Identification of Design Aspects and Critical Design Parameters for Low-Cost, High-Efficiency Solar Cells
Critical design aspects or fundamental design parameters for a low-cost, high-efficiency solar cell are identified below. Preliminary studies performed by the author on solar cell technology reveal that contact resistance plays a key role in the conversion efficiency of the solar cell, regardless of device type. Contact resistance losses occur at the interface between the solar cell and the metal contact. Contact resistance is the most critical performance parameter of the solar cell. Major performance degradation from the increased series resistance is due to the contact resistance that will ultimately degrade the conversion efficiency of the solar cell, regardless of the solar cell design.
For silicon-based cells, the fundamental recombination limit, the effects of diffusion gradients, resulting electric field loss, and contact insertion loss can degrade conversion efficiency of the cell. It is important to point out that the contact surface integrity is of critical importance, if longevity or ultra-long operational duration is the principal design requirement.
For point-contact solar cell devices, device geometrical parameters, surface recombination velocity, bulk lifetime, idealized thermodynamic limit, and emitter saturation currents play key roles, if high efficiency and ultra-high reliability are the fundamental design requirements.
For low-cost, high-efficiency PERC solar cells, fast processing time, mass production capability, low processing cost and low-cost, efficient patterning scriber technology are important. The photolithography process is the most expensive process and must be avoided, if minimum fabrication cost is the principal design requirement.
Fundamental design requirements for high-efficiency solar cells include good passivation of both cell surfaces with high-quality dielectric layers such as silicon oxide and silicon nitride, thin wafers, and mechanical abrasion technology to pattern the rear contact on the dielectric layers instead of an expensive photolithography process. The mechanical scriber process  shows great potential for low-cost commercial solar power module applications. Now some potential solar cells capable of providing both the low cost and high efficiency will be described in more detail.