Low-cost LBIC System for Solar Cell Defect Identification by Modification of a 3D Printer

Defects buried within a solar cell greatly influence the power output and long-term operation of the cell. Laser beam induced current (LBIC) is a non-destructive characterization technique that can be used for the identification of invisible defects within a solar cell. Commercial LBIC instruments are highly expensive which limits their accessibility. In this project we have been developing a low-cost LBIC instrumentation system through the modification of a 3D printer. Our current system design accommodates three different laser sources with varying wavelengths in the near ultraviolet (UV), visible, and near-infrared (NIR) regions. We have developed in-house custom-built circuits to drive the lasers, to control the solar cell scanning, and to measure the laser induced output current from the cell. To effectively control the experiment and perform experimental measurements, a programmable logic device is utilized which communicates between the physical circuits and a graphical user interface (GUI) program. A custom mechanical housing has been designed for laser diode installation in place of the 3D printer’s filament extruder, and stage control is accomplished through the utilization of the printer’s original stepper motors. Such design modifications have allowed us to drastically reduce overall cost and bypass the need for expensive optics and stage control. We have also developed an open-source Python-based graphical user interface from scratch to control the experiment, as well as perform automated data acquisition. Our research project will enable a low-cost solution for laser induced defect analysis in solar cells for education, research, and commercial manufacturing of solar cells