Concentrating microlens array mounted on an InGaP/GaAs/Ge solar cell for photovoltaic performance enhancement

We present a technique of mounting a microlens array (MLA) on a solar cell to serve as both an incident light manipulator and an encapsulation layer. The cylindrical MLA with a uniform element is fabricated through micromachining processes. The MLA mounted on a triple-junction InGaP/GaAs/Ge solar cell enhances the optical efficiency and the resultant photovoltaic performance, which is mainly attributed to the solar light micro-concentration effect and the elimination of optical shading. The MLA effect is maximized under the optimal mounting condition, resulting in the 17.2% and 18.5% increases in photocurrent and power conversion efficiency (PCE), respectively, in comparison with those of the bare glass-covered cell. The efficiency of the MLA-encapsulated solar cell remained almost unchanged for a long time.

► A microlens array (MLA) was mounted on a solar cell as an encapsulation layer.
► The uniform cylindrical MLA was fabricated via simple micromachining processes.
► The MLA eliminated optical shading through the incident solar light manipulation.
► The light concentration primarily enhanced photovoltaic performances of the cell.
► A 18.5% increase in efficiency over that of the bare glass-covered one was achieved.