Simulation of a-Si:H/c-Si heterojunction solar cells: From planar junction to local junction*

Abstract

In order to obtain higher conversion efficiency and to reduce production cost for hydrogenated amorphous silicon/crystalline silicon (a-Si:H/c-Si) based heterojunction solar cells, an a-Si:H/c-Si heterojunction with localized p–n structure (HACL) is designed. A numerical simulation is performed with the ATLAS program. The effect of the a-Si:H layer on the performance of the HIT (heterojunction with intrinsic thin film) solar cell is investigated. The performance improvement mechanism for the HACL cell is explored. The potential performance of the HACL solar cell is compared with those of the HIT and HACD (heterojunction of amorphous silicon and crystalline silicon with diffused junction) solar cells. The simulated results indicate that the a-Si:H layer can bring about much absorption loss. The conversion efficiency and the short-circuit current density of the HACL cell can reach 28.18% and 43.06 mA/cm2, respectively, and are higher than those of the HIT and HACD solar cells. The great improvement are attributed to (1) decrease of optical absorption loss of a-Si:H and (2) decrease of photocarrier recombination for the HACL cell. The double-side local junction is very suitable for the bifacial solar cells. For an HACL cell with n-type or p-type c-Si base, all n-type or p-type c-Si passivating layers are feasible for convenience of the double-side diffusion process. Moreover, the HACL structure can reduce the consumption of rare materials since the transparent conductive oxide (TCO) can be free in this structure. It is concluded that the HACL solar cell is a promising structure for high efficiency and low cost.

Evaluating the Practical Efficiency Limit of Silicon Heterojunction–Interdigitated Back Contact Solar Cells by Creating Digital Twins of Silicon Heterojunction Solar Cells with Amorphous Silicon and Nanocrystalline Silicon Hole Contact Layers

“…[ 20 ] If lateral carrier transport is considered in solar cells, multidimensional device simulation software should be employed. Silvaco Atlas accommodates this need and has been applied to optimize IBC solar cells, [ 21 ] design new SHJ solar cell structures, [ 22 ] and explore dopant‐free silicon heterojunction solar cells. [ 23 ] In SHJ solar cells and SHJ–IBC solar cells, carriers transport vertically and laterally.…”

Toward Efficiency Limits of Crystalline Silicon Solar Cells: Recent Progress in High‐Efficiency Silicon Heterojunction Solar Cells

“…In 2019, Huang et al have designed a Heterojunction of Amorphous silicon and Crystalline silicon with Localized pn structure (HACL). [106,107] Instead of a structure where the emitter and back-field layer cover the entire surface, the area of the emitter region covers ≈3% of the area of the wafer in HACL. This new design yields a higher J SC than conventional SHJ cells: 42.55 mA cm −2 for rear-emitter cells and 43.06 mA cm −2 for front-emitter cells.…”

“…Cu-grid electrodes [12,104,109] New silver finger design Multi-busbar, [99,100] smart wire, [101] interconnect-shingling [102] New architectures Patterning a-Si:H layer Local junction design [106] Hybrid solar cells Hybrid SHJ solar cells [108] the main passivation layer, deposited by a high hydrogen dilution plasma. This main passivation layer is denser than the buffer layer.…”

Untitled

“…However, the cell structures using HIT and IBC technologies are very complex and do not facilitate mass production. Our team proposed a new amorphous silicon/crystalline silicon heterojunction solar cell with localized p-n junction (a-Si:H/c-Si heterojunction with localized p-n structure, or HACL cell) [16][17][18] . The localized p-n junction can significantly improve the parasitic absorption loss of a-Si:H and reduce the recombination of photogenerated carriers in the emitter, and also maintain the high open-circuit voltage of the cell, while this cell structure is simplified compared to the HIT+IBC structure, which is convenient for mass production.…”