Assertion (A): Si and GaAs are the preferred | vedclass

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(A) The energy band gap of $Si$ is approximately $1.14 \ eV$ and for $GaAs$ it is $1.42 \ eV$.Solar cells are designed to absorb photons from the sola

Vedclass · Accepted Answer

$(A)$ is correct but $(R)$ is incorrect.

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(A) The energy band gap of $Si$ is approximately $1.14 \ eV$ and for $GaAs$ it is $1.42 \ eV$.Solar cells are designed to absorb photons from the solar spectrum. The solar radiation spectrum has a peak intensity around $1.5 \ eV$ to $2.0 \ eV$.For a material to be an efficient solar cell, its band gap should be close to the energy range of the maximum solar irradiance (typically $1.0 \ eV$ to $1.8 \ eV$).Since the band gaps of $Si$ $(1.14 \ eV)$ and $GaAs$ $(1.42 \ eV)$ fall within this optimal range, they are preferred materials.The reason $(R)$ states that the band gaps are 'much below' the energy level of maximum solar irradiance, which is incorrect because they are actually very close to the optimal range.Therefore, the assertion $(A)$ is correct, but the reason $(R)$ is incorrect.

Assertion $(A)$: $Si$ and $GaAs$ are the preferred materials for solar cells.
Reason $(R)$: Both these materials have energy band gaps much below the energy level corresponding to the maximum solar irradiance in the solar spectrum.

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Assertion $(A)$: $Si$ and $GaAs$ are the preferred materials for solar cells.Reason $(R)$: Both these materials have energy band gaps much below the energy level corresponding to the maximum solar irradiance in the solar spectrum.