Efficient Emission Facilitated by Multiple Energy Level Transitions in Uniform Graphitic Carbon Nitride Films Deposited by Thermal Vapor Condensation

Graphitic carbon nitride (g‐CN) films are important components of optoelectronic devices, but current techniques for their production, such as drop casting and spin coating, fail to deliver uniform and pinhole‐free g‐CN films on solid substrates. Here, versatile, cost‐effective, and large‐area growth of uniform and pinhole‐free g‐CN films is achieved by using a thermal vapor condensation method under atmospheric pressure. A comparison of the X‐ray diffraction and Fourier transform infrared data with the calculated infrared spectrum confirmed the graphitic build‐up of films composed of tri‐s‐triazine units. These g‐CN films possess multiple active energy states including π*, π, and lone‐pair states, which facilitate their efficient (6 % quantum yield in the solid state) photoluminescence, as confirmed by both experimental measurements and theoretical calculations.