Tillverkning av White Light-emitting elektrokemiska celler med stabil Emission från 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
Presenterar författarna en metod för tillverkning av en stabil vit ljusemission från polymer Ijusemitterande elektrokemiska celler (PLECs) som har ett aktivt skikt, som består av blå-fluorescerande poly (9,9-di-n-dodecylfluorenyl-2,7-diyl) ( PFD) och π-konjugerade trifenylamin molekyler. Denna ljusemission vit härstammar från exciplexes bildas mellan PFD och aminer i elektroniskt exciterade tillstånd. En anordning som innehåller PFD, 4,4 ', 4' '- tris [2-naftyl (fenyl) amino] trifenylamin (2-TNATA), Poly (etylenoxid) och K 2 CF 3 SO 3 visade vitt ljusemission med Commission Inter de l'éclairage (CIE) koordinaterna för (0,33, 0,43) och ett färgåtergivningsindex (CRI) Ra = 73 vid en pålagd spänning på 3,5 V. mätningar konstant spänning visade att CIE koordinaterna av (0,27, 0,37), Ra 67 och emissions färg observeras omedelbart efter applicering av en spänning på 5 V var nästan oförändrad och 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 ett aktivt skikt innehållande hydrofob PFD och aromatiska aminer, och hydrofil polyetylenoxid och KCF 3 SO 3. Eftersom dessa material har mycket olika löslighet, är noggranna förberedelser av spinnbeläggningslösningen avgörande för att undvika ofullständig solvatisering. Varje måste först lösas separat och fullständigt i lösningsmedel med tillräcklig solvatiserande förmåga, då de lösningarna blandas samman för att bilda en enhetlig blandning. Balansera exciton och excipl…
Disclosures
The authors have nothing to disclose.
Acknowledgements
Detta arbete har delvis stöd av en Grant-i-Stöd för vetenskaplig forskning (nr 24.225.003). Detta arbete stöddes ekonomiskt av 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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