Crystalline silicon (c-Si) heterojunction (HJT) solar cells are one of the promising technologies for next-generation industrial high-efficiency silicon solar cells, and many efforts in transferring this technology to high-volume manufacturing in the photovoltaic (PV) industry are currently ongoing. Metallization is of vital importance to the PV performance and long-term reliability of HJT solar cells. In this review, we summarize the development status of metallization approaches for high-efficiency HJT solar cells. For conventional screen printing technology, to avoid the degradation of the passivation properties of the amorphous silicon layer, a low-temperature-cured (< 250 ℃) paste and process are needed. This process, in turn, leads to high line/contact resistances and high paste costs. To improve the conductivity of electrodes and reduce the metallization cost, multi-busbar, fine-line printing, and low-temperature-cured silver-coated copper pastes have been developed. In addition, several potential metallization technologies for HJT solar cells, such as the Smart Wire Contacting Technology, pattern transfer printing, inkjet/FlexTrailprinting, and copper electroplating, are discussed in detail. Based on the summary, the potential and challenges of these metallization technologies for HJT solar cells are analyzed.

Herein, an ultrafast random‐pyramid texturing process is proposed for monocrystalline silicon (mono‐Si) solar cells by combining metal‐catalyzed chemical etching (MCCE) and the standard alkaline texturing process. Namely, large numbers of artificial defects are introduced on the wafer surface in 3 min by MCCE; therefore, the process duration of alkaline texturing is largely shortened from 420 s for the as‐cut wafer to 180 s for the wafer with artificial defects due to its high surface reactivity. Moreover, those tiny artificial defects are apt to form small pyramids, resulting in a better light‐trapping performance. As a demonstration, the passivated emitter rear contact solar cell with ultrafast random pyramid texture achieves a power conversion efficiency of 23.02%. Therefore, such a cost‐effective ultrafast texturing strategy can open a promising new route toward the mass production of high‐efficiency industrial mono‐Si solar cells.

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Currently, a bifacial passivated emitter and rear cell (bi-PERC) is the mainstream solar cell technology in the photovoltaic industry. In this paper, we studied the influence of rear pyramid morphologies with different slope angles on the overall optical and electrical properties of bi-PERC solar cells. With the help of simulations, we first obtained a macro understanding of the influence of rear surface morphologies on the absorbed and lost photon current density of bi-PERC solar cells. In practice, both the optical and passivation properties of solar cells were affected by the rear surface morphology. A smoother rear surface was proven to be favorable for rear passivation and unfavorable for rear-side light trapping. Rear surface morphologies also contributed to back-reflection and back-scattering effects that influenced the front-side light trapping. Consequently, the highest front-side average efficiency of 22.86%, with an average bifaciality factor of 76.02%, was achieved for the bi-PERC solar cells using a modified acidic polishing process. Furthermore, the calculated equivalent bifacial efficiency showed that a maximum value of 29.82% could be obtained at an albedo value of 40%. Finally, we further evaluated the optical performances of the corresponding single-cell modules.