Circularly Polarized Absorption and Luminescence of Semiconductor Eu‐OCN Nanocrystals in the Blue Region of the Electromagnetic Spectrum

Abstract

Semiconductor nanomaterials with efficient polarized‐light control in the blue region of the visible spectrum are promising candidates for modern and future photo‐information technology, display devices, and optical sensing applications. New‐type semiconductor Eu(OCN)2 nanocrystals with circularly polarized absorption (CD: circular dichroism) and emission (CPL: circularly polarized luminescence) under an applied magnetic field are demonstrated here for the first time. The effective CD signal at 1.6 T was observed at approximately 440 nm. The dissymmetry factor of CPL under 100 K, gM‐CPL, was estimated to be 0.01. These characteristic circularly polarized absorption and emission phenomena of Eu(OCN)2 nanocrystals should be caused by combination between the “Faraday A and C terms” of the magnetic moment in the excited state. Polarized‐light control using Eu(OCN)2 nanocrystals in the blue‐light region of the electromagnetic spectrum is a large first step into a new world of photo‐functional semiconductor nanomaterials.

Full-color and white circularly polarized luminescence from CdSe/ZnS quantum dots by chiral templates of cellulose nanocrystals

“…3d, which are significantly enhanced compared to those reported from fluorescent semiconductor nanocrystals based on other methods. [32][33][34][35][36][37][38][39][40] Therefore, full-color CPL from CdSe/ZnS QDs with a high dissymmetry factor has been achieved by a CNC template via EISA, which is schematically illustrated in Schemes 1a and b.…”

“…Herein, full-color CPL of CdSe/ZnS QDs is demonstrated based on helical pitch adjustment of CNC chiral templates, where extraordinary g lum values of À0.66, À0.76 and À0.84 are realized for the blue, green and red-emitting QDs (denoted by B-QDs, G-QDs and R-QDs), respectively, superior compared to the previous reports for fluorescent semiconductor nanocrystals. [32][33][34][35][36][37][38][39][40] On the other hand, white CPL has attracted much attention recently. [41][42][43] However, most white CPLs achieved by chiral luminophores had very low |g lum |, on the order of 10 À4 -10 À3 .…”

“…[28][29][30][31] Non-trivial circular dichroism (CD) and a School of Physical Science and Technology, Ningbo University, CPL of fluorescent semiconductor nanocrystals have drawn particular attention. [32][33][34][35][36][37][38] Although semiconductor quantum dots (QDs) and quantum rods have been introduced into the CNC chiral template recently, 39,40 full-color CPL from semiconductor nanocrystals with high |g lum | is still desirable. Herein, full-color CPL of CdSe/ZnS QDs is demonstrated based on helical pitch adjustment of CNC chiral templates, where extraordinary g lum values of À0.66, À0.76 and À0.84 are realized for the blue, green and red-emitting QDs (denoted by B-QDs, G-QDs and R-QDs), respectively, superior compared to the previous reports for fluorescent semiconductor nanocrystals.…”

“…[44][45][46] CPLs based on the CNC chiral templates, however, were limited to narrowband so far. [32][33][34][35][36][37][38][39][40] The research on broadband circular polarizing films is still in its infancy. 47,48 To the best of our knowledge, white CPL based on CNCs has not been reported yet.…”

Remarkable Effects of External Magnetic Field on Circularly Polarized Luminescence of EuIII(hfa)3 with Phosphine Chirality

“…Organic and organometallic luminophores are crucial for realizing high‐performance photoluminescence (PL), electroluminescence, optoelectronic, and sensing devices. Recently, optically active substances emitting circularly polarized luminescence (CPL) have been shown to exhibit high tunability of the CPL wavelength, thus making the rational design of organometallic complexes with high Kuhn's dissymmetry ratios ( g CPL ) a challenging task [1–14] . Among the organometallic complexes, optically active lanthanides coordinated with chiral organic ligands exhibit very narrow full‐width at half‐maximum (FWHM) CPL bands for the 4f–4f transitions in the visible and near‐infrared regions [15–24] …”