Current-voltage characteristics of silicon based solar cells in the presence of cracks: MD simulations

SDVSSV Siruvuri and PR Budarapu and M Paggi, SEMICONDUCTOR SCIENCE AND TECHNOLOGY, 37, 025011 (2022).

DOI: 10.1088/1361-6641/ac3374

The presence of micro-cracks in solar cells hinders the movement of charges leading to charge accumulation around the crack surfaces. Cracks grow during real-time operation and also new cracks will be formed, leading to further charge accumulation. In this study, the influence of cracks on the movement of charges and hence the current-voltage characteristics of silicon based solar cells is investigated through molecular dynamics simulations. Simulations are performed considering a domain of dimensions 260.64 angstrom x 222.63 angstrom x 43.44 angstrom with five different cases: (1) without any initial defects, (2) an edge crack, (3) a center crack, (4) two angled edge cracks and (5) two oblique cracks from a circular crack at the center of the domain, considering a time step of 1 fs. Charges of the atoms at a given time instant are estimated after charge equilibration. The electric current, voltage, and power are estimated based on the charges. As the crack starts propagating, the charge fluctuations of a group of atoms around the crack tip are observed to be in the range of -9x10(-3) e to -6x10(-3) e, where the highest fluctuation is noticed in case of angled edge cracks. The electric current for the same atoms is found to be fluctuating between -0.02 nA and -0.098 nA, peak fluctuations observed in the case of the edge crack. Similar ranges of charge and current without any initial crack are found to be: 0 x 10(-3) e and 3 x 10(-3) e, and 0 nA and 0.01 nA, respectively. This confirms that the presence of cracks can hinder the charge flow. Furthermore, the peak voltage estimated between two groups of charges: near and far away from the crack tip is found to be 1.24 x10(-22)

Return to Publications page