Research On Electronic Material Of Quantum Dots Light Emitting Diode Device

Quantum dot, a zero dimensional material, draw lots of attentions from all over the world due to its special features. Compared to the traditional light emitting diode(LED), LED based on quantum dots(QD-LED) has a variety of excellent advantages, including wide optical spectrum, tunable option and low power dissipation, which could be a next-generation lighting device. Currently, researches on QD-LED mainly focus on improving the luminescent efficiency, the stability of QD-LED, and non-radiative combination. Considering the above issues, in this thesis, we specifically studied the fabrication of QD-LED, the device efficiency influenced by hole transport layers and modification of QDs.Firstly, we discussed the fabrication process and the related factors of QD-LED devices in detail. Spin-coating method was adopted to deposit carrier transport layers and improvement of the quality of films was systematically investigated. Meanwhile, main reasons of failure of device were analyzed.Secondly, the performance of QD-LED influenced by hole transport layers was investigated. It was found that the thickness of PVK(HTL) is inversely proportional to maximal brightness, while it has the same proportional to the turn-on voltage and voltage at its maximal brightness. The device got a best maximal brightness(98.2 cd/m2) in all kind of device which the thickness of PVK was 35 nm.Additionally, New HTL material, i.e., TPD(N,N’-diphenyl-N,N’-bis(3-methylpheny))was investigated and results indicate that its 30 wt% doping were attempted to degrade the turn-on voltage(3.8 V) and improve the maximal current density(0.05 A/m2).Attempt of using Ga N material to modify QDs was adopted to reduce non-radiation recombination. The modification of QDs through encapsulated by Ga N film was proposed. Ga N film was successfully synthesized by MOD method under low annealing temperature(300℃)with a wide optical gap(3.45 e V). After proving that Ga N does not induce QD’s quenching, we use QDs encapsulated by Ga N to fabricate the QD-LED. QD-LED device has failed in emission and the failure of the device is investigated through the relevant measurements.