The electronic and optical properties of graphene and other 2D materials, such as transition metal dichalcogenides TMDCs and hexagonal boron nitride h-BN , are highly sensitive to changes in temperature and doping concentration. Here, we will discuss the effects of temperature and doping on the electronic and optical properties of these materials.1. Temperature:a Electronic properties: As temperature increases, the thermal energy of the electrons in the material also increases. This leads to an increase in the electron scattering rate, which in turn results in a decrease in the carrier mobility. Consequently, the electrical conductivity of the material decreases with increasing temperature. In semiconducting 2D materials, the bandgap can also be affected by temperature, typically decreasing with increasing temperature due to thermal expansion and electron-phonon interactions.b Optical properties: The optical properties of 2D materials are also influenced by temperature. The absorption and emission spectra of these materials can shift to lower energies redshift as temperature increases, due to the aforementioned decrease in bandgap. Additionally, the intensity of photoluminescence can decrease with increasing temperature, as higher temperatures promote non-radiative recombination processes.2. Doping concentration:a Electronic properties: Doping is the process of introducing impurities or defects into a material to modulate its electronic properties. In graphene, doping can be achieved through chemical functionalization or by applying an external electric field gate voltage . Doping can either increase the number of charge carriers n-type doping or decrease the number of charge carriers p-type doping . As a result, the electrical conductivity of the material can be tuned by controlling the doping concentration. In semiconducting 2D materials, doping can also modify the band structure, effectively changing the material's electronic properties.b Optical properties: Doping can significantly impact the optical properties of 2D materials. For example, in TMDCs, doping can induce a transition from an indirect bandgap to a direct bandgap, which leads to enhanced photoluminescence and absorption. Moreover, doping can also affect the exciton binding energy and the exciton recombination dynamics, which in turn influence the material's optical response.In summary, the electronic and optical properties of graphene and other 2D materials are highly sensitive to changes in temperature and doping concentration. Understanding these dependencies is crucial for the development of novel devices and applications based on these materials, such as sensors, transistors, and optoelectronic devices.