Challenges are not uncommon in developing new technologies. The current topics that are most in the publications are medical nanotechnology and the so-called two dimensional materials. Electronics constructed using the 2-D materials is being experimented with, but there have not been published results of significant advancements. Fuel cells with 2-D materials appears to currently be a topic of strong interest with most of the focus on graphene. The term 2-D materials is employed as being more inclusive of the current research, which is evaluating other materials with superior properties. A critical objective of the development of 2-D materials is creating a low cost process for producing large quantities of defect free material.
Medical: The Center for Responsible Nanotechnology [Ref. 1] has a long list of potential medical applications that when/if developed can be of significant benefit. If you want to do a comparison of where development is today, AZO nano [Ref. 2] has a 2005 reference article on “current” concepts. An issue with developments in the medical field is that the process for developing a product that can be used in humans requires a regulatory process that can significantly exceed seven years. In certain cases, the EU has streamlined processes. There are some cancer drugs that are available in the EU. Consequently, people need to explore treatments available around the world.
Graphene Electronics: The topic of graphene has been covered in a number of blogs. As has been discussed, the major issue is the manufacture of inexpensive, defect free material. There are efforts to create electronic systems that operate in realms that are unachievable without nanotechnology. There is a report from the Max Planck Institute [Ref. 3] on the potential for terahertz operation due to picosecond electrical conduction. There is a presentation from C. Y. Sung of IBM [Ref. 4] on the development of graphene nanoelectronics. Recent development sin “ribbons” of graphene [Ref. 5] discusses a new approach to creating graphene for transistors. The fundamental problem is that the current methods of creating transistors (semiconductor circuits) is that they are manufactured at a rate of billions per minute. Anything that will be employed to surpass the existing circuitry must have the high volume manufacturing capability that exists in semiconductors today. That capability has not been proven yet.
Fuel Cells: Researchers are developing means of adding impurities into 2-D structures that can provide additional storage capability benefits [Ref. 6]. An overview of nanotechnology in Fuel Cells [Ref. 7] provides an overview of the fuel cell technology improvements. Graphene may be a replacement for platinum. Graphene and cobalt are another possibility. A web search will turn up many possibilities for additional materials. The issue for application still comes down to being able to manufacture the nanomaterials is sufficient quantities at a reasonable cost.
The long term view is that there is still much development that needs to be accomplished before we are able to reap the benefits of nanomaterials.