silicon solar cell. [3][4][5][6] Pb-based halide perovskites have shown remarkable and unique PV properties compared to silicon such as tunable bandgaps, high optical absorption coefficients, balanced effective masses of electrons and holes, longer diffusion lengths, extended lifetimes of the photogenerated charge carriers, and smaller exciton binding energies. [7][8][9] Facile fabrication technology with high defect tolerance is another advantage in Pb-based halide perovskites. However, a major problem to be solved is the toxicity of the element lead (Pb) in halide perovskites, let alone moisture and air sensitivities. The toxicity issue should be solved by finding new alternative materials for substituting Pb, and one of the alternatives can be Bi 3þ -or Sb 3þ -based perovskites. Several combinations of elements together with Bi 3þ or Sb 3þ ions are proposed to be possible based on the theoretical calculations, but only a few materials have been experimentally synthesized. [10] In the case of Bi 3þ , the research focus has been devoted to Cs 2 AgBiBr 6 due to its high stability and nontoxicity. [11] Especially Cs 2 AgBiBr 6 was theoretically and experimentally tested to be a potential candidate for photovoltaic application due to its long charge carrier lifetime compared to the other potential Pbfree perovskites. [12][13][14][15][16][17] Some of the highest power conversion efficiencies (PCEs) are reported to be 2.84% [18] and 3.11%. [19] Compared to Pb-based halide perovskites, the indirect bandgap
In view of rising ecological awareness, materials development is primarily aimed at improving the performance and efficiency of innovative and more elaborate materials. However, a materials performance figure of merit should include essential aspects of materials: environmental impact, economic constraints, technical feasibility, etc. Thus, we promote the inclusion of sustainability criteria already during the materials design process. With such a holistic design approach, new products may be more likely to meet the circular economy requirements than when traditional development strategies are pursued. Using catalysts for water electrolysis as an example, we present a modelling method based on experimental data to holistically evaluate processes.
Nontoxic, all-inorganic
perovskite light absorbers have
received
a great deal of attention in recent years due to their potential to
replace lead-containing perovskite materials in photovoltaics. Herein,
the synthesis of the lead-free double perovskite Cs2AgBiBr6 as a powder, obtained via spray-drying,
is reported to be capable of paving the way toward large scale production.
Upon drying of the atomized precursor solution during spray-drying, the double-perovskite phase forms by in situ crystallization.
The product that is obtained from spray-drying is
compared to the one that is obtained from the so-called solution
cooling method, which is often used for the absorber synthesis
before dissolving the double perovskite powder for the thin film deposition.
The absorber powder gained from the solution cooling method sets the benchmark for the spray-dried absorber powder. XRD and
Raman analyses confirm the phase purity of the double perovskite,
whereas UV–Vis spectroscopy
confirms the desired bandgap. Furthermore, the absorber powders from
both synthesis methods are successfully used to deposit and integrate
absorber films in single-junction perovskite solar cells. Besides
being introduced as an alternative synthesis route for the preparation
of double perovskite absorber as dry powders independently from being
applied onto a given substrate, the superior advantages of spray-drying compared to the conventional synthesis of the
perovskite absorber via the solution cooling method are outlined: Spray-drying not only enables the
synthesis of large amounts of perovskite absorber powders but also
discards the usage of precarious solvents like concentrated hydrobromic
acid and thus eliminates the need for extensive safety precautions.
Hence, spray-drying may help the perovskite technology
take the next step toward large-scale production and commercialization.
The half-Heusler (HH) compound NbCoSn
with 18 valence electrons
is a promising thermoelectric (TE) material due to its appropriate
electrical properties as well as its suitable thermal and chemical
stability. Nowadays, doping/substitution and tailoring of microstructures
are common experimental approaches to enhance the TE performance of
HH compounds. However, detailed theoretical insights into the effects
of doping on the microstructures and TE properties are still missing.
In this work, the microstructure of NbCoSn was tailored through precipitating
the full-Heusler phases in the matrix by changing the nominal ratio
of Co and Ni on the Co sites, focusing on the resulting TE properties.
Further, first-principles calculations were employed to understand
the relationship between the microstructure and the TE properties
from the thermodynamic point of view. Detailed analysis of the electronic
structure reveals that the presence of excess Co/Ni contributes to
the increasing carrier concentration. Through an increase in the electrical
conductivity and a reduction in the thermal conductivity, the TE performance
is improved. Therefore, the present work offers a new pathway and
insights to enhance the TE properties by modifying the microstructure
of HH compounds via tailoring the chemical compositions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.