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In this work we compare experimental results of an industrial passivated emitter and rear cell (PERC) high volume pilot line production in the SolarWorld Innovations technology center with a simulation model based on 2D Sentaurus Device Simulations The PERC solar cell design shows in a well-controlled experiment a 1.1% absolute higher median efficiency compared to the aluminium back surface field (Al-BSF) solar cell reference group. We derive a calibrated simulation model by the characterization of cells and test structures. We show that the simulation model reproduces well the measured I-V data. In consequence this enables us to estimate the solar cell performance when an applied process or silicon wafer parameters will be changed for further optimization. In the second part of this study we investigate the impact of front and rear side recombination on the solar cell parameters by simulation and sensitivity analysis. We show that the quality of the local BSF underneath the local rear contacts has an important impact on the electrical solar cell performance.

The reaction of CuCl with WOCl3 at 400 °C leads to a mixture of Cu1−x[W2O2Cl6] (1) and Cu1−x[W4O4Cl10] (2) in form of black lustrous needles. Both compounds crystallize in space group C2/m with a = 12.7832(5) A, b = 3.7656(2) A, c = 10.7362(3) A, β = 119.169(2)° for 1 and a = 12.8367(19) A, b = 3.7715(7) A, c = 15.955(3) A, β = 102.736(5)° for 2. The structures are made up of WO2Cl4 octahedra. In the case of 1 two octahedra are edge-sharing via chlorine atoms to form pairs which are linked via the trans-positioned oxygen atoms to form infinite double strands . In the structure of 2 two of these double strands are condensed via terminal chlorine atoms to form quadruple strands . Like for all members of the Mx[W2O2X6] structure family (X = Cl, Br) nonstochiometry with respect to the cations M was observed. The copper content of 1 and 2 was derived from the site occupation factors of the respective structure refinements. For several crystals examined the copper content varied between x = 0.27 and 0.17 for 1 and x = 0.04 for 2. In both structures the oxochlorotungstate strands are negatively charged and connected to layers by the monovalent copper ions, which are tetrahedrally coordinated by the non-bridging chlorine atoms of the strands. The structure models imply disorder of the Cu+ ions over closely neighboured sites.

Black, needle shaped crystals of NbOBr2 were formed by reduction of NbOBr3 with InBr at 500 °C. It crystallizes isotypically to NbOI2 (monoclinic, space group C2, a = 13.833(4), b = 3.9079(6), c = 7.023(2) A, β = 105.026(10)°). The structure consists of NbO2Br4 octahedra, which are connected to layers . Nb atoms of edge sharing octahedra form Nb2 pairs with Nb–Nb distances of 3.144(5) A. Within corner-sharing octahedra alternating long and short Nb–O bonds are present, causing the polarity of the structure.