Daming Chen

20.8% PERC Solar Cell on 156 mm × 156 mm P-Type Multicrystalline Silicon Substrate

Passivated emitter and rear solar cells (PERC) on the p-type multicrystalline silicon substrate have become the focus of recent laboratory and industrial-based research because of its promising mass production perspective. This paper presents the most recent studies on PERC solar cells and reveals the realization of a world record efficiency of 20.8% PERC solar cell fabricated with screen printing technology on 156 mm × 156 mm multicrystalline substrates. To further increase cell efficiency, an optical loss analysis was conducted, which shows that the current loss due to the nonoptimum light trapping dominates the overall optical loss. Based on the analysis, an efficiency of 21.3% is achievable in the near future with further optimization.

335Watt world record P-type mono-crystalline module with 20.6 % efficiency PERC solar cells

The objective of this experiment was to optimize module technologies to obtain the lowest price per Watt peak (

Al-alloyed local contacts for industrial PERC cells by local printing

/Wp) ratio and the maximum power output of a flat-plate module for a given number of high efficiency solar cells. Using p-type mono-crystalline Cz square silicon wafers, 156 mm × 156 mm solar cells with a passivated emitter and rear local contacts (PERC cells) were fabricated with an average efficiency of 20.6 %. The module includes half-cells for low interconnection losses, as well as a novel light-trapping scheme including Light Capture Ribbon (LCR) and a structured Light Reflective Film (LRF) between cells combined with an optimized large cell gap. The module achieves a new world record with a peak power output of 335.2 W in Sep. 2014, demonstrating that a large Cell-to-Module (CTM) factor, in this case greater than 1.11, can be achieved with new light trapping and low resistance connection technologies.

20.8% efficient PERC solar cell on 156 mm×156 mm p-type multi-crystalline silicon substrate

In this paper, a detailed investigation of the Al-alloyed local rear contacts for industrial PERC cells is presented. Three types of voids and their influences to PERC cells are evaluated with 2D numerical device simulations. By a detailed study of the formation mechanism of local contacts, an effective method of two-step metallization is proposed to suppress the generation of voids. In step 1, the Al paste is locally printed to limit the lateral diffusion of Al into Si during the firing process. In step 2, a full-area metallization with low temperature firing is applied to connect all the rear local Al contacts. With this method, a clear decrease of the void density after an industrial firing process is demonstrated. Nearly 0% voids rate can be achieved if the design width of the Al contact is small enough. This can prevent the recombination of minority carriers at the rear side, and contribute to Voc over 666 mV. Average cell efficiency of 20.26% and best efficiency of 20.50% are achieved in batch run in a pilot line. With advanced module technologies, a best module power of 326.3 Wp was achieved for a 60-cell-based module and independently confirmed.

Effect of carrier-induced hydrogenation on the passivation of the poly-Si/SiOx/c-Si interface

P-type multi-crystalline passivated emitter and rear solar cells (PERC) become the focus of recent laboratory and industrial base research due to its promising mass production perspective. This paper presents the most recent works on PERC solar cells and reveals the realization of a world record efficiency of 20.8% PERC solar cell fabricated with screen printing technology on 156 mm × 156 mm multi-crystalline substrates. To further increase the cell efficiency, an optical loss analysis was conducted, which shows that the current loss due to the poor light trapping dominates the overall optical loss. Based on the analysis, an efficiency of 21.3% is achievable in the near future with further optimization.

Development of High-efficiency Industrial p-type Multi-crystalline PERC Solar Cells with Efficiency Greater Than 21%☆

In the progress made in understanding carrier-induced degradation and regeneration in p-type mono and multi silicon solar cells, it was implied that hydrogen passivates certain defects during illuminated anneals at temperatures between 150-350°C. However, there are only few reports on the effect of carrier-induced regeneration (CIR) in n-type material. In this work, we apply a CIR treatment on samples structured as poly-silicon/tunnel oxide/n-type CZ. We present evidence suggesting that hydrogen passivation plays an important role in the regeneration process, and that improvement does not occur in the Si bulk but mainly at the Si/SiOx interface. For n-type poly, the Si/SiOx interface improves at temperatures of 250°C and above regardless of illumination and H-containing dielectric layer, and the rate of improvement is merely accelerated by illumination. For p-poly, the Si/SiOx interface is only stable in our experiments if the H-containing dielectric layer is present during CIR.