“…Figure a shows a mapping diagram of the temperature-dependent photoluminescence (PL) spectrum of a diamond produced by the high-temperature and high-pressure (HPHT) method excited by a 193 nm deep-UV laser. − (See the Supporting Information for Materials and Methods and Figures S1–S3.) As the temperature changes from 10 to 290 K, the PL spectrum of HPHT diamond exhibits phonon-assisted luminescence characteristics of the FE and EHL, including the phonon replicas of the FE, that is, FE TA , FE TO , FE LO , FE TO+OΓ , and FE TO+2OΓ , and the phonon replicas of the EHL, that is, EHL TO and EHL TO+OΓ , which are similar to those reported in previous research. ,, It can also be seen from Figure a that the temperature dependences of these emission peaks of FE-and EHL-related phonon replicas are quite different as the temperature rises (see Figure for the specific change process): The emission intensity of the former one increases first and then decreases with a blue-shifted trend shown by the peak position (see Figure S4 for the peak position change of FE TO and FE TO+OΓ excitonic peaks as the temperature rises) (i.e., it moves to higher-energy zone), whereas for the latter one, the emission intensity gradually decreases with the peak position, displaying a red-shifted trend (i.e., it moves to lower-energy zone).…”