Introduction

Measurement system and method allowing to illuminate isolated areas of a solar cell by using a monochromatic light source of a given narrow band wavelength. By measuring the relative photocurrent produced locally and comparing with other measurements on multiple areas of the same cell it is possible to obtain the spatial homogeneity of electrical properties of the device.

Technical features

In a solar cell the higher the homogeneity of electrical properties, the higher the efficiency. To define this aspect it is possible to measure the spatial homogeneity of the photocurrent produced at different depth and over the whole surface of a solar cell, by using the relation between the wavelength of incident light and the absorption depth. For IR light the homogeneity of Back Surface Field all over the back surface of a cell: the better the homogeneity, the higher the voltage and efficiency of the device. The system is constituted by a light source matrix having a specific wavelength, by a grid that divides the solar cells in portions optically isolated one from each other and by electronic boards that make the measurement automatic by driving the single sources and acquiring the photocurrent generated by each single portion of the cell. Compared with other instruments for cell properties mapping, this system is fast, without moving parts, non disruptive and low cost.

Possible Applications

• Laboratory test for solar cells;
• manufacturing solar cells industry;
• measurement tools for solar cells producers
• optoelectronic devices producers.

Advantages

• Absence of moving parts;
• Fast measurement;
• Lower cost with respect to other instruments like photoluminescence possibility to be inserted in production lines;
• Device characterization at different depth;
• Possible integration with other diagnostic tools for solar cells.