Langmuir–Schaeffer Monolayers of Colloidal Nanocrystals for Cost‐Efficient Quantum Dot Light‐Emitting Diodes

Abstract

Quantum dot (QD) LEDs of high color purity, and low turn-on voltage and leakage current are prepared using a solvent free method. First, a monolayer of QDs is formed at the air/water interface, which is then transferred with a PDMS stamp onto the device. The method is applicable to large substrates and reduces materials consumption as compared to other deposition techniques.

Size-Dependent Oxidation of Monodisperse Silicon Nanocrystals with Allylphenylsulfide Surfaces

“…Luminescent, colloidally stable silicon nanocrystals are a new class of materials with a wide range of applications from medical imaging to optoelectronics such as light emitting diodes (LEDs) and solar cells . In contrast to II–VI and III–V semiconductor nanocrystals, the advantage of silicon, the element that dominates the microelectronics and photovoltaic industry, is its nontoxicity, earth abundance and low cost.…”

CdSe/ZnS Quantum Dot Thin Film Formation by an Electrospray Deposition Process for Light‐Emitting Devices

“…Therefore, material loss can be signifi cantly reduced by using the ESD process compared to the popular spin-coating process. [ 13,14 ] Direct and dry micro-patterning using the ESD process has also been demonstrated with masks. [ 15 ] The deposition of various organic and inorganic thin fi lms by the ESD technique has been reported previously for OLEDs, polymer light-emitting diodes, and solar cell applications.…”

“…The small red-shift of approximately 9 nm and broadening EL spectrum of the QD-LED are attributed to energy and charge transfer in denser QD density fi lms than those obtained in hexane solutions. [ 11,14 ] small 2014, 10, No. 20, 4142-4146 It is interesting to note that aromatic solvents, such as CB and DCB, can be adopted for QD-LED fabrication, and a brightness of 15 000 cd m -2 and a current effi ciency of over 4.0 cd A -1 (CB:DCB ≈7:3) were achieved by the ESD process, as shown in Figure 4 .…”

“…Figure c shows the photoluminescence (PL) of the QD solution and electroluminescence (EL) of the QD‐LED device with a narrow full‐width at half‐maximum (FWHM) of approximately 35 nm. The small red‐shift of approximately 9 nm and broadening EL spectrum of the QD‐LED are attributed to energy and charge transfer in denser QD density films than those obtained in hexane solutions …”

“…In addition, a small amount of a few tens of microliters of a QD solution is required in the ESD process while milliliters are required in the spin‐coating process for thin film formation. Therefore, material loss can be significantly reduced by using the ESD process compared to the popular spin‐coating process . Direct and dry micro‐patterning using the ESD process has also been demonstrated with masks .…”