Johann Summhammer - Academia.edu (original) (raw)

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Papers by Johann Summhammer

International Journal of Theoretical Physics, 1994

arXiv (Cornell University), Oct 7, 2021

World Conference on Photovoltaic Energy Conversion, Nov 18, 2009

A solar cell format of 156 x 39 mm is proposed and tested for multicrystalline silicon solar cell... more A solar cell format of 156 x 39 mm is proposed and tested for multicrystalline silicon solar cells. These so called "QuarterCells" are made from standard wafers of 156 x156 mm, but with a modified front and back metallization pattern. The rectangular format allows an interconnection of the cells with short, thin pieces of wire. This results in lower shading of active silicon area and in much lower resistive losses between the cells, such that a total gain in power output of 4.4% is expected. Simultaneously the copper needed for the interconnection of cells is reduced by more than 50%. First tests on real modules confirm the expected advantages.

Physica B-condensed Matter, Oct 1, 1991

Journal of materials chemistry. A, Materials for energy and sustainability, 2017

Physics Letters, Oct 1, 1999

23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain, Nov 1, 2008

arXiv (Cornell University), Nov 15, 2016

Physics Letters, Dec 1, 1994

Thin Solid Films, May 1, 2013

ABSTRACT Electrical properties of thin film photovoltaic modules exhibit metastable behavior when... more ABSTRACT Electrical properties of thin film photovoltaic modules exhibit metastable behavior when exposed to light, when kept in the dark after light exposure and as a result of external bias. These effects vary in magnitude and expression and can mainly be observed in CdTe and chalcopyrites. The light-soaking induced effect in these technologies was analyzed for electrical module parameters such as open circuit voltage (Voc), short circuit current, fill factor (FF), maximum power point (Pmpp) and the current–voltage characteristic slope at Voc. The influence of the light-soaking irradiance and the duration of the illumination at constant temperature was investigated. Furthermore, light-soaking with additional external bias was examined. Overall, all modules showed metastable behavior with increases in the FF, the Voc and the Pmpp after light-soaking. The magnitude varied for different technologies and was largest for the investigated CdTe modules. Differences among the technologies could be observed for the change in Voc. While CdTe exhibited a significant increase in both FF and Voc, Cu(In,Ga)Se2 (CIGS) modules mainly showed an increase in the FF. Differences in metastable behavior were also observed for relaxation times in the dark. While CdTe modules returned to the initial levels in several hours, it took several weeks for the CIGS modules to relax. The presented experiments confirm that metastabilities reported on cell behavior also occur at the module level.

Physical Review Letters, Aug 31, 1987

arXiv (Cornell University), Mar 15, 2005

The physical concept of quantum entanglement is brought to the biological domain. We simulate the... more The physical concept of quantum entanglement is brought to the biological domain. We simulate the cooperation of two insects by hypothesizing that they share a large number of quantum entangled spin-1/2 particles. Each of them makes measurements on these particles to decide whether to execute certain actions. In the first example, two ants must push a pebble, which may be too heavy for one ant. In the second example, two distant butterflies must find each other. In both examples the individuals make odour-guided random choices of possible directions, followed by a quantum decision whether to push/fly or to wait. With quantum entanglement the two ants can push the pebble up to twice as far as independent ants, and the two butterflies may need as little as half of the flight path of independent butterflies to find each other.

Physical Review A, Jun 9, 2000

$Research paper thumbnail of Testing energy quantization at the level of 100 kHz by neutron crystal diffraction$

Physical Review A, Oct 1, 1996

ABSTRACT For the study of energy quantization in low-frequency potentials and the accompanying qu... more ABSTRACT For the study of energy quantization in low-frequency potentials and the accompanying quantum effects we analyze a silicon double-crystal arrangement exploiting dynamical diffraction of neutrons to achieve the required extremely high energy resolution. The first crystal prepares a minimum-uncertainty beam that passes a potential region whose influence on the neutron energy is analyzed by the second crystal. With realistic parameters, changes of neutron energy below 0.5 neV can be resolved. This permits a test of quantized energy transfer in periodically time-dependent potentials of a frequency below 100 kHz. We also discuss three specific examples how to observe the quantum phenomena arising from the macroscopic wave packets thereby generated.

Physical review, Nov 1, 1987

ECS transactions, May 19, 2016

Physics Letters, Apr 1, 1989

Foundations of Physics Letters, Jun 1, 1988

ABSTRACT In quantum physics all experimental information is discrete and stochastic. But the valu... more ABSTRACT In quantum physics all experimental information is discrete and stochastic. But the values of physical quantities are considered to depict definite properties of the physical world. Thus physical quantities should be identified with mathematical variables which are derived from the experimental data, but which exhibit as little randomness as possible. We look for such variables in two examples by investigating how it is possible to arrive at a value of a physical quantity from intrinsically stochastic data. With the aid of standard probability calculus and elementary information theory, we are necessarily led to the quantum theoretical phases and state vectors as the first candidates for physical quantities.