Dynamics of Polarons in Guest-Host-System Polymer Light Emitting Devices

1997 ◽  
Vol 488 ◽  
Author(s):  
E.J.W. List ◽  
J. Partee ◽  
W. Graupner ◽  
J. Shinar ◽  
G. Leising
Keyword(s):  
Energy Transfer ◽  
Magnetic Resonance ◽  
Excitation Energy ◽  
Active Layer ◽  
Excitation Energy Transfer ◽  
Light Emitting ◽  
Host System ◽  
Light Emitting Devices ◽  
Polymer Light Emitting Devices

AbstractThe conjugated ladder-type poly(paraphenylene) is an attractive material for blue polymer light emitting devices (PLED). Blending the active layer with small amounts of a red emitting guest polymer, the emission shifts from blue to red with increasing guest concentration due to efficient excitation energy transfer. The results of photoluminescence detected magnetic resonance, electroluminescence detected magnetic resonance measurements and current detected magnetic resonance measurements on PLEDs based on 0.05w%/o - 2w%/o red emitting poly(perylene-co-diethynylbenzene) (PPDB) in the active layer of the PLED are presented and discussed.

Excitation energy transfer in segmented ladder-type poly (para-phenylene) blue light emitting diodes

1995 ◽  
Vol 96 (3) ◽  
pp. 167-170 ◽  
Author(s):  
C. Paar ◽  
J. Stampfl ◽  
S. Tasch ◽  
H. Kreimaier ◽  
G. Leising ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Blue Light ◽  
Light Emitting Diodes ◽  
Excitation Energy Transfer ◽  
Light Emitting

scholarly journals Investigation of Energy Transfer in Star-Shaped White Polymer Light-Emitting Devices via the Time-Resolved Photoluminescence

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1719 ◽  
Author(s):  
Hui He ◽  
Xiaoqing Liao ◽  
Jiang Cheng ◽  
Ying Li ◽  
Junsheng Yu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Current Efficiency ◽  
Intermolecular Interactions ◽  
Efficient Energy Transfer ◽  
Time Resolved ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Efficient Energy ◽  
Polymer Light Emitting Devices ◽  
Time Resolved Photoluminescence

A series of white polymer light-emitting devices (WPLEDs) were fabricated by utilizing star-shaped white-emission copolymers containing tri[1-phenylisoquinolinato-C2,N]iridium (Ir(piq)3), fluorenone (FO) and poly(9,9-dioctylfluorene) (PFO) as red-, green- and blue-emitting (RGB) components, respectively. In these WPLEDs, a maximum current efficiency of 6.4 cd·A−1 at 20 mA·cm−2 and Commission Internationale d’Eclairage (CIE) coordinates of (0.33, 0.32) were achieved, and the current efficiency was still kept to 4.2 cd·A−1 at the current density of 200 mA·cm−2. To investigate energy transfer processes among the three different chromophores of the star-shaped copolymers in these WPLEDs, the time-resolved photoluminescence (PL) spectra were recorded. By comparing the fluorescence decay lifetimes of PFO chromophores in the four star-like white-emitting copolymers, the efficient energy transfer from PFO units to Ir(piq)3 and FO chromophores was confirmed. From time-resolved PL and the analysis of energy transfer process, the results as follows were proved. Owing to the star-like molecular structure and steric hindrance effect, intermolecular interactions and concentrations quenching in the electroluminescence (EL) process could also be sufficiently suppressed. The efficient energy transfer also reduced intermolecular interactions’ contribution to the enhanced device performances compared to the linear single-polymer white-light systems. Moreover, saturated stable white emission results from the joint of energy transfer and trap-assisted recombination. This improved performance is expected to provide the star-like white-emitting copolymers with promising applications for WPLEDs.

Excitation energy transfer in guest host systems studied by magnetic resonance techniques

1999 ◽  
Vol 102 (1-3) ◽  
pp. 1077-1078 ◽  
Author(s):  
E.J.W. List ◽  
J. Partee ◽  
W. Graupner ◽  
J. Shinar ◽  
G. Leising
Keyword(s):  
Energy Transfer ◽  
Magnetic Resonance ◽  
Excitation Energy ◽  
Excitation Energy Transfer

Singlet and Triplet Energy Transfer in Phosphorescent Dye Doped Polymer Light Emitting Devices

2001 ◽  
Vol 708 ◽  
Author(s):  
Yong-Young Noh ◽  
Chang-Lyoul Lee ◽  
Hae Won Lee ◽  
Hyun-Nam Cho ◽  
Jang-Joo Kim
Keyword(s):  
Energy Transfer ◽  
Conjugated Polymer ◽  
Triplet Energy ◽  
Efficient Energy Transfer ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Host Materials ◽  
Triplet Energy Transfer ◽  
Polymer Light Emitting Devices ◽  
Doped Polymer

ABSTRACTEffect of host polymers on energy transfer in phosphorescent dye doped polymer light emitting devices has been investigated. Poly (N-vinylcarbazol) [PVK] and poly (9,9'-di-n-hexyl-2,7-fluorene-alt-1,4(2,5dinhexyloxy) phenylene) [PFHP] were examined as the host materials for the phosphorescent dyes fac tris(2-phenypyridine) irdium(III) [Ir(ppy)3] and 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) [PtOEP]. The host and guest materials have the large spectrum overlap between the emission of the hosts and absorption of the guests. When the guests were doped in PVK, the singlet-singlet and triplet-triplet energy transfer took place efficiently. On the contrary, the energy transfer did not take place from φ-conjugated polymer PFHP to the guests, even though common requirements for Förster and Dexter energy transfer were fulfilled. Host aggregation in PFHP based phosphorescent dye doped light emitting devices can play an undesired role obstructing efficient energy transfer.

The Application of Poly(Phenylene) Type Polymers and Oligomers in Electroluminescent Color Displays

1997 ◽  
Vol 471 ◽  
Author(s):  
S. Tasch ◽  
C. Brandstätter ◽  
W. Graupner ◽  
S. Hampel ◽  
C. Hochfilzer ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
White Light ◽  
Light Emission ◽  
Excitation Energy Transfer ◽  
Blue Emission ◽  
Environmental Stability ◽  
Large Area ◽  
Light Emitting ◽  
Color Conversion

ABSTRACTDue to their high photoluminescence efficiency (>30%), high environmental stability and the good charge transport properties the derivatives of poly(paraphenylene) (PPP), as the laddertype PPP (LPPP) and the oligomer hexaphenyl, are very suitable materials to realise efficient, stable, large area blue organic light-emitting diodes (OLEDs). The emission of blue OLEDs can be efficiently converted into all other emission colors either by an external color conversion technique (ECCT) or an internal color conversion technique (ICCT) and hence are very interesting for a number of display applications:Firstly, we demonstrate the realisation of efficient red-green-blue (RGB) emission colors (representing the RGB-pixels in a multicolor display) by an external CCT. In this case the blue EL device is covered with highly fluorescenct dye/matrix layers, which are excited by the blue emission and emit photoluminescence light in a lower energetic range.Secondly, a new method for producing efficient white light-emitting polymer diodes (which are interesting for e.g. backlight sources in liquid crystal displays) based on a blend of two polymers is presented: a blue light-emitting m-LPPP and a red-orange emitter poly(perylene-co-diethynylbenzene) (PPDB). The red-orange emission is created within the EL device (ICCT) by an excitation energy transfer from m-LPPP into the energetically lower lying states of PPDB. This internal excitation energy transfer is very efficient, so that only a concentration of 0.05 weight % PPDB in the polymer blend is required in order to obtain white light emission.

Excitation energy transfer and spatial exciton confinement in polyfluorene blends for application in light-emitting diodes

2002 ◽  
Vol 12 (12) ◽  
pp. 3523-3527 ◽  
Author(s):  
Ana Charas ◽  
Jorge Morgado ◽  
J. M. G. Martinho ◽  
A. Fedorov ◽  
Luis Alcácer ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Excitation Energy ◽  
Light Emitting Diodes ◽  
Excitation Energy Transfer ◽  
Light Emitting
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