Photovoltaic technology converting solar energy into electricity is being recognized as an essential component of future renewable energy production. It is crucial to develop advanced materials and device architectures to further boost the performance of photovoltaic systems. Computer simulation plays an increasingly important role in the research and development of new materials and devices. We have developed several multiscale simulation tools to model the interaction between charge and electromagnetic field, and to investigate the energy conversion mechanism in novel photovoltaic materials, for instance, organic and nanostructured semiconductor solar cells.<br/>We employed the discrete dynamic Monte Carlo approach and the macroscopic continuum device model to quantitatively predict the optoelectronic properties of organic semiconductors. To quantize the structure-property relationships, we have developed a quantum mechanical method based on non-equilibrium Green’s function techniques to study the performance of nanowire-based photovoltaic devices. To enhance the light absorption, an effective method for achieving light confinement in the photoactive layer is the use of metallic nanostructures that support localized surface plasmon resonances. Plasmonic solar cells involve processes that couple light both with nanometallic structures and semiconducting photoactive layers. We applied a multiscale quantum mechanics/electromagnetics (QM/EM) method to model the current-voltage characteristics and optical properties of plasmonic nanowire solar cells. Classical electrodynamics of a metallic nanoparticle is directly coupled to quantum mechanical simulations of silicon nanowire solar cells. We found a dramatic enhancement in performance of nanowire solar cells due to the near-field effect of plasmonic structures, and particularly an increase of ~70% in internal quantum efficiency by coupling light into the n-doped part of the device as compared to the p-doped counterpart. We simulated the optical response of a tandem photovoltaic cell and demonstrated that multiple QM regions are coupled through the classical EM model.

Multiscale simulations of novel photovoltaic materials

251st National Meeting (2016)

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