Optoelectronic performance of a modified nanopyramid solar cell

Abstract

The optical and electrical characteristics of modified nanopyramid grating silicon solar cells (SCs) are numerically reported and analyzed. The modified grating SC consists of an upper tapered nanopyramid and lower nanorectangular parts. The geometrical parameters of the proposed design are tuned to maximize the optical absorption and hence the ultimate efficiency. The finite-difference time-domain and finite-element methods are utilized via Lumerical software packages for studying the optoelectronics performance of the suggested design. In this investigation, short-circuit current density (Jsc), optical generation rate, open-circuit voltage (Voc), electrical fill factor, and electrical power conversion efficiency (PCE) are calculated thoroughly. Moreover, the effects of the doping concentration and carrier lifetime on the device performance are also studied. The modified design provides an optical ultimate efficiency of 40.93% and optical Jsc of 33.49 mA/cm2, respectively, with an improvement of 28.3% over the conventional nanopyramid SC. This enhancement is due to the ability of the grating sidewalls to trap more light through the active layer. Additionally, the spacing between the adjacent nanopyramid structures can exhibit microcavity resonance, which contributes to light broadband absorption improvement. The p-i-n axial doping of the suggested SC exhibits Voc of 0.57 V, Jsc of 28.42 mA/cm2, and PCE of 13.3%, which are better than the Voc of 0.559 V, Jsc of 19.6 mA/cm2, and PCE of 8.95% of a conventional nanopyramid SC.