Enhanced photoluminescence of corrugated Al₂O₃film assisted by colloidal CdSe quantum dots

Abstract

We present the enhanced photoluminescence (PL) of a corrugated AlO film enabled by colloidal CdSe quantum dots. The colloidal CdSe quantum dots are fabricated directly on a corrugated AlO substrate using an electrochemical deposition (ECD) method in a microfluidic system. The photoluminescence is excited by using a 150 nm diameter ultraviolet laser spot of a scanning near-field optical microscope. Owing to the electron transfer from the conduction band of the CdSe quantum dots to that of AlO, the enhanced photoluminescence effect is observed, which results from the increase in the recombination rate of electrons and holes on the AlO surface and the reduction in the fluorescence of the CdSe quantum dots. A periodically-fluctuating fluorescent spectrum was exhibited because of the periodical wire-like corrugated AlO surface serving as an optical grating. The spectral topographic map around the fluorescence peak from the AlO areas covered with CdSe quantum dots was unique and attributed to the uniform deposition of CdSe QDs on the corrugated AlO surface. We believe that the microfluidic ECD system and the surface enhanced fluorescence method described in this paper have potential applications in forming uniform optoelectronic films of colloidal quantum dots with controllable QD spacing and in boosting the fluorescent efficiency of weak PL devices.

InGaN blue resonant cavity micro-LED with RGY quantum dot layer for broad gamut, efficient displays

“…This improvement is crucial for the development of high-performance displays and optical devices. Commonly used nano-scattering particles include titanium dioxide (TiO 2 )[ 13 , 22 ], zirconium dioxide (ZrO 2 )[ 26 , 27 ], silica (SiO 2 )[ 23 ], and aluminum oxide (Al 2 O 3 )[ 28 ], among others. These particles are selected for their high refractive index, chemical stability, and favorable optical properties, which effectively scatter visible light and boost the luminous efficiency of QDs.…”

Regulating the Fluorescence Emission of CdSe Quantum Dots Based on the Surface Ligand Exchange with MAA

“…Such properties provide a new tunable metal‐oxide semiconductor (MOS) for alumina in nano‐heterojunction devices. The electron transfer of long‐chain OA ligands deposited on AAO substrate has been studied in the previous work 44 . In this paper, we used a 360 nm laser to induce near‐field fluorescence to further investigate the effect of the exchange of surface ligands.…”

Fluorescence spectra of colloidal self-assembled CdSe nano-wire on substrate of porous Al2O3/Au nanoparticles*

“…The colloidal CdSe quantum dots were prepared by our previous methods. [27,28] The size of single QD was about 3.5 nm, and its surface was packaged with the oleic acid molecules. The number density of gold NPs and CdSe QDs in raw solution were, respectively, about 2.0 × 10 17 ml −1 and 2.0 × 10 18 ml −1 .…”