Hemispherical-shell-shaped organic photovoltaic cells for absorption enhancement and improved angular coverage

Abstract

A hemispherical shell shape is proposed for an organic photovoltaic cell structure, aiming at enhancing both light absorption and angular coverage. Three-dimensional finite element analysis method is used to study the absorption spectra within the hemispherical-shell-shaped active layer. The study reveals that the proposed structure can result in 66% and 36% of absorption improvements compared to a flatstructured device when the incoming light is transverse electric (TE)- and transverse magnetic (TM)-polarized, respectively. It is also learned that the proposed hemispherical shell structure has absorption improvement as high as 13% (TE) and 21% (TM) when compared to the previously reported semicylindrical shell structure. The angular coverage of the proposed structure is improved as well, reaching 81 deg (TE) and 82 deg (TM), which becomes quite useful for the wearable electronics applications where the incidence angle can vary in a random manner. These improvements can be attributed to better light coupling and guiding through the active layer made possible by the hemispherical shell shape of the device.