Near infrared electroluminescence from Nd(TTA) 3 phen in solution-processed small molecule organic light-emitting diodes

Abstract

International audienceWe report on the near infrared electroluminescence properties of a Nd3+ complex with thenoyltrifluoroacetone and 1,10-phenantroline ligands in solution-processed organic light-emitting diodes. Spin-coated blends containing a 1,3-bis(9-carbazolyl)benzene host doped with the Nd3+ complex were found to exhibit a photoluminescence quantum yield of about 0.5%, regardless of the doping concentration level. Electroluminescent devices based on these small molecule blends showed the characteristic emission of Nd3+ at 890, 1060 and 1330 nm with an external quantum efficiency as high as 0.022%. These improved performances were mainly attributed to direct charge trapping and exciton formation on the near infrared emitter. Importantly, the efficiency roll-off at high current densities due to triplet-triplet exciton annihilation in the device containing 20 wt% of the complex was lower than what is typically observed in lanthanide complex-based electroluminescent devices. This is presumably due to the high triplet energy of the host material, which prevents guest-to-host energy-back transfer and thus host-guest triplet-triplet exciton annihilation

Review on the Electroluminescence Study of Lanthanide Complexes

“…In 2017, Shahalizad and co‐workers employed Nd‐6 (Scheme ) to fabricate OLEDs by the solution‐processing method. A small molecule mCP with high triplet energy level of 2.9 eV was used as the host to ensure efficient energy transfer.…”

Infrared Organic Light‐Emitting Diodes with Carbon Nanotube Emitters

“…However, very few organic materials emit in this spectral range and the ones that do typically suffer from poor emission efficiency. [5] Previous work focused on either small molecules, [6][7][8][9] polymers, [10] polymer nanocrystals [11] or solution processed quantum dots [12] . While these approaches certainly hold promise, important challenges remain.…”

Bright neodymium complexes for efficient near infra-red organic light emitting diodes

“…The electrical performance shown by device 3 is comparable with that of other efficient Nd-complex based devices. [24][25][26][27][28][29]31 Moreover, the irradiance shown by device 3 was observed at a lower voltage as compared to the reported ones, [24][25][26][27][28][29]31 which indicates that device 3 is ] (3). The single crystal X-ray analysis showed that complex 1 is nona-coordinated while complexes 2 and are octacoordinated, and they possess distorted square antiprismatic (D 4d ) and monocapped square antiprism (C 4v ) geometries, respectively.…”

“…28 In 2019, a Nd complex, [Nd(tta) 3 (phen)], based device was reported with an EQE of 0.034% (tta = thenoyl trifluoroacetone and phen = 1,10-phenanthroline). 29 Considering the performances of the above mentioned devices, more efficient devices are still needed to be designed and fabricated to meet the requirements of practical applications.…”