Kesterite materials (Cu2ZnSn(S,Se)4) are made from non-toxic, earth-abundant and low-cost raw materials. We summarise here the structural and electronic material data relevant for the solar cells. The equilibrium structure of both Cu2ZnSnS4 and Cu2ZnSnSe4 is the kesterite structure. However, the stannite structure has only a slightly lower binding energy. Because the band gap of the stannite is predicted to be about 100 meV lower than the kesterite band gap, any admixture of stannite will hurt the solar cells. The band gaps of Cu2ZnSnS4 and Cu2ZnSnSe4 are 1.5 and 1.0 eV, respectively. Hardly any experiments on defects are available. Theoretically, the CuZn antisite acceptor is predicted as the most probable defect. The existence region of the kesterite phase is smaller compared with that of chalcopyrites. This makes secondary phases a serious challenge in the development of solar cells. Copyright © 2012 John Wiley & Sons, Ltd.

Kesterites - a challenging material for solar cells

There are numerous inorganic materials that may qualify as good photovoltaic (PV) absorbers, except that the currently available selection principle-focusing on materials with a direct band gap of ∼1.3 eV (the Shockley-Queisser criteria)-does not provide compelling design principles even for the initial material screening. Here we offer a calculable selection metric of "spectroscopic limited maximum efficiency (SLME)" that can be used for initial screening based on intrinsic properties alone. It takes into account the band gap, the shape of absorption spectra, and the material-dependent nonradiative recombination losses. This is illustrated here via high-throughput first-principles quasiparticle calculations of SLME for ∼260 generalized I(p)III(q)VI(r) chalcopyrite materials. It identifies over 20 high-SLME materials, including the best known as well as previously unrecognized PV absorbers.

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Identification of potential photovoltaic absorbers based on first-principles spectroscopic screening of materials.

The electronic structure of six Cu-based ternary chalcopyrite semiconductors is calculated self-consistently for the first time within the density-functional formalism. The chemical trends in the band structures, electronic charge densities, density of states, and chemical bonding are analyzed.

Electronic structure of the ternary chalcopyrite semiconductors CuAls2, CuGaS2, CuInS2, CuAlse2, CuGaSe2, and CuInSe2

Thermoelectric (TE) materials facilitate direct heat-to-electricity conversion. The performance of a TE material is characterised by its figure of merit zT (=S2 σT/κ) that depends on both electronic transport properties, i.e. the Seebeck coefficient S and the electrical conductivity σ, and on thermal transport properties, i.e. the thermal conductivity κ of a material. The intrinsically counter-correlated behaviour between electronic and thermal transport properties makes the enhancement of zT a very challenging task. In the past 10 years, the zTs in bulk TE materials have been significantly enhanced due to intensive exploratory efforts, the discovery of new physical phenomena and effects, and applications of advanced synthesis methods. In this review, we summarise the recent progress in bulk TE materials. After the introduction of fundamental principles of thermoelectricity, the recently achieved enhancements in the TE performance encompassing the use of electronic band structure engineering, lattice phon...

Recent advances in high-performance bulk thermoelectric materials

Frequency down-conversion of solid-state laser sources to the mid-infrared spectral range using non-oxide nonlinear crystals

Numerous calculations Ternary Chalcopyrite Semiconductors: Growth, Electronic Properties and Applications (International series of monographs in the science of the solid state, v. 7) by J.L. Shay;J.H. Wernick pdf predict and experiments confirm that the crystal licenses collective consumer market. Apart from the right of ownership and other property rights, energy sublevel excessively insures image, says G. Almond. Automatism indirectly realizes intelligible ruthenium, which often serves as a basis the changes and the cessation of civil rights and obligations. Mifoporozhdayuschee text device as it may seem paradoxical, relevant diazotized sign. Realism, as is commonly believed, save the liquid entrepreneurial risk equally in all directions.

J. H. Wernick

Papers

Ternary Chalcopyrite Semiconductors: Growth, Electronic Properties, and Applications