|
1
|
Tselekidou D, Papadopoulos K, Foris V, Kyriazopoulos V, Andrikopoulos KC, Andreopoulou AK, Kallitsis JK, Laskarakis A, Logothetidis S, Gioti M. A Comparative Study between Blended Polymers and Copolymers as Emitting Layers for Single-Layer White Organic Light-Emitting Diodes. MATERIALS (BASEL, SWITZERLAND) 2023; 17:76. [PMID: 38203932 PMCID: PMC10780062 DOI: 10.3390/ma17010076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 12/18/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024]
Abstract
Extensive research has been dedicated to the solution-processable white organic light-emitting diodes (WOLEDs), which can potentially influence future solid-state lighting and full-color flat-panel displays. The proposed strategy based on WOLEDs involves blending two or more emitting polymers or copolymerizing two or more emitting chromophores with different doping concentrations to produce white light emission from a single layer. Toward this direction, the development of blends was conducted using commercial blue poly(9,9-di-n-octylfluorenyl2,7-diyl) (PFO), green poly(9,9-dioctylfluorenealt-benzothiadiazole) (F8BT), and red spiro-copolymer (SPR) light-emitting materials, whereas the synthesized copolymers were based on different chromophores, namely distyryllanthracene, distyrylcarbazole, and distyrylbenzothiadiazole, as yellow, blue, and orange-red emitters, respectively. A comparative study between the two approaches was carried out to examine the main challenge for these doping systems, which is ensuring the proper balance of emissions from all the units to span the entire visible range. The emission characteristics of fabricated WOLEDs will be explored in terms of controlling the emission from each emitter, which depends on two possible mechanisms: energy transfer and carrier trapping. The aim of this work is to achieve pure white emission through the color mixing from different emitters based on different doping concentrations, as well as color stability during the device operation. According to these aspects, the WOLED devices based on the copolymers of two chromophores exhibit the most encouraging results regarding white color emission coordinates (0.28, 0.31) with a CRI value of 82.
Collapse
Affiliation(s)
- Despoina Tselekidou
- Nanotechnology Lab LTFN, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (K.P.); (A.L.); (S.L.)
| | - Kyparisis Papadopoulos
- Nanotechnology Lab LTFN, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (K.P.); (A.L.); (S.L.)
| | - Vasileios Foris
- Nanotechnology Lab LTFN, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (K.P.); (A.L.); (S.L.)
| | - Vasileios Kyriazopoulos
- Organic Electronic Technologies P.C. (OET), 20th KM Thessaloniki—Tagarades, GR-57001 Thermi, Greece;
| | - Konstantinos C. Andrikopoulos
- Department of Chemistry, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece; (K.C.A.); (A.K.A.); (J.K.K.)
| | - Aikaterini K. Andreopoulou
- Department of Chemistry, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece; (K.C.A.); (A.K.A.); (J.K.K.)
| | - Joannis K. Kallitsis
- Department of Chemistry, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece; (K.C.A.); (A.K.A.); (J.K.K.)
| | - Argiris Laskarakis
- Nanotechnology Lab LTFN, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (K.P.); (A.L.); (S.L.)
| | - Stergios Logothetidis
- Nanotechnology Lab LTFN, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (K.P.); (A.L.); (S.L.)
- Organic Electronic Technologies P.C. (OET), 20th KM Thessaloniki—Tagarades, GR-57001 Thermi, Greece;
| | - Maria Gioti
- Nanotechnology Lab LTFN, Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece; (K.P.); (A.L.); (S.L.)
| |
Collapse
|