transitions associated to homogenously dispersed semiconductor NPs, peaking around 420 nm (core-shell CdSe/CdS) and 650 nm (CdS_xSe_1?x) and matching the plasmonic resonance (Ag NPs) in the 400–500 nm range. We envisage that the new GHNCs represent very promising candidates for superior light manipulation while illuminated with multiple laser beams in quantum interference-based devices.     

CdS/Zn-Fe LDO复合材料光催化降解孔雀石绿

采用沉淀法将CdS与锌铁层状双金属氢氧化物（Zn-Fe LDH）复合,高温煅烧后得到CdS/ZnO-ZnFe2O4复合材料（CdS/Zn-Fe LDO）。利用XRD、SEM、UV-vis DRS及PL对复合材料的结构、形貌、光学性能进行了表征。研究了该复合材料在可见光下对孔雀石绿的光降解,结果表明：CdS/Zn-Fe LDO复合材料对孔雀石绿的光催化降解能力高于CdS或Zn-Fe LDO,其中,m(CdS) : m(Zn-Fe LDH)=1 : 1配比制备的CdS/Zn-Fe LDO（1:1）光催化活性最大。光照20 min,20 mg CdS/Zn-Fe LDO（1:1）对20 mg/L孔雀石绿的光降解率为96.6%。此外,该复合材料还可降解罗丹明B、亚甲基蓝、甲基橙、结晶紫等染料且光降解反应符合一级反应动力学。     

Visible Light-Induced Degradation of Methylene Blue in the Presence of Photocatalytic ZnS and CdS Nanoparticles

ZnS and CdS nanoparticles were prepared by a simple microwave irradiation method under mild conditions. The obtained nanoparticles were characterized by XRD, TEM and EDX. The results indicated that high purity of nanosized ZnS and CdS was successfully obtained with cubic and hexagonal crystalline structures, respectively. The band gap energies of ZnS and CdS nanoparticles were estimated using UV-visible absorption spectra to be about 4.22 and 2.64 eV, respectively. Photocatalytic degradation of methylene blue was carried out using physical mixtures of ZnS and CdS nanoparticles under a 500-W halogen lamp of visible light irradiation. The residual concentration of methylene blue solution was monitored using UV-visible absorption spectrometry. From the study of the variation in composition of ZnS:CdS, a composition of 1:4 (by weight) was found to be very efficient for degradation of methylene blue. In this case the degradation efficiency of the photocatalyst nanoparticles after 6 h irradiation time was about 73% with a reaction rate of 3.61 × 10⁻³ min⁻¹. Higher degradation efficiency and reaction rate were achieved by increasing the amount of photocatalyst and initial pH of the solution.     

New Preparation Method of CdS Clusters Encapsulated in Y-Type Zeolites

CdS clusters encapsulated in Y-type zeolite were prepared by a novel technique with non-aqueous systems. The mechanical mixture of CdCl₂· 2.5H₂O crystal with Y-type zeolite was heated at 773 K, followed by the H₂S treatment at 373 K, resulting in the formation of CdS clusters with the size <2.3 nm.     

Ordered Mesostructured CdS Nanowire Arrays with Rectifying Properties

Highly ordered mesoporous CdS nanowire arrays were synthesized by using mesoporous silica as hard template and cadmium xanthate (CdR₂) as a single precursor. Upon etching silica, mesoporous CdS nanowire arrays were produced with a yield as high as 93 wt%. The nanowire arrays were characterized by XRD, N₂ adsorption, TEM, and SEM. The results show that the CdS products replicated from the mesoporous silica SBA-15 hard template possess highly ordered hexagonal mesostructure and fiber-like morphology, analogous to the mother template. The current–voltage characteristics of CdS nanoarrays are strongly nonlinear and asymmetrical, showing rectifying diode-like behavior.     

Trioctylphosphine as Both Solvent and Stabilizer to Synthesize CdS Nanorods

High quality CdS nanorods are synthesized reproducibly with cadmium acetate and sulfur as precursors in trioctylphosphine solution. The morphology, crystalline form and phase composition of CdS nanorods are characterized by transmission electron microscopy (TEM), high-resolution TEM and X-ray diffraction (XRD). CdS nanorods obtained are uniform with an aspect ratio of about 5:1 and in a wurtzite structure. The influence of reaction conditions on the growth of CdS nanorods demonstrates that low precursor concentration and high reaction temperature (260 °C) are favorable for the formation of uniform CdS nanorods with 85.3% of product yield.