An example of a representative Al O PERC

An example of a representative Al2O3 PERC cell (sample A) measured by illumination-Voc is shown in Fig. 8, where the sample was tested before light-induced degradation (LID). The series resistance (Rs) of the industrial Al2O3 PERC cell is shown in Table 1, calculated according to Meier׳s method [4]. This calculation method is based on the measurement of Rs components in a sub-cell (the measurement array), shown as key measurement in Table 1. The resistance in the different regions of the sub-cell array was measured by the grid resistance tester, while the specific contact resistance was measured by the grid resistance tester based on the transmission line model (TLM) method [5]. In addition, Table 2 provides the basic information of the design pattern of the front Ag contact, which can support the calculation of Table 1. The detailed interpretation of the calculation results can be found in Ref. [1].
Acknowledgements The research work is based on the China-Finland International R&D Cooperation project “Improved cost-efficiency in crystalline silicon solar order Embelin through Atomic Layer Deposited Al2O3”, Project No. 40843 (Chinese Project No. S2013GR0622), 2013.05-2016.05. The work has been partially funded through the European Research Council under the European Union’s FP7 Programme ERC Grant Agreement No. 307315.
Data The dataset of this article provides additional information to Ref. [1]. PERC cell performances are reported in Table 1, the recombination as a function of the distance from both front and rear side is reported in Figs. 1, 2. The roadmap to PERC technology to 24% at an industrial level is shown in Table 2.
Experimental design, materials and methods PC2D simulations were performed to confirm the effect of J02 on the current industrial PERC cell performance, and the results are reported in Table 1. The detailed parameters settings can be found in Table 8 and Fig. 21 in Ref. [1]. The data show that the cell efficiency will gain 0.04% with J02 decreasing from 1·10−9 to 1·10−10Acm−2, which is mainly related to the gain in fill factor (0.13%). The series resistance (Rs) and the back surface recombination velocity (BSRV) and their relation with rear side metallization geometry were calculated for a point contact array geometry for the rear local contacts, as a function of the rear contact fraction and pitch (Fig. 1). The calculations are based on Fisher׳s and Plagwitz׳s model [6–9]. The data show that rear point or segment local contact arrays give lower total series resistance and thus lower BSRV with lower contact fraction. A representative example of the cumulative photo-generation and recombination as a function of the distance from the Si front surface is shown in Fig. 2. The data were simulated by PC1D Version 5.9 and it can be seen that the cumulative photo-generation profiles among different front n+ emitters with different front surface recombination velocities (FSRV) coincide. Note that the data can also be used to calculate the collection efficiency along the depth from the front Si surface, as the collection efficiency is the ratio between the cumulative recombination and cumulative photo-generation. A roadmap for industrial PERC cell technology to achieve efficiency up to 24% is shown in Table 2, which is based on the simulation data presented above and on the results on cell efficiency loss mechanisms presented in Ref. [1]. In particular, the recombination losses analysis was carried out with PC1D and PC2D simulations.
Acknowledgements The research work is based on the China-Finland International R&D Cooperation project “Improved cost-efficiency in crystalline silicon solar cells through Atomic Layer Deposited Al2O3”, Project No. 40843 (Chinese Project No. S2013GR0622), 2013.05-2016.05. The work has been partially funded through the European Research Council under the European Union’s FP7 Programme ERC Grant Agreement No. 307315.