Semi‐transparent plastic solar cell based on oxide‐metal‐oxide multilayer electrodes

Semi‐transparent plastic solar cells are currently highly attractive for their potential as the most prominent components for building‐integrated photovoltaics. However, the power conversion efficiency (PCE) of semi‐transparent plastic solar cells still lags behind due to the lack of a suitable transparent top electrode which can be easily fabricated. Here, we demonstrate high performance semi‐transparent plastic solar cells by introducing an oxide‐metal‐oxide (OMO) multilayer composed of MoO3 and Ag as a transparent top electrode. Because the conductivity of the OMO electrode is governed by an intermediate Ag layer sandwiched between 2 MoO3 layers, the PCE also strongly depends on the thickness of the intermediate Ag layer in the OMO electrode. By controlling the thickness of Ag layer, we obtained various PCE values from 4.5% with ~50% maximum transparency in the visible region to 9.1% with ~5% maximum transparency in the visible region. In addition, in order to get closer to practical application, 2 sizes of mini‐module devices were fabricated on a larger (10.0 cm × 10.0 cm) substrate for outdoor operation and small‐sized (7.0 cm × 5.0 cm) substrates for indoor operation were demonstrated using 3 materials of different color. High efficient semi‐transparent plastic solar cells based on oxide‐metal‐oxide were demonstrated from a single unit cell device to 10.0 cm × 10.0 cm sized mini‐module devices. The semi‐transparent solar cell which has a maximum transparency of 25% in visible region yielded a power conversion efficiency of 8.4%.