High voltage bifacial amorphous Si quintuple-junction solar cells for IoT devices

Abstarct A bifacial amorphous Si quintuple-junction solar cell was proposed as a power source for IoT devices. Conventionally, interconnection using laser processing has been widely adopted in consumer devices using solar cells as a power source in order to increase the operating voltage, but in this paper, we propose a method to make the output voltage 3 V or more by quintuple-junction. First, after describing the necessity of using the bifacial structure, a simple theoretical discussion on the layer thickness of each cell was made. In addition, a-SiOx:H/a-SiOx:H/a-Si:H/a-SiOx:H/a-SiOx:H quintuple-junction solar cells were fabricated by plasma CVD method. As a result, a very high open circuit voltage of 3.4 V was demonstrated under LED light illumination.