1.3 μm to 1.55 μm Tunable Electroluminescence from PbSe Quantum Dots Embedded within an Organic Device

Abstract

the precursors flowed into the heated section, where they quickly reacted to form NCs. The NC solution was then collected for absorption and photoluminescence measurements.Optical absorption spectra were acquired using a Hewlett-Packard 8453 diode array spectrometer. Photoluminescence spectra were acquired using a SPEX Fluorolog 1680 spectrometer, using right-angle collection. Samples were prepared by diluting the raw NC solutions in hexane. Quantum yields were determined by comparing the integrated emission of a given NC sample solution with that of an appropriate reference dye [18].

Electromagnetic Modeling of Outcoupling Efficiency and Light Emission in Near-Infrared Quantum Dot Light Emitting Devices

“…In addition, the optical mode overlap with the emissive QD layer is poor for the long wavelength (1.55 µm). We further note that the choice of ITO as the anode in this devices is not ideal, since the transparency of 150 nm ITO thickness for the IR electromagnetic wave is only about 70% at λ = 1.5 µm [3].…”

“…0.001% 1.3-1.55 µm PbSe nanocrystals in a monolayer [3] 0.0086% 1-1.6 µm core only PbS blended with a polymer [5] 0.27% ∼ 1.15 µm MEH-PPV-PbS and MEH-PPV-InAs [1] 0.5% 1-1.3 µm core-shell InAs/ZnSe and MEH-PPV polymer blend [4] 1.15% 1.3-1.5 µm PbS nanocrystals and a layer of pentacene [16] The electroluminescence EQE (η EL ) of QD-LEDs is expressed as the ratio of photons extracted into the viewing direction to electrons injected and can be written in simplified form as [17],…”

“…ϕ PL is the luminescence efficiency of NCs: Photons generated per exciton captured [1]. The reported luminescence efficiency ϕ PL of IR-NCs in solution reaches more than 80% [19], while that in solid films drops to 1% range due to aggregated quenching [3,19,20]. The usual term representing the singlet/triplet capture ratio in OLEDs does not appear in this equation due to the large spin-orbit coupling in QDs [21].…”

“…A basic configuration of bottom-emitting IR QD-LED is selected [3]. The elementary device depicted in Figure 2 corresponds …”

“…Other applications for which infrared (IR) active NCs have been proposed to date include: IR luminescence LEDs [3][4][5], IR detectors [6][7][8][9], modulators in the extended telecommunications-wavelength band (1200-1700 nm) [10], photovoltaic [11], IR laser technologies [12,13], thermoelectrics devices [14], and long-wavelength labeling [15].…”