Which of the following is not used in making solar cells?
2019
Which of the following is not used in making solar cells?
- A.
Silicon
- B.
Platinum
- C.
Gallium
- D.
Germanium
- E.
Cadmium
Show answer & explanation
Correct answer: B
A solar (photovoltaic) cell converts sunlight into electricity using a semiconductor material whose band gap allows incoming photons to free electrons and create a controllable electric current. The mainstream solar-cell technologies deployed at commercial and industrial scale are built from a known set of such semiconductors.
Material | Role in solar-cell technology |
|---|---|
Silicon | Semiconductor base of crystalline-silicon photovoltaic cells, which make up the large majority of commercial solar panels. |
Gallium | Combines with arsenic to form gallium arsenide (GaAs), used in high-efficiency and multi-junction space-grade solar cells. |
Germanium | Forms the bottom junction of III-V multi-junction space solar cells, because its narrow band gap absorbs the lower-energy part of the solar spectrum. |
Cadmium | Combines with tellurium to form cadmium telluride (CdTe), the semiconductor of a major commercial thin-film solar-panel technology. |
Platinum | Not a semiconductor; forms no part of the light-absorbing layer in crystalline-silicon, GaAs/Ge multi-junction, or CdTe cells. |
Silicon, gallium, germanium, and cadmium each map onto one of these mainstream solar-cell technologies (crystalline-silicon, GaAs/Ge multi-junction, and CdTe thin-film cells). Platinum plays no role in any of them; its only documented solar-related use is as an electrode-catalyst coating in dye-sensitized solar cells (DSSCs), a different cell architecture that has seen limited/niche commercial use rather than mainstream deployment. This exact item is a previous-year question from Bihar STET (2019, Computer Science paper), whose published official answer key keys Platinum as the answer. Given that platinum has no role in the mainstream technologies this question targets, and the official key confirms it, Platinum is the best-supported answer among the materials offered - though a stricter reading acknowledging platinum's niche DSSC role shows the stem's wording is not perfectly airtight.