The basic culminating process in a solar cell generates a hole-electron pair on effect of sunlight, which is separated by a potential barrier (such as p-n junction), and hence manages to induce a current flow for production of clean electricity. Now in practical scenarios these charges become trapped by defects in bulk materials and their interfaces, and hence the overall performance of the cell is reduced.
And in bid to rectify and rather improve upon this deficient characteristic of solar cells, a team led by Oak Ridge National Laboratory’s Jun Xu has ingeniously contrived a new and advanced technology. This technology calls for a revamped solar structure consisting of n-type nanocones surrounded by a p-type semiconductor. The n-type nanoncones are composed of zinc oxide and serve as the junction framework and the electron conductor. The p-type matrix is made of polycrystalline cadmium telluride (CdTe) and serves as the primary photon absorber medium and hole conductor (an electron hole is the conceptual and mathematical opposite of an electron). This total improved mechanism of the PVs was actually able to enhance the light-to-power conversion efficiency by at least 80 percent.
The tests showed that these effectively composed solar cells exhibited 3.2 percent efficiency, in comparison to 1.8 percent efficiency of conventional planar structure of the same materials.
According to team leader, Jun Xu:
We designed the three-dimensional structure to provide an intrinsic electric field distribution that promotes efficient charge transport and high efficiency in converting energy from sunlight into electricity. The important concept behind our invention is that the nanocone shape generates a high electric field in the vicinity of the tip junction, effectively separating, injecting and collecting minority carriers, resulting in a higher efficiency than that of a conventional planar cell made with the same materials.
