Insights on photophysical proprieties of DCM dye in PVK host matrix

Abstract

In this work, the photophysical proprieties of 4‐(dicyanomethylene)‐2‐methyl‐6‐(p‐dimethylaminostyryl)‐4H‐pyran (DCM) dye in the poly‐vinylcarbazole (PVK) matrix are analyzed with a particular attention to the energy transfer processes between the matrix and the dye. PVK films doped with weight percent varying from 1 to 8 wt% of DCM have been fabricated. The emission spectra are dominated by the presence of DCM and a strong red shift in the emission spectra of the blend has been observed as function of dye concentration. A quenching effect in the excitons lifetime increasing the concentration of the dopants has been observed. These two phenomena have been studied in terms of energy processes inside the blends. POLYM. COMPOS., 34:1500–1505, 2013. © 2013 Society of Plastics Engineers

The impact of 1 wt% of Ir(ppy) 3 on trapping sites and radiative recombination centres in PVK and PVK/PBD blend seen by thermoluminescence

“…The effect is caused by the interaction 37 of trapped carriers and randomly oriented high permanent dipoles of Ir(ppy) 3 . In addition, the 38 experiments of spectrally resolved TL (SRTL) provide evidence that the presence of the dopant creates 39 a new channel of energy transfer. Even at concentration of 1 wt% of Ir(ppy) 3 , these molecules act as 40 emission centres which effectively compete with other centres of radiative recombination present in 41 PVK and PVK/PBD systems.…”

“…6c with half-width about 80 nm [38]. Similar emission band with a 516 maximum at 530 nm was also recorded for PLEDs in which emis-517 sion layer was formed from a solution of PVK and Ir(ppy) 3 in 518 chlorobenzene [39]. 519 In view of the fact that the emission band originating from the 520 excimer triplet states of carbazole groups with a maximum at 521 530 nm corresponds to the band associated with the emission of 522 Ir(ppy) 3 molecules, it is difficult to clearly indicate which kind of [42] and PBD molecules (about 6 D) [43] we can suggest that 576 detrapping from traps formed on the matrix within the distance 577 of 2.3 nm, independently on the type of traps and recombination 578 centres may generate excitons on the iridium complex molecules.…”

Mediation of exciton concentration on magnetic field effects in NPB : Alq3-based heterojunction OLEDs

“…Since there are two spin directions of electrons and holes, there are also two types of polaron pairs, namely, singlet polaron pair (PP S ) and triplet polaron pair (PP T ). 10 Under the hyperne interaction (HFI), 24,25 PPs and PP T will undergo spin-mixing and transform into each other (PP S 4 PP T ), which is called inter-system crossing (ISC) induced by HFI [Fig. 4(a)].…”

“…8 This inhibition will reach saturation within a few mT. 24,28 The Coulomb interaction leads to the further conversion of PP S and PP T into singlet exciton (S 1,Alq3 ) and triplet exciton (T 1,Alq3 ). S 1,Alq3 is capable of directly radiating prompt uorescence (PF).…”

Abnormal magnetic field effects in doped organic light-emitting devices

“…发光增强 [1] , 表现为在外加较小磁场下快速增加的 MEL; 同时, 由于 1 PP较 3 PP的离子性更强, 1 PP还可以 解离为自由电子空穴, 从而使器件电流增加 [29] , 表 http://engine.scichina.com/doi/10.1360/N972018-00434 材 料 和 客 体 材 料 之 间 存 在 Förster和 Dexter能 量 转 移 [16] . 因此 [31,32] . 因此器件中TQA反应强度 [12] .…”