Silicon Tandem Solar Cell under Advanced Materials for Next- generation Energy Efficient Devices (D-NEED)

Simulation and optimization of single junction a-Si:H solar cell, and for a-Si:H/c-Si tandem solar cells was carried out. Micro-texturing and anti–reflection coating, ARC (silicon nitride) deposition on silicon wafers by PECVD has been performed to reduce the reflection (~7%) from top surface of silicon wafers.ARC (silicon nitride) deposition on 156mm x 156 mm c-silicon wafers has been completed. Single Junction c-Silicon solar cells have been fabricated (Efficiency=11.3%) (Fig. 1). The efficiency is low due to high series resistance in the cells. Neglecting series resistance, estimated efficiency is ~15.5%. Efforts are made to improve the process. Measured I-V curve under AM 1.5G at BHEL, Gurgaon shown in Fig. 2. Process for deposition of indium-tinoxide (ITO) thin films by sputtering for transparent conducting top contact of amorphous silicon top cell of tandem configuration was completed.

Extracted solar cell parameters:

Parameter Value
Open Circuit Voltage 0.5460 V
Short Circuit Current 0.2290 A
Peak power 0.090 W
Voltage at P peak 0.4580 V
Current at P peak 0.1980 V
Fill factor 0.73
Cell efficiency 11.3%

Fig. 1: Fabricated solar cell

Fig. 2: Measured I-V curve under AM 1.5G at BHEL, Gurgaon