Influence of Solder Pads to PERC Solar Cells for Module Integration

AbstractThe majority of screen printed solar cells has silver pads at the rear side to enable soldering for the module manufacturing. The pads increase the recombination at the silicon/metal interface due to the absence of a back surface field (BSF) at the solder pads. This reduces the efficiency of full-area Al-BSF solar cells. For passivated emitter and rear cells (PERC), a large area fraction of the rear side is covered with the passivation layer. When using specially designed Ag pastes for the rear side of PERC cells, the passivation of this layer is maintained, and the rear recombination is reduced.A comparison of solar cells with and without solder pads confirms that there is no loss in solar cell performance, both cell types achieve an efficiency of 19.6%. We investigate the influence of solder pads to PERC solar cells by calculating the effective rear surface recombination. The calculations confirm that there is a loss in open circuit voltage of less than 2mV due to the solder pads.A 54-cell PERC PV module is manufactured. The cell-to-module loss reveals that the module process is still to be optimized. Comparable modules made from 9 solar cells lost less than 1% relative in all J-V parameters after a 1000h damp-heat test

Comparative transcriptomic and proteomic signature of lung alveolar macrophages reveals the integrin CD11b as a regulatory hub during pneumococcal pneumonia infection

IntroductionStreptococcus pneumoniae is one of the main causes of community-acquired infections in the lung alveoli in children and the elderly. Alveolar macrophages (AM) patrol alveoli in homeostasis and under infectious conditions. However, the molecular adaptations of AM upon infections with Streptococcus pneumoniae are incompletely resolved.MethodsWe used a comparative transcriptomic and proteomic approach to provide novel insights into the cellular mechanism that changes the molecular signature of AM during lung infections. Using a tandem mass spectrometry approach to murine cell-sorted AM, we revealed significant proteomic changes upon lung infection with Streptococcus pneumoniae.ResultsAM showed a strong neutrophil-associated proteomic signature, such as expression of CD11b, MPO, neutrophil gelatinases, and elastases, which was associated with phagocytosis of recruited neutrophils. Transcriptomic analysis indicated intrinsic expression of CD11b by AM. Moreover, comparative transcriptomic and proteomic profiling identified CD11b as the central molecular hub in AM, which influenced neutrophil recruitment, activation, and migration.DiscussionIn conclusion, our study provides novel insights into the intrinsic molecular adaptations of AM upon lung infection with Streptococcus pneumoniae and reveals profound alterations critical for effective antimicrobial immunity