Enhancement of the internal quantum efficiency in strongly coupled P3HT-C₆₀ organic photovoltaic cells using Fabry-Perot cavities with varied cavity confinement

The short exciton diffusion length in organic semiconductors results in a strong dependence of the conversion efficiency of organic photovoltaic (OPV) cells on the morphology of the donor-acceptor bulk-heterojunction blend. Strong light-matter coupling provides a way to circumvent this dependence by combining the favorable properties of light and matter via the formation of hybrid exciton-polaritons. By strongly coupling excitons in P3HT-C60 OPV cells to Fabry-Perot optical cavity modes, exciton-polaritons are formed with increased propagation lengths. We exploit these exciton-polaritons to enhance the internal quantum efficiency of the cells, determined from the external quantum efficiency and the absorptance. Additionally, we find a consistent decrease in the Urbach energy for the strongly coupled cells, which indicates the reduction of energetic disorder due to the delocalization of exciton-polaritons in the optical cavity.</p

Device Performance of Emerging Photovoltaic Materials (Version 3)

Following the 2nd release of the “Emerging PV reports,” the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2021. Updated graphs, tables, and analyses are provided with several performance parameters, e.g., power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application, and are put into perspective using, e.g., the detailed balance efficiency limit. The 3rd installment of the “Emerging PV reports” extends the scope toward triple junction solar cells

Device Performance of Emerging Photovoltaic Materials (Version 2)

Following the 1st release of the “Emerging photovoltaic (PV) reports”, the best achievements in the performance of emerging photovoltaic devices in diverse emerging photovoltaic research subjects are summarized, as reported in peer-reviewed articles in academic journals since August 2020. Updated graphs, tables, and analyses are provided with several performance parameters, e.g., power conversion efficiency, open-circuit voltage, short-circuit current density, fill factor, light utilization efficiency, and stability test energy yield. These parameters are presented as a function of the photovoltaic bandgap energy and the average visible transmittance for each technology and application and are put into perspective using, e.g., the detailed balance efficiency limit. The 2nd instalment of the “Emerging PV reports” extends the scope toward tandem solar cells and presents the current state-of-the-art in tandem solar cell performance for various material combinations.</p

NOX2, p22phox and p47phox are targeted to the nuclear pore complex in ischemic cardiomyocytes colocalizing with local reactive oxygen species.

BACKGROUND: NADPH oxidases play an essential role in reactive oxygen species (ROS)-based signaling in the heart. Previously, we have demonstrated that (peri)nuclear expression of the catalytic NADPH oxidase subunit NOX2 in stressed cardiomyocytes, e.g. under ischemia or high concentrations of homocysteine, is an important step in the induction of apoptosis in these cells. Here this ischemia-induced nuclear targeting and activation of NOX2 was specified in cardiomyocytes. METHODS: The effect of ischemia, mimicked by metabolic inhibition, on nuclear localization of NOX2 and the NADPH oxidase subunits p22(phox) and p47(phox), was analyzed in rat neonatal cardiomyoblasts (H9c2 cells) using Western blot, immuno-electron microscopy and digital-imaging microscopy. RESULTS: NOX2 expression significantly increased in nuclear fractions of ischemic H9c2 cells. In addition, in these cells NOX2 was found to colocalize in the nuclear envelope with nuclear pore complexes, p22(phox), p47(phox) and nitrotyrosine residues, a marker for the generation of ROS. Inhibition of NADPH oxidase activity, with apocynin and DPI, significantly reduced (peri)nuclear expression of nitrotyrosine. CONCLUSION: We for the first time show that NOX2, p22(phox) and p47(phox) are targeted to and produce ROS at the nuclear pore complex in ischemic cardiomyocytes

Advances in solution-processed multijunction organic solar cells

The efficiency of organic solar cells can benefit from multi-junction device architectures in which energy losses are substantially reduced. This review describes recent (2015 to mid-2018) developments in the field of solution-processed multi-junction organic solar cells. In this time lapse various strategies have been investigated and implemented to improve the performance of these devices. Next to developing new materials and processing methods for the photoactive and interconnecting layers, specific layers or stacks have been designed to increase light absorption and improve the photocurrent by utilizing optical interference effects. These activities have resulted in power conversion efficiencies that approach those of modern thin film photovoltaic technologies. Multi-junction cells require more elaborate and intricate characterization procedures to establish their efficiency correctly and a critical view on the results and new insights in this matter are discussed. Application of multi-junction cells in photoelectrochemical water splitting and upscaling towards a commercial technology are briefly addressed

Synthesis and characterization of new poly(thienylenevinylene)s with thioether side chains

The first poly(thienylene vinylene)s with alkylthio side chains are synthesized by the McMurry reductive polymerisation of the corresponding 2,5-dialdehydes. The polymers PTVa and b show good solubility and comparable optical properties, with the exception of the CD effect, present in PTVb due to its chiral side chains. Furthermore the polymers have optical properties that change upon modification of different parameters, such as the solvent and the temperature.</p

Synthesis and characterization of new poly(thienylenevinylene)s with thioether side chains

The first poly(thienylene vinylene)s with alkylthio side chains are synthesized by the McMurry reductive polymerisation of the corresponding 2,5-dialdehydes. The polymers PTVa and b show good solubility and comparable optical properties, with the exception of the CD effect, present in PTVb due to its chiral side chains. Furthermore the polymers have optical properties that change upon modification of different parameters, such as the solvent and the temperature

Substituted 2,1,3-Benzothiadiazole- And Thiophene-Based Polymers for Solar Cells - Introducing a New Thermocleavable Precursor

Alkoxysubstituted and unsubstituted 2,1,3-benzothiadiazoles were prepared and copolymerized with substituted and unsubstituted thiophenes using both Stille and Yamamoto cross-coupling reactions. One class of the materials bore thermally labile ester groups. The materials were all found to have a reduced band gap in the range of 1.69-1.75 eV and were explored in polymer photovoltaic devices as mixtures with the soluble fullerene PCBM. High open circuit voltages of up to 0.93 V and power conversion efficiencies (PCE) of up to 2.22% was observed for materials without the thermally labile groups. The thermocleavable materials have the advantage that they are insoluble after a thermal treatment, enabling a larger degree of processing freedom when preparing multilayer devices and they provide a better operational stability for the devices. So far the process of thermocleavage has led to poorer device performance than for the soluble precursor polymers; however, we found processing conditions that lead to a higher performance for the thermocleaved product, where open circuit voltages of up to 0.9 V could be obtained with power conversion efficiencies of up to 0.42%, representing a doubling as compared to the soluble precursor polymer