A method of temperature evaluation in the p-njunction area of nanoheterostructure cells converting laser or solar radiation has been proposed and elaborated. It is valid in any operational regime, in particular, at the maximum power point of the current-voltage characteristic. In the method, fast switching of a photovoltaic cell from maximum generated power to an open circuit regime is carried out and the open circuit voltage is measured immediately (within about 1 ms), so that this value becomes to be an indicator of the p-n junction temperature. Temperature control on any heated element of a photovoltaic module gives the means for determining the open circuit value at ambient temperature. Comparing it with that measured after switching-off a load allows calculating the p-n junction overheating temperature.
The investigations are carried out in the frame of Megagrant № 14.B25.31.0020.