To find out the deuteration effect on the molecular vibrations, Fourier transform infrared (FT-IR) spectra were simulated in Fig. and. As anticipated, the distinctive band attributed to the C-H stretching mode at 3203 cm -1 gradually decreased and a novel absorption peak for the C-D stretching mode at 2376 cm -1 emerged in the spectra of D-SiCzCz and D-SiTrzCz2. Similar variations were also observed in the experimental infrared spectra as shown in Supplementary Fig. , where the high energy absorption bands at 3046 and 3047 cm -1 were significantly suppressed while new absorption bands at 2264 and 2266 cm -1 exhibited pronounced distinctions, substantiating the reduction of molecular energy subsequent to deuteration. Considering that the unchanged molecular skeleton and the vibrational degrees of freedom, these changes in FT-IR absorption intensity can be attributed to the suppression of high frequency vibrations after deuteration. Furthermore, the zero-point energy (ZPE) values were also calculated before and after deuteration , with a notable reduction from 1782.77 to 1653.37 KJ/mol for donors and from 1904.84 to 1766.03 KJ/mol for acceptors. The differences are mainly observed in the C-D bonds, which exhibited lower frequency vibrations, while the vibrations of the C-C and C-N bonds remains at a base value (Fig. and). The combination of ZPE values and FT-IR results demonstrated that deuterated materials should exhibit a relatively lower population at high vibrational energy levels, which is advantageous for the intrinsic stability of the host materials under excited states. In order to have a more intuitive understanding on the effect of deuteration on structural stability , we also calculated the bond dissociation energies (BDEs) in positive, negative and neutral states for electron donors and acceptors, respectively (Supplementary Table ). The BDE values of the C-D bonds are significantly higher than those of the C-H bonds in both the neutral and ionic states, manifesting the isotope effect on the intrinsic structural stability. The enhancement of bond energy in negative state (BDE(-)) can effectively inhibit the reactivity of carbazoles at 3-and 6-position, thus providing a rigid environment to significantly reduce destructive deactivation of the excited states. Meanwhile, deuterium substitutions also induce some improvements in the BDE values of the fragile C-N and C-C bonds, further illustrating the promotional effect of deuteration on stability enhancement. It is therefore anticipated that the elevated degree of deuteration on both electron donors and acceptors can exert a more pronounced effect on the stability of exciplexes.