Wave absorbers are basic blocks which can be designed using 2D materials. There is a long listed researches in this topic. For instance you can see:

Tunable ultra-wideband terahertz absorber based on graphene disks and ribbons

S Biabanifard, M Biabanifard, S Asgari, S Asadi, CE Mustapha

Optics Communications 427, 418-425

Hi Swadhin Jena

I believe there are a lot of potential application areas for 2D materials. At the frontier of the research field, you could try looking at defect engineering in 2D materials e.g graphene, MoS2 for room temperature single photon emission. This I believe have a lot of relevance for future quantum devices. Best of luck.