Light-energy conversion device

Figure 12-2 Chemical structure and conceptual design of a convergent and directional light-energy conversion device. The bottom diagram shows the variation of excited-state energy as a function of position within the dendrimer hierarchy.

The energy conversion devices should preferably be storage devices, for use when light incidence is absent (i.e., at night). 

Another important characteristic of semiconductors is their optical absorption properties. The optical properties of semiconductors are crucial to their uses as photovoltaic energy conversion devices, photonic detectors, light-emitting diodes, solid state lasers, and optical switches see Semiconductor Interfaces). Some semiconductors absorb both visible and ultraviolet light, while others only absorb photons in the... 

Recall the shorthand notation used for benzene.) (a) What is the hybridization at the N atom in each of the substances (b) How many unhybridized atomic orbitals are there on the N and the C atoms in each of the substances (c) Predict the N — N — C angles in each of the substances, (d) Azobenzene is said to have greater delocalization of its Tr electrons than hy-drazobenzene. Discuss this statement in light of your answers to (a) and (b). (e) All the atoms of azobenzene lie in one plane, whereas those of hydrazobenzene do not. Is this observation consistent with the statement in part (d) (f) Azobenzene is an intense red-orange color, whereas hydrazobenzene is nearly colorless. Which molecule would be a better one to use in a solar energy conversion device (See the Chemistry Put to Work box for more information about solar cells.)... 

In the 1970s, the idea of photoelectrochemical cells for light to electrical and/or chemical energy conversion attracted scientists in various fields as a novel energy conversion device. Photoetching has been widely used to modify the semiconductor surface and consequently improve the cell efficiency [1, 2]. This improvement is attributed to several effects, such as a decrease in reflection losses (3), an increase in effective electrode area, a removal of surface defects acting as recombination centers [4-7], and change in the chemical composition of surface [8, 9j. 

Siores et al. (2010) have developed a fibre stmcture that can be used to convert mechanical and light energy into electrical energy. The hybrid energy conversion device consists of a piezoelectric polymeric structure coated with a photovoltaic system. The fibre is claimed to be flexible enough to be converted into textiles for energy harvesting. 

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