Luminescence of the hydrogen bonded crystals

A complex investigation of the dynamics of electronic excitations in the hydrogen bonded crystals of potassium and ammonium dihydrophosphates—KH2PO4KH2PO4 (KDP) and NH4H2PO4NH4H2PO4 (ADP)—is performed by the means of the low-temperature time-resolved vacuum ultraviolet (VUV) optical luminescence spectroscopy with subnanosecond time resolution and with selective photoexcitation by synchrotron radiation. For KDP and ADP crystals, data on the kinetics of the photoluminescence (PL) decay, the time-resolved PL spectra (2–6.2 eV), and the time-resolved excitation PL spectra (4–24 eV) at 8 K were obtained. The intrinsic character of the PL of KDP (5.2 eV) and ADP (4.7 eV), which is caused by the radiative annihilation of self-trapped excitons (STEs), is ascertained. Possible channels of generation and decay of relaxed and unrelaxed electronic excitations in KDP and ADP crystals are discussed.