To perform an I-V trace the system is used with a Keithley 2400 Source meter. To begin with the cell is connected in series with the Keithley. The two contacts of the cell are connected to the two auxiliary BNC ports in the side of the enclosure. If the cell has a front and back contact then the front contact is connected via the probe using the BNC to BNC cable. The back contact is placed on the vacuum chuck and connected using the BNC to spade connector cable attached to the back of the chuck. If the cell has two front contacts then both contacts are made using the probes using BNC to BNC cables. The outputs of these two auxiliary BNC connectors are then connected to the Input /Output ports of the Keithley. This is done by using the BNC to red/black plugs cables. The back of the cell is connected to the red input of the Keithley.


Figures 1 and 2, showing the connections to a cell for performing an IV trace

Now Benwin+ is started using the Keithley configuration. It should be ensured that the Keithley unit itself is set up correctly. If using RS232 communication use the following settings:

Baud rate : 19200

Bits: 8

Parity : None

Terminator: <CR+LF>

Flow control : None

Using the bias light utility a bias light can be applied to the cell, if required. Also under the utilities menu is the IV tracer utility. Opening this will open the main control window. The start and end voltage as well as the step size can be adjusted. The data collection settings can also be changed. Once all the parameters are set up a scan can be performed. When the scan has been done the software will display some statistics about the cell such as VOc and max power. In the event of an error where the software says it cannot calculate these values this simply means the cell is connected the wrong way round. Simply switch over the two inputs of the Keithley and try again. The file can then be saved for later analysis.