The correct option is (c).
Explanation
Graphene is an allotrope of carbon consisting of a single layer of atoms arranged in a two-dimensional honeycomb lattice. It is the basic structural element of other allotropes, including graphite, charcoal, carbon nanotubes, and fullerenes.
Statement-wise Analysis:
- Statement 1 is Correct: Graphene is widely regarded as a two-dimensional material because it is only one atom thick. It possesses exceptionally high electrical conductivity (higher than copper) and thermal conductivity due to its unique electronic structure.
- Statement 2 is Correct: Being one atom thick, it is the thinnest material known. Despite its thinness, it is the strongest material ever tested, estimated to be about 200 times stronger than steel by weight.
- Statement 3 is Incorrect: Graphene is entirely made of carbon, not silicon. While the second part of the statement regarding high optical transparency (absorbing only about 2.3% of light) is true, the claim that it is made of silicon makes the statement factually wrong.
- Statement 4 is Correct: Due to its combination of high optical transparency and electrical conductivity, graphene is an ideal candidate to replace Indium Tin Oxide (ITO) as transparent conducting electrodes. These are essential components in touch screens, Liquid Crystal Displays (LCDs), and Organic Light-Emitting Diodes (OLEDs).
Key Takeaway:
Graphene is a carbon-based, single-atom-thick (2D) nanomaterial known for being the strongest material tested, highly conductive, and optically transparent, making it suitable for next-generation electronics.