Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting Diodes
Key factors to control the efficiency in iridium doped red and green phosphorescent light emitting diodes (PhOLEDs) are discussed in this review: exciton confinement, charge trapping, dopant concentration and dopant molecular structure. They are not independent from each other but we attempt to pres...
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| Format: | Article |
| Language: | English |
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Wiley
2012-01-01
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| Series: | Advances in Materials Science and Engineering |
| Online Access: | http://dx.doi.org/10.1155/2012/794674 |
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| author | Boucar Diouf Woo Sik Jeon Ramchandra Pode Jang Hyuk Kwon |
| author_facet | Boucar Diouf Woo Sik Jeon Ramchandra Pode Jang Hyuk Kwon |
| author_sort | Boucar Diouf |
| collection | DOAJ |
| description | Key factors to control the efficiency in iridium doped red and green phosphorescent light emitting diodes (PhOLEDs) are discussed in this review: exciton confinement, charge trapping, dopant concentration and dopant molecular structure. They are not independent from each other but we attempt to present each of them in a situation where its specific effects are predominant. A good efficiency in PhOLEDs requires the triplet energy of host molecules to be sufficiently high to confine the triplet excitons within the emitting layer (EML). Furthermore, triplet excitons must be retained within the EML and should not drift into the nonradiative levels of the electron or hole transport layer (resp., ETL or HTL); this is achieved by carefully choosing the EML’s adjacent layers. We prove how reducing charge trapping results in higher efficiency in PhOLEDs. We show that there is an ideal concentration for a maximum efficiency of PhOLEDs. Finally, we present the effects of molecular structure on the efficiency of PhOLEDs using red iridium complex dopant with different modifications on the ligand to tune its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies. |
| format | Article |
| id | doaj-art-43d130e25d6e423ba077c32d6df931cc |
| institution | Kabale University |
| issn | 1687-8434 1687-8442 |
| language | English |
| publishDate | 2012-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Materials Science and Engineering |
| spelling | doaj-art-43d130e25d6e423ba077c32d6df931cc2025-02-03T01:23:41ZengWileyAdvances in Materials Science and Engineering1687-84341687-84422012-01-01201210.1155/2012/794674794674Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting DiodesBoucar Diouf0Woo Sik Jeon1Ramchandra Pode2Jang Hyuk Kwon3Department of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701, Republic of KoreaDepartment of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701, Republic of KoreaDepartment of Physics, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701, Republic of KoreaDepartment of Information Display, Kyung Hee University, Dongdaemoon-gu, Seoul 130-701, Republic of KoreaKey factors to control the efficiency in iridium doped red and green phosphorescent light emitting diodes (PhOLEDs) are discussed in this review: exciton confinement, charge trapping, dopant concentration and dopant molecular structure. They are not independent from each other but we attempt to present each of them in a situation where its specific effects are predominant. A good efficiency in PhOLEDs requires the triplet energy of host molecules to be sufficiently high to confine the triplet excitons within the emitting layer (EML). Furthermore, triplet excitons must be retained within the EML and should not drift into the nonradiative levels of the electron or hole transport layer (resp., ETL or HTL); this is achieved by carefully choosing the EML’s adjacent layers. We prove how reducing charge trapping results in higher efficiency in PhOLEDs. We show that there is an ideal concentration for a maximum efficiency of PhOLEDs. Finally, we present the effects of molecular structure on the efficiency of PhOLEDs using red iridium complex dopant with different modifications on the ligand to tune its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies.http://dx.doi.org/10.1155/2012/794674 |
| spellingShingle | Boucar Diouf Woo Sik Jeon Ramchandra Pode Jang Hyuk Kwon Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting Diodes Advances in Materials Science and Engineering |
| title | Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting Diodes |
| title_full | Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting Diodes |
| title_fullStr | Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting Diodes |
| title_full_unstemmed | Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting Diodes |
| title_short | Efficiency Control in Iridium Complex-Based Phosphorescent Light-Emitting Diodes |
| title_sort | efficiency control in iridium complex based phosphorescent light emitting diodes |
| url | http://dx.doi.org/10.1155/2012/794674 |
| work_keys_str_mv | AT boucardiouf efficiencycontroliniridiumcomplexbasedphosphorescentlightemittingdiodes AT woosikjeon efficiencycontroliniridiumcomplexbasedphosphorescentlightemittingdiodes AT ramchandrapode efficiencycontroliniridiumcomplexbasedphosphorescentlightemittingdiodes AT janghyukkwon efficiencycontroliniridiumcomplexbasedphosphorescentlightemittingdiodes |