The preparation of doped graphene by this method requires the preparation of graphene oxide film. The preparation of graphene oxide is simpler and less expensive than that of graphene, and the preparation conditions do not require harsh conditions such as high temperature, and can be carried out at room temperature (of course, in the end, the prepared graphene oxide solution should be baked into a film at a slightly higher temperature, but the temperature is far less than that of graphene). When there is a graphene oxide film (we still take nitrogen-doped graphene as an example), the film and some nitrogen-containing compounds such as urea or melamine can be put into the corresponding reactor for high-temperature reaction. Since nitrogen-containing compounds will decompose many nitrogen-containing gases (such as ammonia, etc.) at high temperatures, they will have corresponding organic reactions with oxygen-containing functional groups (such as carboxyl groups, etc.) on the surface of graphene oxide to generate nitrogen-containing functional groups, so as to achieve the purpose of doping.

From this process, we can find that the process of this method is more complex than the previous two, but the biggest advantage is that the cost is lower. However, the biggest disadvantage of this method is that the doped graphene prepared in the end may contain impurity atoms that we do not want, such as oxygen atoms, etc., which is also the most fatal disadvantage of this method. The incorporation of these non-ideal impurities will inevitably affect the characteristics of the entire ideal doped graphene, which will bring many unknown difficulties to subsequent experiments. So it's still the same saying, "you get what you pay for". However, for some experimental accuracy requirements that are not particularly high and the funds are not very sufficient, this method can be appropriately considered.

Nowadays, there are more and more research and applications on doped graphene, among which many scientists have prepared various MOS tubes, photocells, etc. with the prepared doped graphene as the core material, and have conducted detailed research on their characteristics, and have also found many unique advantages. In this way, doped graphene has potential development and application in the field of materials and electronics, and may even change our lives in some aspects, even a little bit, it will be a great success.