Screen printed metal contacts to Si solar cells — Formation and synergistic improvements
Silicon solar cell technology has advanced by improvements to all aspects of cell design including metallization. Improvements to metal contacts have been synergistic with other cell improvements such as passivation, lightly doped emitters, and boron doped emitters. This paper briefly recounts the history of c-Si PV metallization technology and its synergy with other cell technologies. It concludes with a perspective on various metal contact mechanisms.
POCl3 diffusion for industrial Si solar cell emitter formation
POCl3 diffusion is currently the de facto standard method for industrial n-type emitter fabrication. In this study, we present the impact of the following processing parameters on emitter formation and electrical performance: deposition gas flow ratio, drive-in temperature and duration, drive-in O2 flow rate, and thermal oxidation temperature. By showing their influence on the emitter doping profile and recombination activity, we provide an overall strategy for improving industrial POCl3 tube diffused emitters.
Experimental study on bond behavior between high-strength grout and deformed steel bars
Abstract Engineers use high-strength grout to connect precast concrete members for its low shrinkage and good fluidity. This paper designed 87 central pull-out specimens using the control variable method to investigate the influence of factors on the rebar-grout bond property such as compressive strength, steel grade, bar diameter, transverse stirrups, and bond length. The test result showed that improving grout compressive strength (85.8 MPa–122.7 MPa) cannot improve the bond strength, which was different from the previous conclusions of concrete pull-out tests. Simplified formulas were presented for calculating the characteristic values of bond strength, residual strength, peak slip, and relative slip of load-holding platform based on parameter analysis. Then, a constitutive model was proposed to predict the full-range bond stress-slip curve of high-strength grout and steel bar specimens from bearing to failure. Finally, FEA models were established to evaluate the applicability and accuracy of the constitutive model.