Rear contact silicon solar cells with a-SiC_x:H based front surface passivation for near-ultraviolet radiation stability

摘要

Surface recombination (due to dangling bonds) and lower absorption (due to the low absorption coefficient of silicon (Si)) are the major hindrances in silicon-based photovoltaic (PV) devices. To overcome this, numerous complex texturing schemes are projected to enhance the light trapping. However nanostructured cells are not efficient due to the large surface to volume ratio which enhances surface recombination. Thus, the nanostructured cells require additional passivation scheme to mitigate the recombination losses. Here, we have designed a nontextured, 15% efficient, amorphous silicon carbide hydrogenated (a-SiCX:H) passivated, 10-mu m thick rear contact Si solar cell device. Considerable reduction in photo reflectance is obtained in the near ultraviolet (UV)/visible spectral region together with near UV stability at higher surface recombination velocity (SRV). External quantum efficiency (EQE) 90% is achieved by the a-SiCX:H based device (within the wavelength spectrum of 480-620 nm). Improvement in spectrum response give rise to 28.1 mA cm(-2) short circuit current density (J(SC)). Further, the performance of aSiC(X):H passivated device is compared with a conventional dielectric anti-reflective coating (ARC) and high-low junction-based surface passivation techniques. Results indicate that the presence of a-SiCX:H reduces the hole concentration near the front surface which eventually decreases the surface recombination. Highly efficient and reliable solar cells can be achieved by the design schemes reported in this paper, which balance both the photonic and electronic effects together.