Herein, we report polybenzodioxane polymer (PIM-1), a multifunctional n-type emitter with strong green luminescence, and its suitability as an electron transport layer for OLEDs devices. The BrunauerEmmett-Teller (BET) test and photo-electrical properties of as-synthesized PIM-1 confirm the presence of large microporosity and excellent electron mobility. The photoluminescence (PL) spectroscopy shows the intense green emission at 515 nm upon 332 nm excitation wavelength. Moreover, the Hall effect study reveals the negative Hall resistivity, which indicates that PIM-1 possesses n-type semiconductor . Additionally, the electron mobility is found to be 4.4 Â 10 À6 cm 2 V À1 s À1 . Hence, these results demonstrate that PIM-1 could be an ultimate choice as an n-type emitter for the next generation of advanced electronic devices.
The energy transfer process between surface plasmons and excitons was studied by varying the filling fraction of gold (Au) nano-clusters (NCs) and by placing a spacer of different thickness between Au NC and organic semiconductor layer. The intensity enhancement has occurred for 10%-50% filling fractions and 4-14 nm spacer thicknesses. Energy transfer mechanism was found to switch from Forster type to surface type by increase in filling fraction. Transverse electric field for Au NCs was simulated and we observed that for filling fraction <30%, Au NCs behave like 1-dimensional dipole and for >60%, they behave like 2-dimensional dipoles.
Effect of doping of 8-hydroxyquinolinatolithium (Liq) on the electron transport properties of tris(8-hydroxyquinolinato)aluminum (Alq 3 ) has been investigated as a function of temperature and doping concentration by fabricating electron only devices. It has been observed that current density in the devices increases with the doping of Liq up to a doping concentration of 33 wt. % and then decreases. Current density-voltage (J-V) characteristics of 0, 15, and 33 wt. % Liq doped Alq 3 devices were found to be bulk limited and analyzed on the basis of trap charge limited conduction model. The J-V characteristics of 50 and 100 wt. % Liq doped Alq 3 devices were found to be injection limited and were analyzed using the Fowler-Nordheim model. The increase in current density with doping up to 33 wt. % was found to be due to an increase in electron mobility upon doping, whereas the decrease in current density above 33 wt. % was due to the switching of transport mechanism from bulk limited to injection limited type due to an increase in barrier height. Electron mobility and variance of energy distribution have been measured by using transient electroluminescence technique to support our analysis. Electron mobility for pure Alq 3 was found to be 1 Â 10 À6 cm 2 /V s, which increased to 3 Â 10 À5 cm 2 /V s upon doping with 33 wt. % Liq. The measured values of variance were 95, 87.5, 80, 72, and 65 meV for 0, 15, 33, 50, and 100 wt. % Liq doped Alq 3 respectively. The increase in electron mobility upon doping has been attributed to a decrease in energetic disorder upon doping as evidenced by the decrease in variance. The increase in barrier height for the higher doping concentration was due to the disorder related correction r 2 /2kT in the barrier height, which decreases with the increase in doping concentration.
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