The main reason for efficiency losses of solar panels is Potential Induced Degradation (PID). Regardless of the type of PV system, the PIDbox of Ilumen regenerates the cells affected by PID.
The most common PV systems are mono- and polycrystalline silicon solar panels. Silicon is a semiconductor that is produced in two variants, the p-type with positive charge carriers and the less common n-type with negative charge carriers. The difference between the two types has its origin in the doping process during crystallization. While for the p-type boron is used as the dopant, phosphorus is added to the n-type silicon ingots.
Nowadays especially p-type solar panels are installed on our houses. However, higher yield can be obtained by n-type panels. In particular Sunpower and BenQ sell this latter type of panels since a long time. Also n-type panels suffer from Potential Induced Degradation.
While for p-type crystalline silicon solar panels a high negative voltage is harmful, a high positive voltage is experienced as harmful in the n-type panels. (Fig 1).
Fig 1: p- and n-type solar panel voltage
When a high positive voltage is applied to n-type silicon crystalline solar panels, a leakage current origins from the cells to the earth (Fig 2). As a result, over time a negative charge is left on the front surface of the solar cells. This negative charges will activate the surface transistor, attracting positive charge carriers to the front surface where they recombine with electrons and are lost. These charge carriers will therefore not contribute to the conduction of the solar cells which results in efficiency decreases.
Fig 2: The degradation process of n-type solar panels
Source: SunPower Discovers the ‘Surface Polarization’ Effect in High Efficiency Solar Cells
The PIDbox is compatible with both p-type and n-type solar panels. For this latter type of panels a slightly modified version of the PIDbox needs to be integrated with respect to the more ‘standard’ p-type of solar panels. Installing a PIDbox results in an efficiency increase of the PID affected solar cells. Moreover the lifetime of the PV system will be extended. The PIDbox can also be easily connected to the thin film solar panels.