Solar simulator and I-V measurement system for large area solar cell testing

Abstract

This paper describes the design, operation and use of a PC controlled test setup designed specifically to measure the I-V characteristics of large area solar cells operated under simulated solar irradiation for the purpose of testing their quality and determining their optimal operational points for maximum electrical output. The project included design of a wafer-prober and solar-simulator combination so that large area wafers (up to 8 inch in diameter) could be tested at/up to AM1.5 standard solar insolation. Rather than simply looking at the short circuit current and the open circuit voltage of a solar cell, our system measures its full I-V characteristics while the cell is irradiated with an artificial light source which simulates the solar radiation. The artificial sunlight is created by combining metal-halide and quartz halogen light sources. The measurement is done in an automated way by employing standard bench top GPIB instruments interfaced to a PC and by using the function generator as a stepped voltage source. High test currents needed by the large area solar cell are provided by a unity gain DC power amplifier driven by the function generator. A Mathematica code written creates plots of measured I-V data and determines the maximum electrical power output of the cell as well as the series resistance, the parasitic effect most effective in lowering maximum power and efficiency.