The Aims of the Criminal Law

Cu2ZnSnS4(CZTS) is an interesting material for sustainable photovoltaics, but efficiencies are limitedby the low open-circuit voltage. A possible cause of this is disorder among the Cu and Zn cations, aphenomenon which is difficult to detect by standard techniques. We show that this issue can beovercome using near-resonant Raman scattering, which lets us estimate a critical temperature of 533±10 K for the transition between ordered and disordered CZTS. These findings have deepsignificance for the synthesis of high-quality material, and pave the way for quantitative investigationof the impact of disorder on the performance of CZTS-based solar cells.kestCa

A low-temperature order-disorder transition in Cu2ZnSnS4 thin films

Cu2ZnSnS4(CZTS) is an interesting material for sustainable photovoltaics, but efficiencies are limitedby the low open-circuit voltage. A possible cause of this is disorder among the Cu and Zn cations, aphenomenon which is difficult to detect by standard techniques. We show that this issue can beovercome using near-resonant Raman scattering, which lets us estimate a critical temperature of 533±10 K for the transition between ordered and disordered CZTS. These findings have deepsignificance for the synthesis of high-quality material, and pave the way for quantitative investigationof the impact of disorder on the performance of CZTS-based solar cells.kestCa

Surface preparation for 10% efficient CZTSe solar cells

International audienc

On the role of sodium and copper off‐stoichiometry in Cu (In,Ga)S 2 for photovoltaic applications: Insights from the investigation of more than 500 samples

International audienceThe present article discusses the investigation of CuIn1-xGaxS2 (CIGS) thin films for photovoltaic applications. For decades, a Cu-rich composition has been used to create solar cells with efficiencies of up to 13.5%; however, interest in chalcopyrite sulfide has recently been revived due to its high and adjustable bandgap, making it a serious candidate as a top cell in tandem configurations. Although chalcopyrite selenides share many properties with CIGS thin films, crucial differences have been reported. To further understand these materials, we studied more than 500 samples of absorbers and resulting solar cells. First, we found that the compositional window for obtaining single-phase CIGS thin films with a three-stage co-evaporation process is very narrow. Second, we reported that a combination of low copper content and sodium addition during growth is required to maximize the photoluminescence intensity (i.e., to minimize the absorber-related open-circuit voltage losses). Finally, we showed that solar cell performance and stability depend not only on absorber quality but also on phenomena at interfaces (absorber/buffer and grain boundaries). Altogether, we formulate growth recommendations for the manufacture of stable CIGS/CdS solar cells with state-of-the-art efficiency

Electrocatalyst Derived from Waste Cu–Sn Bronze for CO2 Conversion into CO

To sustainably exist within planetary boundaries, we must greatly curtail our extraction of fuels and materials from the Earth. This requires new technologies based on reuse and repurposing of material already available. Electrochemical conversion of CO2 into valuable chemicals and fuels is a promising alternative to deriving them from fossil fuels. But most metals used for electrocatalysis are either endangered or at serious risk of limitation to their future supply. Here, we demonstrate a combined strategy for repurposing of a waste industrial Cu–Sn bronze as a catalyst material precursor and its application toward CO2 reuse. By a simple electrochemical transfer method, waste bronzes with composition Cu14Sn were anodically dissolved and cathodically redeposited under dynamic hydrogen bubble template conditions to yield mesoporous foams with Cu10Sn surface composition. The bimetal foam electrodes exhibited high CO2 electroreduction selectivity toward CO, achieving greater than 85% faradaic efficiency accompanied by a considerable suppression of the competing H2 evolution reaction. The Cu–Sn foam electrodes showed good durability over several hours of continuous electrolysis without any significant change in the composition, morphology, and selectivity for CO as a target product