Organic electronics is a field in which organic materials are used to manufacture electronic devices that are very flexible and can be printed easily. Organic solar cells, also known as plastic solar cells, use polymers to produce electricity from sunlight.
Having control over these organic solar cells after they absorb light is the biggest constraint to their usage. Due to this, a large amount of energy absorbed is wasted and thus the efficiency of these solar cells decreases. There is therefore a requirement for techniques or materials that would help to control the solar cells after they absorb solar energy, thereby making them more cost effective.
Addressing this need, a group of researchers from University of Toronto has revealed that control over these organic solar cells is now possible even at normal conditions or room temperature. These organic solar cells can be controlled by the use of quantum effects even after they have absorbed solar energy.
The movement of energy in these solar cells is due to the quantum mechanical mechanism and not a random movement at room temperature. Polymer solar cells are lightweight, flexible and disposable, and their fabrication is also cost-effective. It is anticipated that controlling these polymer solar cells using the quantum effects will pave the way for producing cheap and more efficient solar cells, which could be used in producing electricity.
In the research study, the team in Toronto used conjugated polymers, which are the most effective material used in the production of solar power. Conjugated polymers are very long organic molecules that bear the same property as that of a semiconductor and can be employed in transistors and LEDs.
The long chains in these polymers repeat the same molecular patterns and can be manipulated to mimic the properties of traditional silicon-based semiconductors, while retaining important organic characteristics. When polymers are exposed to light, energy is produced and moves along the polymer chains even before it is converted into electrical charges.
From the chains, the energy reaches the molecules and eventually leaves the cells. The transmission path of this energy is still unclear and as a result, it has become difficult to achieve maximum efficiency.
The movement of energy in these molecules is due to the quantum mechanical mechanism at room temperature. Ultrashot lasers were used for triggering the atoms in the molecules into a quantum mechanical state, where the atoms are in the ground state and at the same time at an energy level to absorb a photon, known as quantum coherence.
The chemical framework of these molecules forms the basis for the quantum coherent energy transfer. In the absence of the chemical framework of these molecules, the energy is displaced. Hence, the chemical properties of these molecules play a key role in having a check on the movement of energy, and also to guide the ultrafast migration of energy using quantum coherence.
Since these quantum effects occur at room temperature, this mechanism can be used in constructing quantum computers, where ultra-low temperature is required to retain the quantum effects. These properties make them perfect to be used as a building block for quantum computers, while the new discovery has endowed that quantum effects can be used even at room temperature.
For more information contact Patrick Cairns, Frost & Sullivan, +27 (0)21 680 3274, [email protected], www.frost.com
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