Glitter sized solar cells. 1oo times more efficient than conventional solar cells

Solar cell is a device that converts the energy of sunlight directly into electricity by the photovoltaic effect. The main drawback of conventional solar cells are the poor energy conversion efficiency. A solar cell’s energy conversion efficiency (?, “eta”), is the percentage of power converted (from absorbed light to electrical energy) and collected, when a solar cell is connected to an electrical circuit. The challenge of increasing the photovoltaic efficiency is thus of great interest, both from the academic and economic points of view. Many groups have published papers claiming possibility of high efficiencies after conducting optical measurements under many hypothetical conditions. The University of New South Wales has achieved 25% efficiency on mono-crystalline silicon in the lab, which was the highest reported solar cell efficiency.

Now the scientists of Sandia Nations laboratories, US has claimed the development of a new tiny glitter-sized photovoltaic cells that could revolutionize the way solar energy is collected and used.

Technology used

The cells are fabricated using microelectronic and Micro Electro Mechanical systems (MEMS) techniques common to today’s electronic foundries.

The solar particles, fabricated of crystalline silicon, hold the potential for a variety of new applications. They are expected eventually to be less expensive and have greater efficiencies than current photovoltaic collectors that are pieced together with 6-inch- square solar wafers.

Each cell is formed on silicon wafers, etched and then released inexpensively in hexagonal shapes, with electrical contacts prefabricated on each piece, by borrowing techniques from integrated circuits and MEMS.

Advantages  claimed by the lab

Extremely thin structure as compared to conventional Solar cells. This cell is 10 times thinner than a  6-inch-by-6-inch brick-sized cells.

Significant reduction in manufacturing and installation costs compared with current photo voltaic  techniques.

Electricity presently can be harvested from the Sandia-created cells with 14.9 percent efficiency. Off-the-shelf commercial modules range from 13 to 20 percent efficient.

Uses 100 times less Silicon to produce the same electricity as compared to conventional solar cells.

The shade tolerance of this units to overhead obstructions is better than conventional PV panel. The portions of this cell not in shade will keep sending out electricity where a partially shaded conventional panel may turn off entirely.

High-voltage output is possible directly from the modules because of the large number of cells in the array. This should reduce costs associated with wiring, due to reduced resistive losses at higher voltages.

Applications

The tiny cells could turn a person into a walking solar battery charger if they were fastened to flexible substrates molded around unusual shapes, such as clothing.

Satellites and remote sensing.

Fast and efficient recharge of the batteries used in electronic devices.

Can be used to make  rooftops of homes and warehouses to harvest solar energy, which is an effective alternative of conventional electricity sources.