Solar energy is a vast and inexhaustible resource. Capturing and utilizing this resource is a primary focus of numerous commercial and federal agencies. This focus is further prioritized by rising fossil fuel costs, the depletion of fossil fuel reserves and stimulus initiatives for alternate energy sources. The creation of a highly efficient solar energy semiconductor device will provide a renewable energy transition platform taking full advantage of this natural resource.
Several technological challenges exist in order realize higher efficiency solar capture devices, such as semiconductor-based solar cells. For example, these solar cells must expand their operating band gap energy range. This generally refers to the energy difference (measured in electron volts (eV)) between the top of the Valence Band (which is the highest range of electron energies where electrons are normally present) and the bottom of the Conduction Band (the electron energy range that is sufficient to free an electron from binding with its individual atom). Combined with band gap energy, efficient solar device designs may take into account the varying speeds of photons. By choosing the optimal semiconductor material, the solar energy device can focus on the widest possible band gap range, thereby collecting the largest range of photonic energy. Further, improved grain boundary properties may be required for increased strength. As solar energy devices typically experience thermal stresses, understanding a solar material grain boundary is vital to prevent material distortion. Acting as the interface between two grains in a polycrystalline material, the grain boundary can disrupt the motion of impurities/dislocations caused by energy transfer so as to reduce/optimize crystallite size improving material strength. Finally, the ability of a solar device to collect photons (without significant energy reflection) correlates device efficiency with energy absorption rates to maximize the number of “donor”/“acceptor” exchanges that take place to generate electrical energy.
Improved systems and methods for collecting solar energy addressing each of these characteristics are desired.