Making Record-efficiency SnS Solar Cells by Thermal Evaporation and Atomic Layer Deposition

Tin sulfide (SnS) is a candidate absorber material for Earth-abundant, non-toxic solar cells. SnS offers easy phase control and rapid growth by congruent thermal evaporation, and it absorbs visible light strongly. However, for a long time the record power conversion efficiency of SnS solar cells remained below 2%. Recently we demonstrated new certified record efficiencies of 4.36% using SnS deposited by atomic layer deposition, and 3.88% using thermal evaporation. Here the fabrication procedure for these record solar cells is described, and the statistical distribution of the fabrication process is reported. The standard deviation of efficiency measured on a single substrate is typically over 0.5%. All steps including substrate selection and cleaning, Mo sputtering for the rear contact (cathode), SnS deposition, annealing, surface passivation, Zn(O,S) buffer layer selection and deposition, transparent conductor (anode) deposition, and metallization are described. On each substrate we fabricate 11 individual devices, each with active area 0.25 cm[superscript 2]. Further, a system for high throughput measurements of current-voltage curves under simulated solar light, and external quantum efficiency measurement with variable light bias is described. With this system we are able to measure full data sets on all 11 devices in an automated manner and in minimal time. These results illustrate the value of studying large sample sets, rather than focusing narrowly on the highest performing devices. Large data sets help us to distinguish and remedy individual loss mechanisms affecting our devices.United States. Dept. of Energy (SunShot Initiative Contract DE-EE0005329)Robert Bosch GmbH (Bosch Energy Research Network Grant 02.20.MC11)Alexander von Humboldt-StiftungUnited States. Dept. of Energy. Office of Energy Efficiency & Renewable Energy (Postdoctoral Research Award)Intel Corporation (PhD Fellowship

DESIGN OF RESIDENTAL SOLAR POWER MOUNTING SYSTEM

Small, residential solar power can be part of the solution to the energy crisis. However, there are very few options for a homeowner to purchase household solar mounting systems. To meet this need, a single solar panel ground mounting system has been designed that is functional, economical and easy to install. The design includes a base with a detachable center square pole and an angle adjuster allowing residential use throughout the US. The retail price is less than $1,500 and has easy to follow instructions for installation

Green Building Designs and Renovations for the Worcester Youth Center

This group worked with the Worcester Youth Center to devise a plan for their derelict warehouse. The space is a safety burden to the Center and the youth. Through surveys and research analysis the group developed two designs to implement a recreation center that sets an example to the community by incorporating green aspects into its construction. This project has inspired the Board of Directors to create a committee dedicated to accomplish this task