New Signal Amplification, Cycling Excitation Process (CEP), Opens Up New Generation of Electronic Systems

Researchers from the University of California, San Diego has discovered a new signal amplification process called CEP or Cycling Excitation Process.

CEP can amplify photocurrents at a much lower voltage and noise than current existing methods.

Current semiconductor devices use photodetectors and low-noise electronic amplifiers to convert optical signals into electronic signals with amplification to enable information detection and processing. The UC San Diego team found a more efficient method by modifying the p/n junction, a boundary or interface between two types of semiconductor material inside a single crystal of semiconductor.

CEP can be used in devices and semiconductors which opens up a myriad of possibilities in the semiconductor industry; communication and imaging devices with superior sensitivity can be produced at a low cost.

New types of transistors and circuits can also be produced that furthers the scope of applications past optical detection.

MIT Solar Thermophotovoltaic System Increase Solar Cell Efficiency Up To 80%

Researchers at MIT have developed a solar cell that is much more efficient than current solar photovoltaic cells. Using nanotechnology and material technology, the new cell captures a broader spectrum of light compared to a regular solar cell and transforms these into energy. This development can increase solar power output past current efficiency limits.

By adding an absorber-emitter device between photovoltaic cell and sunlight, the other undetected wavelengths of light is also converted into electricity through heat. Carbon nanotubes and photonic crystals are used as material for the absorber-emitter device.

Photovoltaic cells are solid state electrical devices that convert the energy of light directly into electricity by the photovoltaic effect (using light to convert to energy).

The present maximum theoretical efficiency of a solar cell is 33.70%. This is known as the Shockley-Queisser limit. With the new developed solar cell, the researchers believe once the technology is fully develop, it can break the limit and hit an efficiency rating of well over 80%.

Nanowire Based Solar Cell Increases Shockley-Queisser Efficiency Limit

The figure shows that the sun's rays are drawn into a nanowire, which stands on a substrate. At a given wavelength the sunlight is concentrated up to 15 times. Consequently, there is great potential in using nanowires in the development of future solar cells.
Credit: Niels Bohr Institute

The development of a nanowire based solar cell that increases sunlight concentration to a a factor of 15 raises the standard efficiency limit of solar cells known as the Shockley-Queisser limit.

One of the most popular and common source of renewable and sustainable energy is the Sun. Solar energy is not dependent on weather conditions such as wind power or need to be near a power source such as geothermal or hydroelectric energy producers.

Solar energy is produced by solar panels or solar cells. These cells, also known as photovoltaic cells, convert sunlight to electrical energy.

The focus on solar cell technology is raising the efficiency of the solar cell to convert solar energy to electrical energy. In solar cell production, the value that is used to gauge the efficiency of the solar cell is the Shockley-Quesser limit. This limit refers to the maximum theoretical efficiency of a solar cell using a p-n junction to collect power from the cell.

A p-n junction refers to the boundary of two semiconductors; the p-type and the n-type. The p-type semiconductor contains excess holes while the n-type contains excess free electrons.

The Shockley-Queisser limit puts the maximum solar cell efficiency at around 33.7%. This means that at most, only 33.7% of sunlight can be converted into elecrical energy. Currently, silicon based photovoltaic cells have an efficiency of 22%.

Nanotechnology Research Develops New Photovoltaic Process Using Gold Nanorods

Researchers in Photovoltaic technology have developed a new method in converting sunlight into electrical energy using gold nanorods.

Research into photovoltaic energy (converting solar rays into electrical energy) has benefited a lot from materials technology and nanotechnology. The main process of a photovoltaic cell or solar cell is using the photons from the sun's rays to basically move electrons around to generate electricity.

At this level, nanotechnology can help push the methods to even higher ground since the technology deals with properties and processes at the molecular and even atomic scale. One application that nanotechnology can contribute to photovoltaic research is the nanorod.

Nanorods are nanostructures that are elongated and shaped like a hotdog. These can range in size from 1 nanometer (nm) to 100nm. These structures interact with light, electricity, and magnetic fields that makes it a very good candidate for semiconductors and photovoltaic applications.

Graphene Shows Potential To Be Efficient Photovoltaic Material In Light Detection and Energy Harvest

Graphene research has shown that the material can be used in the development of efficient solar photovoltaic cells.

Much has been written and discussed about graphene. It has opened up a whole litany of advanced applications that it has been described as "The Wonder Material".

One particular property of graphene that many scientists have been focusing on is how electrons behave and interact with graphene. Graphene, being only one atom thick, allows electron to move much more freely along its surface. The electrons travel through the graphene sheet as if they carry no mass, as fast as just one hundredth that of the speed of light. This makes graphene a great conductor, better than even copper.

Also, since graphene is just one atom thick, diodes, transistors, and other electronic components can be developed on a single-layered device architecture. By using nano-scale electronic channels and tailoring the geometrical symmetry, devices can be operated on at very high speeds of up to 1.5 Terahertz (1,500 GHz). This allows for the development of high speed electronics for various applications and devices.

Researchers have discovered a new property of graphene that allows it to convert a single absorbed photon into multiple electrons. This could open up research into the development of efficient solar cells.