Fundamentals, Advances, and Artifacts in Circularly Polarized Luminescence (CPL) Spectroscopy

Abstract

Objects are chiral when they cannot be superimposed with their mirror image. Materials can emit chiral light with an excess of right‐ or left‐handed circular polarization. This circularly polarized luminescence (CPL) is key to promising future applications, such as highly efficient displays, holography, sensing, enantiospecific discrimination, synthesis of drugs, quantum computing, and cryptography. Here, a practical guide to CPL spectroscopy is provided. First, the fundamentals of the technique are laid out and a detailed account of recent experimental advances to achieve highly sensitive and accurate measurements is given, including all corrections required to obtain reliable results. Then the most common artifacts and pitfalls are discussed, especially for the study of thin films, for example, based on molecules, polymers, or halide perovskites, as opposed to dilute solutions of emitters. To facilitate the adoption by others, custom operating software is made publicly available, equipping the reader with the tools needed for successful and accurate CPL determination.

Efficient Mechanochemical Conversion of Elemental Sulfur to Circularly Polarized Luminescent Sulfur Quantum Dots

“…The key objective of this study is to develop CPL-active Sdots and to explore the excited state chiral properties. CPL measurements were conducted following the considerations for accurate measurements, ensuring a reliable interpretation of the experimental data . Intriguingly, the l -Sdots displayed clear signs of CPL when excited at 365 nm (Figure ).…”

“…CPL measurements were conducted following the considerations for accurate measurements, ensuring a reliable interpretation of the experimental data. 42 Intriguingly, the L-Sdots displayed clear signs of CPL when excited at 365 nm (Figure 5). L-Sdots showed CPL bands centered at around 467 nm.…”

Ab initio investigations of circularly polarised luminescence in Samarium(iii)-based complexes

“…1 The first reported measurements can be attributed to Samoilov for a crystal of sodium uranyl acetate in 1948 2 and to Emeis and Oosterhoff for a bicyclic ketone in 1967. 3 Since, noteworthy improvements have been made in experimental measurements 4,5 and the research field on CPL has steadily progressed, bringing many applications in its wake. Among them, one can mention circularly polarised light-emitting diodes, 6 probes of chiral environments 7 and security inks.…”

Inverted and Amplified Circularly Polarized Luminescence Behavior Originated from Structure–Activity Regulation of Achiral Pyrene-Based Polymers in Chiral Coassemblies

“…Circularly polarized luminescence (CPL) materials have received significant attention in recent years due to their potential applications in optical devices and optical information encryption. − A critical parameter for evaluating the performance of CPL materials is the luminescence dissymmetry factor ( g lum ). − It is defined as g lum = 2 × ( I L – I R )/( I L + I R ) where I L and I R denote the intensities of left- and right-handed circularly polarized light, respectively . Theoretically, the g lum value ranges from −2 to +2 where −2 represents purely right-handed CPL and +2 represents purely left-handed CPL .…”