2D-Modeling and Development of Interdigitated Back Contact Solar Cells on Low-Cost Substrates

Abstract

Two-dimensional numerical simulations were performed to derive design rules for low-cost, high-efficiency interdigitated back contact (IBC) solar cells on a low-cost substrate. The IBC solar cells were designed to be fabricated using either the conventional screen printing or photolithography metallization processes. Bulk lifetime, bulk resistivity, contact spacing (pitch), contact opening width, recombination in the gap between the p + BSF and n + emitter, and the ratio of emitter width to pitch have been used as key variables in the simulations. It is found that short circuit current density (Jsc) is not only a strong function of the bulk lifetime but also the emitter coverage of the rear surface. Fill factor (FF) decreases as the emitter coverage increases because the majority carriers need to travel a longer distance through the substrate for longer emitter width. The simulated IBC results were compared with those for conventional screen printed solar cells. It was found that the IBC solar cell outperforms the screen printed (SP) solar cell when the bulk lifetime is above 50 μs due to higher Voc and Jsc, which suggests that higher performance can be realized on low-cost substrates with the IBC structure.

Numerical simulation of the impact of design parameters on the performance of back-contact back-junction solar cell

“…Renshaw et al [8] reported the η trend as a function of doping peaks for front surface field (FSF), back surface field (BSF) and emitter. Kim et al [9] studied some FOM as a function of geometrical parameters. In both works, FOM trends are evaluated for different surface recombination velocities (SRV) and bulk lifetimes.…”

All-back-contact ultra-thin silicon nanocone solar cells with 13.7% power conversion efficiency

“…For thick Si solar cells with the all-back-contact design, the pitch is normally 4400 mm, which allows less complicated fabrication processes such as screen-printing of metal contacts [38][39][40] . Previous studies have found that the fill factor (FF) was the only parameter that depended on the pitch in thick Si solar cells 41,42 . We, however, found that the J SC as well as the FF was closely dependent on the pitch in thin Si solar cells.…”

Optimization of interdigitated back contact silicon heterojunction solar cells by two-dimensional numerical simulation

“…1, J SC can be increased and the efficiency will be enhanced to 23.8%. Also the dimension of pitches, total of p-plus n-strips, can be optimized, where for traditional diffused IBC cells, the cell efficiency increases by 10% as pitch dimensions decreases from 1.7 mm to 600 μm [6]. Similar trends should also be valid for IBC-SHJ solar cells.…”

“…In this paper, we use "Sentaurus Device" [5], which is a simulator from software package Synopsys TCAD. Sentaurus Device is extensively used for modeling opto-electronic devices, and it is well suitable for modeling solar cells [6]. The latest version includes complex defect models allowing the simulation of devices which include amorphous silicon.…”