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The operating temperature of PV modules affects the rate of degradation. We show the extent to which module operating temperature can be reduced by increasing the efficiency of the PV module via a tandem architecture or singlet Fission, the latter being of interest as a potentially endothermic process. PV modules that employ tetracene as a singlet fission material are found to be resilient against degradation since the degradation product is transparent to solar radiation.

Carbon-based materials have an intrinsically weak spin-orbit coupling which imposes spin selection rules on many electronic transitions. The spin degree of freedom of electrons and nuclei can therefore play a crucial role in the electronic and optical properties of these materials. Spin-selection rules can be studied via magnetic resonance techniques such as electron-spin resonance and optically detected magnetic resonance as well as electrically detected magnetic resonance (EDMR). The latter has progressed in recent years to a degree where the observation of coherent spin motion via current detection has become possible, providing experimental access to many new insights into the role that paramagnetic centers play for conductivity and photoconductivity. While mostly applied to inorganic semiconductor materials such as silicon, this new, often called pulsed-(p) EDMR spectroscopy, has much potential for organic (carbon-based) semiconductors. In this study, progress on the development of pEDMR spectroscopy on carbon-based materials is reviewed. Insights into materials properties that can be gained from pEDMR experiments are explained and limitations are discussed. Experimental data on radiative polaron-pair recombination in poly[2-methoxy-5-(20-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) organic light emitting diodes (OLEDs) are shown, revealing that under operating conditions the driving current of the device can be modulated by spin-Rabi nutation of the polaron spin within the charge carrier pairs. From this experimental data it becomes clear that for polaron pairs, the precursor states during exciton formation, exchange interaction is not the predominant influence on the observed pEDMR spectra.

Electrically detected magnetic resonance is a sensitive technique for studying electron spins bound to phosphorus atoms in silicon. Using a high magnetic field of 8.6 T increases this sensitivity by accessing a mechanism for spin-to-charge conversion which is different to that in the more commonly used magnetic field of ∼0.33 T. The higher-field regime benefits from a long spin coherence time of over 100 µs because the phosphorus spins that are detected are not coupled to dangling-bonds. Additionally, the high field permits the spin qubits to reach an equilibrium polarization of over 95% at a temperature of 2.8 K. We demonstrate electrically detected Rabi oscillations of these electron spins in the high-field regime. The Rabi frequency is proportional to the square root of the excitation power as expected.