Understanding the Mechanisms of White Light Emission of a Tetradentate Pt Complex in Various Surrounding Environments

Abstract

For the great progress in panel display devices, it is necessary to have a thorough understanding of white organic light-emitting diodes (WOLEDs). In this work, we confirmed a reasonable mechanism of the white light emission with dual emission peaks in the studied compound; the mechanism is that the white emission could be formed with the 0−0 peak and the low-energy emission peak, where the latter is constituted by the highfrequency normal modes with larger Huang−Rhys factors. Moreover, in order to systematically understand the work performance in different surrounding environments, the emission spectra in solution, crystal phase, and amorphous phase were simulated. In view of the fact that the maximum emission wavelength of this complex corresponds to the 0−0 peak, the red-shifted emission from the solution to the crystal phase in experiment could be attributed to the smaller energy gap of the d−π* transition and the lower reorganization energy of the ground state (λ gs ) in the crystal phase. Additionally, our calculations indicate that the smaller energy gap of the π−π* transition and the smaller λ gs in the amorphous phase would cause the red-shifted emission from the crystal phase to the amorphous phase, where the smaller energy gap plays the primary role. In the meantime, it is found that vibronic couplings play a predominant role in photoluminescence efficiency changes caused by environmental effects. Our computational study will provide valuable information to the rational design of optical applications with white emission, which is meaningful to the future development of WOLEDs.

Efficient polymer light-emitting diodes (PLEDs) based on chiral [Pt(C^N)(N^O)] complexes with near-infrared (NIR) luminescence and circularly polarized (CP) light

“…Among the split two peaks (0-0 transitioned  em = 730 nm and 0-1 transitioned  em = 860 nm) relative to a different degree of vibrational coupling, the lower-energy emission peak is probably constituted by the high-frequency normal modes with larger Huang-Rhys factors. 21 Their phosphorescent properties show a structural profile: a short lifetime of 0.88 s for 1, and a significantly longer 1.02 s 2 or 0.96 s for 3 should result from the Br-facilitated intersystem-crossing. The electron-donating effect of two -tert-butyl groups should contribute to the shortest one (0.85 s) for the (S-L 4 ) --involved 4.…”

Solid-State Effect Induced Thermally Activated Delayed Fluorescence with Tunable Emission: A Multiscale Study

“…The polarizable continuum method (PCM) (as shown in Figure a) model is used to simulate the liquid environment. To investigate the photophysical properties of M1 in crystal and amorphous states, a combined quantum mechanics and molecular mechanics (QM/MM) method, which has been successfully used to study the photophysical properties of TADF molecules, − is adopted, and a two-layer ONIOM model is used as shown in Figure b,c. The initial configuration was built according to the crystal structure detected experimentally .…”

Photophysical properties of the triangular [Au(HNCOH)]3 complex and its dimer

“…An increased quantum yield has been attributed to small Franck-Condon factors in the past. 81 For the dimer, there are significant differences between the rate constants calculated using the CC2 and XMCQDPT2 transition energies. The IC and ISC rate constants from S 1 are larger at the XMCQDPT2 level, because the de-excitation energy of the S 1 state is smaller than obtained in the CC2 calculations.…”