Solar cell design with over 50 percent energy-conversion efficiency

April 23, 2017

Solar cells convert the sun's energy into electricity by converting photons into electrons. A new solar cell design could raise the energy conversion efficiency to over 50% by absorbing the spectral components of longer wavelengths that are usually lost during transmission through the cell.

These findings were published on April 6 in the online edition of Nature Communications.

This research was carried out by a team led by Professor KITA Takashi and Project Assistant Professor ASAHI Shigeo at the Kobe University Graduate School of Engineering.

In theory, 30% energy-conversion efficiency is the upper limit for traditional single-junction solar cells, as most of the solar energy that strikes the cell passes through without being absorbed, or becomes heat energy instead. Experiments have been taking place around the world to create various solar cell designs that can lift these limitations on conversion efficiency and reduce the loss of energy. The current world record is at 46% percent for a 4-junction solar cell. If the energy-conversion efficiency of solar cells surpasses 50%, it would have a big impact on the cost of producing electricity.

In order to reduce these large energy losses and raise efficiency, Professor Kita's research team used two small photons from the energy transmitted through a single-junction solar cell containing a hetero-interface formed from semiconductors with different bandgaps. Using the photons, they developed a new solar cell structure for generating photocurrents. As well as demonstrating theoretical results of up to 63% conversion efficiency, it experimentally achieved up-conversion based on two photons, a mechanism unique to this solar cell. The reduction in energy loss demonstrated by this experiment is over 100 times more effective compared to previous methods that used intermediate bands.

The team will continue to design solar cells, and assess their performance based on conversion efficiency, working towards a highly efficient solar cell for low-cost energy production.

Kobe University

Related Solar Cell Articles from Brightsurf:

Theoretically, two layers are better than one for solar-cell efficiency
Solar cells have come a long way, but inexpensive, thin film solar cells are still far behind more expensive, crystalline solar cells in efficiency.

USTC made breakthrough in the Sb2(S,Se)3 solar cell efficiency
USTC developed a hydrothermal deposition method for the synthesis of antimony selenosulfide for solar cell applications.

Oxygen breathes new life into solar cell research
Scientists in Australia and the United States have been able to 'upconvert' low energy light into high energy light, which can be captured by solar cells, in a new way, with oxygen the surprise secret ingredient.

Merging solar cell and liquid battery produces long-lasting solar storage
Combining liquid chemical battery technology with perovskite solar cells has led to a new record in solar energy conversion within a single device.

Merging solar cell and liquid battery produces efficient, long-lasting solar storage
Chemists at the University of Wisconsin-Madison and their collaborators have created a highly efficient and long-lasting solar flow battery, a way to generate, store and redeliver renewable electricity from the sun in one device.

Windows will soon generate electricity, following solar cell breakthrough
Semi-transparent solar cells that can be incorporated into window glass are a 'game-changer' that could transform architecture, urban planning and electricity generation, Australian scientists say in a paper in Nano Energy.

Ultrathin organic solar cell is both efficient and durable
Scientists have succeeded in creating an ultrathin organic solar cell that is both highly efficient and durable.

Layered solar cell technology boosts efficiency, affordability
Researchers from CU Boulder have created a low-cost solar cell with one of the highest power-conversion efficiencies to date, by layering cells and using a unique combination of elements.

Anti-solar cells: A photovoltaic cell that works at night
What if solar cells worked at night? That's no joke, according to Jeremy Munday, professor in the Department of Electrical and Computer Engineering at UC Davis.

Promising discovery could lead to a better, cheaper solar cell
McGill University researchers have gained tantalizing new insights into the properties of perovskites, one of the world's most promising materials in the quest to produce a more efficient, robust and cheaper solar cell.

Read More: Solar Cell News and Solar Cell Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to