Novel wavelength shifters to improve sensitivity of vacuum photodetectors to Cherenkov light

We describe novel wavelength shifters (WLS) to improve sensitivity of photodetectors to Cherenkov light. Due to inconsistency of Cherenkov radiation spectrum and photodetectors spectral sensitivities, a large share of Cherenkov photons are left undetected. Different types of WLS have been used for more than 40 years to solve this problem. In this paper we present novel WLS developed for astroparticle physics Cherenkov experiments. The main parameters (emission and absorption spectra, decay time etc.) of the shifters are shown. We also present results of in-situ tests of the developed shifters in the experiment.