Artificial Enhancements and Reductions in the PV Efficiency

The researcher is under great pressure to improve the conversion efficiency of photovoltaic (PV) devices. This paper addresses methods of artificially enhancing or reducing the efficiency with respect to a given set of standard reference conditions. Artificial efficiency improvements can be caused by measurement procedures, the data acquisition system, device processing, and the definition of what the standard reference conditions are for a given device. Procedural methods of enhancing the efficiency include applying a static charge prior to measurement and improper contacting. The data acquisition system can change the efficiency by sweeping the device voltage too fast; allowing the calibration to drift; neglecting the spectral mismatch error; or having spatial nonuniformities in the illumination. PV devices can be processed to give a high initial efficiency at the expense of stability. The so-called active area is the most common definition-related method of artificially improving the efficiency. Efficiency differences for thermophotovoltaic devices are dominated by differences in the reference conditions caused by a lack of standardization.