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8th World Conference on Photovoltaic Energy Conversion; 95-97, We present passivating contacts for silicon solar cells using an interfacial layer of SiO2 grown by immersion in hot HNO3 and in-situ doped layers of both polarities grown by plasma enhanced chemical vapor deposition (PECVD). The doped layers are crystallized and their dopants are activated by rapid thermal processing (RTP) with a temperature profile similar to the firing of screen-printed metallization pastes, hence we call them fired passivating contacts (FPCs). After RTP, we apply hydrogenation to passivate defects, using thermal release of hydrogen from a SiNx reservoir layer during hot plate annealing at 450°C. We find that the kinetics of the hydrogenation process is characterized by a fast process associated to the passivation of defect states at the Si/SiO2 interface and a slower process likely related to the hydrogenation of bulk defects that are formed during RTP in the floating zone wafers used in this experiment. Despite the issue with bulk defects, we test the suitability of the FPCs for solar cells by depositing n- and p-type layers on the textured front and on the flat rear of single-side textured wafers, respectively. After co-processing in a single RTP step, we apply the optimum hydrogenation conditions identified above. Using an ITO/Ag metallization made at low temperature to fabricate proof-ofconcept solar cells, we obtain efficiencies up 20.5%.

High-temperature compatible passivating contacts based on phosphorus doped polysilicon (poly-Si(n)) on a thin silicon oxide, employed on the rear side of bifacial n-PERT like solar cells provide an efficiency increase while being compatible with current photovoltaic manufacturing processes, including the metallization process. However, a simple and cost-effective method for poly-Si(n) deposition is still elusive. Herein, we demonstrate DC-sputtering as a scalable and single side technique for poly-Si(n) manufacturing. First, it is demonstrated how DC-sputtered poly-Si(n) can provide high passivation (iV(oc) > 730 mV) and low contact resistivity (rho(c) < 20 m omega cm(2)) when metallized by means of screen printing and firing through of Ag paste. Then, M2-sized bifacial n-PERT solar cells featuring the developed DC sputtered poly-Si(n) at the rear side and a homogenous front side B-emitter reaching a certified efficiency of 22.8% are demonstrated. Quokka simulations based on the developed DC sputtered poly-Si(n) indicate a potential up to 24.8% with an upward potential upon optimization of the front side emitter. This work highlights the feasibility of sputtered poly-Si(n) as an enabler for high-efficiency n-type solar cells.

We investigate bulk and interface recombination in crystalline silicon with p-type fired passivating contacts. These consist of a chemical oxide and an in-situ doped layer of SiCx with low carbon content. Following a rapid thermal annealing to activate the dopants in the SiCx layer, we observe the formation of bulk defect states close to one of the band edges at temperatures between 450 and 700 degrees C. At temperatures of 800 degrees C and above, these bulk defects are increasingly cured. At the same time, the surface passivation provided by the interfacial oxide is increasingly deteriorated at temperatures above 800 degrees C, eventually permitting the injection of a recombination current into the SiCx layer. Consequently, there is a trade-off for the effective minority carrier lifetime with an optimum between 800 and 830 degrees C. We develop a formalism that distinguishes recombination through shallow bulk defects from the recombination current at the surface in a plot of the effective lifetime tau(eff) over the ratio n/p.

Introduction Central line-associated bloodstream infections (CLABSI) remains a high risk for burn patients due to their compromised integumentary system. Additionally, identifying bloodstream infections secondary to a burn infection versus a central line remains a challenge. Literature review suggests multidisciplinary CLABSI bundles (MCB) demonstrate reduction of CLABSIs. This research looks at the use of a MCB compared to the application of the standard CLABSI bundle alone reduce CLABSI incidence and standardized infection ratios over the past two years in the Burn Center. We hypothesize a MCB will have sustained CLABSI SIR and incidence reduction over time. Methods Infection Prevention & Control CLABSI data collection on all burn patients pre-intervention (2017-2018) and post-intervention (2019-2020) were performed as a quality improvement project; IRB was not obtained. In addition to the CLABSI Bundle (optimal site, aseptic insertion, aseptic maintenance, timely removal, & education), MCB was also implemented in Qtr. 1, 2019. MCB includes necessity of line discussion during daily and multidisciplinary rounds, strategic blood culture collection upon admission/transfers for patients with existing central line, improved nursing and provider documentation of burn infection per CDC definitions, integration of CLABSI reviews in tiered Burn Quality Improvement Program, and universal zero CLABSI goal setting for RNs. Two-sample t-test will be used to compare results pre-intervention (2017-18) & post-intervention (2019-20). CLABSI incidence and standardized Infection ratio will be illustrated per year. Results The post-intervention CLABSI SIR data (M= 0.08, SD=0.11) significantly improved when compared to the pre-intervention CLABSI SIR data (M= 0.77, SD= 0.169), t(2)=4.72, p=0.02. The post-intervention CLABSI incidence data (M=0.5, SD=0.70) significantly improved when compared to the pre-intervention CLABSI incidence data (M=4.5, SD= 0.70), t(2)= 5.65, p= 0.01 Conclusions The combination of the CLABSI bundle with the MCB demonstrated favorable CLABSI SIR and incidence reduction, as literature suggests. Implementing multimodal, multidisciplinary interventions must be a priority for sustained CLABSI reduction. Considerations for future studies should measure length of catheter days, incidence of positive blood cultures on admission/transfers for patients with existing central lines, and incidence of burn infection rates with positive blood culture and an existing central line.