Aufsatz in einer Fachzeitschrift
Photo-induced degradation mechanisms in 4P-NPD thin films
Details zur Publikation
Autor(inn)en: | Cielecki, P.; Adam, J.; Leissner, T.; Patil, B.; Madsen, M.; Rubahn, H.; Kjelstrup-Hansen, J.; Fiutowski, J. |
Verlag: | ELSEVIER |
Publikationsjahr: | 2018 |
Zeitschrift: | Organic Electronics |
Seitenbereich: | 114-119 |
Jahrgang/Band : | 63 |
Erste Seite: | 114 |
Letzte Seite: | 119 |
Seitenumfang: | 6 |
ISSN: | 1566-1199 |
eISSN: | 1878-5530 |
DOI-Link der Erstveröffentlichung: |
Zusammenfassung, Abstract
Efficiency-limiting degradation of organic compounds is one of the main bottlenecks suppressing rapid commercialization of organic optoelectronic devices. Herein, degradation mechanisms of N, N'-di-l-naphthalenyl [N, N'-diphenyl [1,1': 4', 1 '': 4 '', 1 '''-quaterphenyl]-4,4 '''-diamine (4P-NPD) - a blue emitter, host for triplet harvesting and hole transport material commonly used in a variety of organic devices, are investigated. Controlled degradation tests reveal the material stability under individual influence of air or light exposure; however, rapid and irreversible degradation when simultaneously exposed to both factors. Degradation originating from photoinduced oxidation of 4P-NPD is characterized via fluorescence lifetime measurements. At a longer degradation time of similar to 60 min, the fluorescence lifetime is found to stabilize. Exciton diffusion-based Monte Carlo simulations show that this fluorescence lifetime stabilization does not indicate the end of the degradation process. Defect concentration simulations, based on time-resolved measurements, show that the defect formation rate decreases as the degradation progresses. This self-inhibiting behavior indicates that the photo-induced oxidation proceeds through the excited state of 4P-NPD. The results provide insight into the degradation process of 4P-NPD, highly relevant for increasing the stability of 4P-NPD-based devices.
Efficiency-limiting degradation of organic compounds is one of the main bottlenecks suppressing rapid commercialization of organic optoelectronic devices. Herein, degradation mechanisms of N, N'-di-l-naphthalenyl [N, N'-diphenyl [1,1': 4', 1 '': 4 '', 1 '''-quaterphenyl]-4,4 '''-diamine (4P-NPD) - a blue emitter, host for triplet harvesting and hole transport material commonly used in a variety of organic devices, are investigated. Controlled degradation tests reveal the material stability under individual influence of air or light exposure; however, rapid and irreversible degradation when simultaneously exposed to both factors. Degradation originating from photoinduced oxidation of 4P-NPD is characterized via fluorescence lifetime measurements. At a longer degradation time of similar to 60 min, the fluorescence lifetime is found to stabilize. Exciton diffusion-based Monte Carlo simulations show that this fluorescence lifetime stabilization does not indicate the end of the degradation process. Defect concentration simulations, based on time-resolved measurements, show that the defect formation rate decreases as the degradation progresses. This self-inhibiting behavior indicates that the photo-induced oxidation proceeds through the excited state of 4P-NPD. The results provide insight into the degradation process of 4P-NPD, highly relevant for increasing the stability of 4P-NPD-based devices.
Schlagwörter
4P-NPD thin films, Degradation mechanisms, Exciton diffusion Monte Carlo simulations, Photo-oxidation, Time-resolved fluorescence spectroscopy
