In this contribution, we present a new certified world record efficiency of 20.1 and 20.3% for Cu(In,Ga)Se2 thin-film solar cells. We analyse the characteristics of solar cells on such a performance level and demonstrate a high degree of reproducibility. Copyright © 2011 John Wiley & Sons, Ltd.

New world record efficiency for Cu(In,Ga)Se2 thin‐film solar cells beyond 20%

Since the discovery of superconductivity above 30 K by Bednorz and M\"uller in the La copper oxide system, the critical temperature has been raised to 90 K in Y${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ and to 110 and 125 K in Bi-based and Tl-based copper oxides, respectively. In the two years since this Nobel-prize-winning discovery, a large number of electronic structure calculations have been carried out as a first step in understanding the electronic properties of these materials. In this paper these calculations (mostly of the density-functional type) are gathered and reviewed, and their results are compared with the relevant experimental data. The picture that emerges is one in which the important electronic states are dominated by the copper $d$ and oxygen $p$ orbitals, with strong hybridization between them. Photon, electron, and positron spectroscopies provide important information about the electronic states, and comparison with electronic structure calculations indicates that, while many features can be interpreted in terms of existing calculations, self-energy corrections ("correlations") are important for a more detailed understanding. The antiferromagnetism that occurs in some regions of the phase diagram poses a particularly challenging problem for any detailed theory. The study of structural stability, lattice dynamics, and electron-phonon coupling in the copper oxides is also discussed. Finally, a brief review is given of the attempts so far to identify interaction constants appropriate for a model Hamiltonian treatment of many-body interactions in these materials.

Electronic structure of the high-temperature oxide superconductors

Premises of creation of Internet portal designed to provide access to participants of educational and scientific process for the joint creation, consolidation, concentration and rapid spreading of educational and scientific information resources in its own depository are considered. CMS-based portal content management systems’ potentiality is investigated. Architecture for Internet portal of MES of Ukraine’s information resources is offered.

Створення порталу інформаційно-довідкових ресурсів міністерства освіти і науки україни

Solar photovoltaic electricity: Current status and future prospects

The discovery of 30-K superconductivity in the La–Ba–Cu–O system1 and 90-K superconductivity in the Y–Ba–Cu–O system2 stimulated a worldwide search for even higher-temperature superconductors. Unfortunately, most of the higher-temperature transitions reported in the past year have proved to be unstable, irreproducible, or not due to bulk superconductivity3–7. Recently, we and co-workers8,9 reported superconductivity above 90 K in a new Tl–Ba–Cu–O system, and pointed out that elemental substitutions in this system may lead to even higher-temperature superconductivity. Here we report stable and reproducible bulk superconductivity with an onset at 120 K and zero resistance above 100 K in the Tl–Ca/Ba–Cu–O system. This transition temperature is much higher than those observed for typical rare-earth-containing superconductors, and the onset temperatures are comparable to that in the Bi–Ca/Sr–Cu–O system, as reported in refs 10 and 11 (received after submission of this paper).

Bulk superconductivity at 120 K in the Tl-Ca/Ba-Cu-O system

Mesures d'attenuation d'ultrasons sur des supraconducteurs a haute temperature a base de Thallium ayant une temperature de transition voisine de 110 K. Mesures effectuees entre 300 K et la temperature de l'Azote liquide (77 K). Observation de plusieurs pics accompagnes d'un pic supplementaire au voisinage de Tc. A la temperature critique, aucune chute aigue n'est observee avec la resolution experimentale disponible. L'attenuation croit avec l'abaissement de la temperature en dessous de Tc. Observation d'un comportement d'attenuation similaire dans les complexes a base de Y

Ultrasonic attenuation measurements on thallium-based high-temperature superconductors

Thermoelectric power of Tl-Ca-Ba-Cu-O and Pr-Tl-Sr-Ca-Cu-O high Tc superconductors

The effect of pressure on high- T c superconductors was studied by Josephson absorption as a new and very accurate method for determination of the critical temperature. The uncertainty in T c was less than 0.06 K. We propose our method as a new standard of T c measurements. The pressure derivative d T c /d p equals 1.06 K GPa -1 for YBa 2 Cu 3 O 7−λ and 2.20 K GPa -1 for Tl-Ca-Ba-Cu-O ceramics. Absence of thermal hysteresis was observed. The change of microwave absorption under hydrostatic pressure was also investigated.

Pressure study of Tc and Josephson absorption in YBa2Cu3O7−λ and Tl-Ca-Ba-Cu-O superconductors

A high temperature superconducting system has the general composition Tl-R-X-Y, wherein: R is a Group 2A element; X is a Group 1B element; and Y is a Group 6A element. Preferably, the composition has the following formula Tl-Ba-Cu-O. The high temperature superconductor of the present invention has a transition temperature of about 90 K with the probability of one phase superconducting at a temperature perhaps as high as 270 K. Processes for making the high temperature superconductor are also provided.

/pdf/high-temperature-superconductor-system-and-processes-for-5faozqhjez.pdf

High temperature superconductor system and processes for making same

A process of making high temperature Tl-based 
superconductors includes reacting solid Ba-Ca-Cu-oxides 
with Tl₂O₃ vapour. The process allows high quality Tl-­
based superconductors to be prepared easily.

/pdf/process-for-making-tl-ba-ca-gu-o-superconductors-5fhv5eqjln.pdf

Allen M. Hermann

Papers

Ultrasonic attenuation measurements on thallium-based high-temperature superconductors

Thermoelectric power of Tl-Ca-Ba-Cu-O and Pr-Tl-Sr-Ca-Cu-O high Tc superconductors

Pressure study of Tc and Josephson absorption in YBa2Cu3O7−λ and Tl-Ca-Ba-Cu-O superconductors

High temperature superconductor system and processes for making same

Process for making tl-ba-ca-gu-o superconductors