Here we propose, for the first time, a solar cell characterized by a semiconductor transistor structure (n/p/n or p/n/p) where the base-emitter junction is made of a high-bandgap semiconductor and the collector is made of a low-bandgap semiconductor. We calculate its detailed-balance efficiency limit and prove that it is the same one than that of a double-junction solar cell. The practical impo...

this article exposes an analysis of the zoroastrian persian calendar in a 12th century hebrew book on the jewish calendar (sefer ha-‘ibbūr). the hebrew treatise was composed by the polymath abraham bar ḥiyya, probably in northern france. bar ḥiyya depicts the structure of the zoroastrian persian calendar, its months and some of its festivals. he then expounds on calendrical algorithms which ena...

We construct updated solar models with different sets of solar abundances, including the most recent determinations by Asplund et al. (2009). The latter work predicts a slightly larger solar metallicity compared to previous measurements by the same authors but significantly lower than the recommended value from a decade ago. The new solar models incorporate an updated equation of state and new ...

Abstract—Solar water heating is a thermodynamic process of heating water using sunlight with the help of solar water heater. Thus, solar water heater is a device used to harness solar energy. In this paper, a modified solar water heating system (MSWHS) has been proposed over flat plate collector (FPC) and Evacuated tube collector (ETC). The modifications include selection of materials other tha...

The current discussion about dwindling reserves of crude oil, rising fuel prices, global warming and supply disruption of natural gas has renewed interest in the provision of bioenergy and bio-based commodity products. There is a growing consensus that the 21st century will see a profound change in the resource base for industry and society, with less emphasis on fossil coal, oil and gas and mo...

Many thin film heterojunction solar cells contain an interface between the emitter and base which is a very high recombination region and which effectively prevents the passage of minority carriers. However, by utilizing proper design techniques which will be discussed here, the problem can be minimized; efficient thin film heterojunction solar cells can be fabricated, even though they contain ...

There is an increasing awareness about the need to achieve a more sustainable mobility, both among specialists and in public opinion, and about the opportunities given by renewable sources. In last years, increasing efforts are being spent towards the application of solar energy to electric and hybrid cars, also thanks to the advances in photovoltaic technology and to their growing diffusion fo...