Despite the growing popularity of cyclic voltammetry, many students do not receive formalized training in this technique as part of their coursework. Confronted with self-instruction, students can be left wondering where to start. Here, a short introduction to cyclic voltammetry is provided to help the reader with data acquisition and interpretation. Tips and common pitfalls are provided, and the reader is encouraged to apply what is learned in short, simple training modules provided in the Supporting Information. Armed with the basics, the motivated aspiring electrochemist will find existing resources more accessible and will progress much faster in the understanding of cyclic voltammetry.

Ligand exchange reactions are commonly used to alter the surface chemistry of metal chalcogenide quantum dots; however, a lack of quantifiable data for these processes limits the rational functionalization of nanomaterials. Here, we quantify the X-type ligand exchange reaction between carboxylate-terminated ligands on PbS quantum dots via1H NMR spectroscopy. Using spectroscopic handles of both the native and exchange ligand, bound and free forms of each have been quantified as a function of exchange ligand concentration. We find that the equilibrium constants for the reaction between oleate-capped PbS quantum dots and undec-10-enoic acid are 2.23 ± 0.50 and 2.14 ± 0.42 for sets of nanocrystals prepared by two different synthetic methods. X-ray photoelectron, absorbance, and emission spectroscopies indicate that the carboxylate exchange reaction does not alter the lead ion coverage of the nanocrystal surface. The quantitative equilibrium constant determined herein can be used to improve control over partial ligand exchange reactions on PbS nanocrystals.

Luminaires and other lighting devices using organic light-emitting diode (OLED) sources have many advantages over their competitors for indoor lighting, including thin form factors that produce highly diffuse, potentially low-glare, lighting with excellent color rendering properties. However, several significant issues with OLED products have limited their commercial acceptance to date, including source efficacy, source lifetime, driver performance, and initial costs. The U.S. Department of Energy (DOE) has released four reports on OLED technologies to provide the lighting industry with information on the state of the technology. These reports include the evaluation of two different field deployment sites, a market analysis, and an independent assessment of the performance of several commercially available OLED products. This report builds on previous DOE efforts with OLED technology by updating information on a previously benchmarked OLED product (the Chalina luminaire from Acuity Brands) and provides new benchmarks on the performance of Brite 2 and Brite Amber OLED panels from OLEDWorks. During the tests described here, samples of these devices were subjected to continuous operation in stress tests at elevated ambient temperature environments of 35°C or 45°C. In addition, samples were also operated continuously at room temperature in a room temperature operational life test (RTOL). One goal of this study was to investigate whether these test conditions can accelerate failure of OLED panels, either through panel shorting or an open circuit in the panel. These stress tests are shown to provide meaningful acceleration of OLED failure modes, and an acceleration factor of 2.6 was calculated at 45°C for some test conditions. In addition, changes in the photometric properties of the emitted light (e.g., luminous flux and chromaticity maintenance) was also evaluated for insights into the long-term stability of these products compared to earlier generations. Because OLEDs are a lighting system, electrical testing was also performed on the panel-driver pairs to provide insights into the impact of the driver on long-term panel performance. The Chalina luminaire from Acuity Brands uses OLED panels made by LG Display. These panels utilize a 3tandem stack structure with one layer containing a blue fluorescent emitter and two layers containing combined green and red phosphorescent emitters. In this study, three different generations (denoted as Gen 1, Gen 2, and Gen 3) of OLED panels were found to be used in the tested Chalina luminaires. Gen 2 and Gen 3 OLED panels are characterized by a copper foil adhered to the back of the panel, whereas Gen 1 OLED panels have a mirror-like finish on the back. Chalina luminaires with Gen 1 panels were previously discussed in CALiPER 24.