Confined Hot Carrier Cooling Via Excited‐State Energy Gap Engineering in Graphyne Carbon Allotropes

Engineering excited‐state energy gap as an efficient route to manipulate hot carrier dynamics can induce various functional applications, including photon harvest, operations, and energy conversion. However, it remains a challenge to realize atomic‐scale excited‐state energy gap engineering in periodic material system compared to molecular system. Here, we establish atomic‐scale excited‐state energy gap engineering for confined hot carrier cooling in the α‐graphyne family structural paradigm via sp hybrid carbon motifs design. We reveal that the positions of the excited‐state energy gap and the peak in electronic density of states governed by sp hybrid carbon concentration can serve as knobs for controlling the electron–phonon coupling behavior based on first‐principles calculations. This strategy demonstrates that hot carrier can be confined at the top of the excited‐state energy gap with tunable energy levels for a long period of time and their relaxation time constants are prolonged by 2–3 orders of magnitude via ab initio nonadiabatic molecular dynamics in momentum space. Our findings provide insights into atomic‐level excited‐state energy gap engineering for manipulating hot carrier dynamics, which is crucial for the material design of quantum information and energy devices.