Graphene like materials in TCO/silicon Schottky junction solar cells

In this work a silicon based hybrid junction solar cell with transparent conductive oxide (TCO) as top contact and including a layer composed by 3-aminopropyltriethoxysilan (APTES) and soluble graphene oxide (GO) with the structure of TCO/AGO/Si (where the layer formed by APTES and GO is referred to as AGO) was fabricated and tested. The realized structure had the typical scheme of a metal-insulator-semiconductor silicon based solar cell where the conventional metal front contact was substituted with a ZnO:Al (AZO) transparent layer and a low-cost and easy-to-fabricate insulating layer (AGO) replaced the conventional interfacial SiOx layer. The analysis of the photovoltaic parameters allowed to put in evidence the beneficial effect of the fully transparent top contact as well as the role of the AGO interfacial layer. In particular, the measured external quantum efficiency of the AZO/AGO/Si solar cell reached values above 80% in the central part of the visible spectrum, with short circuit current of about 30mA/cm2, while the power conversion efficiency resulted more than two times higher than that of the device without the incorporation of the AGO layer. The coupling, for the first time at our knowledge, of TCO layer and a GO layer in a silicon based solar cell, opens the door for several applications in photovoltaic and other optoelectronic devices.