Unlocking the chemistry of graphene: The impact of charge carrier concentration on molecular adsorption on graphene

Both intentional and unintentional doping of graphene is a common occurrence, as its carrier concentration can be modulated through various mechanisms. While extensively explored in electronics for achieving desirable conductivity, other aspects of doping remain largely untapped, presenting opportunities for further innovation. This study demonstrates that carrier concentration serves as a powerful and selective tool for modulating the interaction between molecular adsorbates and graphene. The effects are tunable and evident for both n-type and p-type doping, with low-to-medium modulation at doping levels of ± 10 12 e /cm 2 , and substantial enhancements, with interaction strength increases exceeding 150% and hundreds of meV, at doping levels of ± 10 13 e /cm 2 . These effects are also molecule-specific, with significant enhancements for species such as water (H 2 O), ammonia (NH 3 ), and aluminum chloride (AlCl 3 ), while having minimal impact on species like hydrogen (H 2 ). This finding not only elucidates the fundamental chemical behavior of graphene but also provides a versatile method to tailor its surface chemistry for applications in sensors, catalysis, and electronic devices. The insights from this research pave the way for advanced material design strategies, leveraging the tunable nature of graphene’s properties to optimize its interaction with various molecular species. • Carrier concentration is a powerful tool for modulating graphene’s reactivity. • The effects are tunable and evident for both n-type and p-type doping. • Low-to-medium modulation occurs at doping levels of ±10 12 e/cm 2 . • Substantial modulation occurs at doping levels of ±10 13 e/cm 2 . • These effects are molecule-specific, showing modulation between +3% and +171%.