Fremstilling af White Light-emitting elektrokemiske celler med Stable Emission fra Exciplexes
Summary
The authors present a method for fabricating stable white-light-emitting electrochemical cells utilizing emission from exciplexes formed between a blue-emitting fluorene polymer and aromatic amines.
Abstract
Forfatterne fremlægge en fremgangsmåde til fremstilling stabil hvid lysemission fra polymer lysemitterende elektrokemiske celler (PLECs) med et aktivt lag, som består af blå-fluorescerende poly (9,9-di-n-dodecylfluorenyl-2,7-diyl) ( PFD) og π-konjugerede triphenylamin molekyler. Denne hvide lys emission stammer fra exciplexes dannet mellem PFD og aminer i elektronisk exciterede tilstande. En indretning indeholdende PFD, 4,4 ', 4' '- tris [2-naphthyl (phenyl) amino] triphenylamin (2-TNATA), poly (ethylenoxid) og K 2 CF3 SO 3 viste hvidt lysemission med Commission Internationale de l'Éclairage (CIE) koordinater (0,33, 0,43) og et farvegengivelsesindeks (CRI) på Ra = 73 ved en påtrykt spænding på 3,5 V. konstant spænding målinger viste, at CIE koordinater (0,27, 0,37), Ra af 67, og farven emission observeret umiddelbart efter påføring af en spænding på 5 V var næsten uændret og stabil efter300 sek.
Introduction
Research and development of polymer light-emitting electrochemical cells (PLECs) have expanded in recent years.1-15 PLECs are similar to organic light-emitting diodes (OLEDs) in that both are surface emitting organic devices and are expected to find their way into future lighting applications. OLEDs are already on the market, but the cost is still high, one reason being that OLEDs need a complicated device structure with multiple layers. In contrast, PLECs have a very simple device structure which consists of a single active layer (emitting layer) between a pair of electrodes. This means that PLECs are suited to mass production processes such as roll-to-roll printing and coating.
A PLEC has an active layer consisting of a fluorescent π-conjugated polymer (FCP). The FCP can be electrochemically doped with a polymer electrolyte (a mixture of an ion conducting polymer and a salt). The FCP is p-doped on the anode side and n-doped on the cathode side during operation, and generates excitons which emit light between the p- and n-doped regions. Therefore, the emission color reflects the exciton emission (=fluorescence) wavelength of the FCP.
Stable white light emission is important for lighting applications, and color mixing techniques which employ two or more emitters have been widely used to achieve this.10-14 Recently, we presented a different approach for obtaining stable white light emission, using an active layer which contains blue-fluorescent poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) and π-conjugated aromatic amines15. This white light emission comes from exciplexes formed between PFD and amine molecules in excited states. Exciplex emission has a broader spectrum compared to the exciton emission from the PDF and/or amines, which gives it a color close to that of natural light. This translates to a higher color rendering index (CRI), which is preferable for lighting applications.
In this article, the authors describe the procedure used to fabricate the exciplex based LECs and show the stability of their white light emission.
Protocol
Representative Results
Discussion
LEC har et aktivt lag indeholdende hydrofob PFD og aromatiske aminer, og hydrofile polyethylenoxid og KCF 3 SO 3. Fordi disse materialer har meget forskellige opløseligheder, omhyggelig forberedelse af spin coatingopløsningen er kritisk for at undgå ufuldstændige solvatisering. Hver skal først opløst separat og fuldstændigt i opløsningsmidler med tilstrækkelig opløsende evne, så opløsningerne blandes sammen til dannelse af en ensartet blanding. Balancere exciton og exciplex emissioner e…
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
Dette arbejde blev delvist støttet af en Grant-in-Støtte til videnskabelig forskning (nr 24.225.003). Dette arbejde blev støttet økonomisk af JX Nippon Oil & Energy Corporation.
Materials
| Poly(9,9-di-n-dodecylfluorenyl-2,7-diyl) (PFD) | Aldrich | 571660 | |
| 4,4’,4’’-Tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA) | Aldrich | 768669 | |
| 9,9-Dimethyl-N,N’-di(1-naphthyl)-N,N’-diphenyl-9H-fluorene-2,7-diamine (DMFL-NPB) | Aldrich | ||
| Poly(ethylene oxide) (PEO) | Aldrich | 182028 | |
| Potassium tirifluoromethansulfonate (KCF3SO3) | Aldrich | 422843 | dried under vacuum at 200 °C for 2 hr prior to use |
| Chloroform | Kanto Chemical Co. | 08097-25 | dehydrated |
| Cyclohexanone | Kanto Chemical Co. | 07555-00 | |
| SCAT 20-X (detergent) | Daiichi Kogyo Seiyaku | diluted with water | |
| Acetone | Kanto Chemical Co. | 01866-25 | Electronic grage |
| 2-propanol | Kanto Chemical Co. | 32439-75 | Electronic grage |
| 13mm GD/X Disposable Filter Device PVDF Filter Media, Polypropylene Housing | Whatman | 6872-1304 | |
| UV/O3 Treating Unit | SEN Lights Co. | SSP16-110 | |
| Spectral Photo Detector | Otsuka Electronics | MCPD 9800 | |
| Voltage Current Source Monitor | ADCMT | 6241A | |
| Evaporation Mask | Tokyo Process Service Co., Ltd. | NA | The evaporation mask was wet-etched to create openings for patterned deposition of aluminum. The size of the mask is 100 mm x 100 mm x 0.2 mm-thick. |
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