Interlaboratory comparison of voltage sweep methods used for the electrical characterization of encapsulated high‐efficiency c‐Si solar cells

Abstract

This work presents the comparison of measurement results for four types of encapsulated high-efficiency c-Si solar cells measured by 10 laboratories based in Asia, Europe and North America utilizing a wide range of voltage sweeping methods, which include well-established procedures that represent good industry practice, as well as recently introduced ones that have not been verified yet. The aim of the round-robin interlaboratory comparison was to examine the measurement comparability of different laboratories with respect to their measurement methods of highefficiency solar cells. A proficiency test was employed to examine the consistency of results and their corresponding uncertainties. The short-circuit current (I SC ) under STC measured by four accredited laboratories was firstly compared. In order to investigate the consistency related to the high device capacitance, the value of the I SC was fixed for all 10 participants. The results of all participant laboratories-compared via E n number analysis-generally remained well within [À1; 1], thus indicating consistency between the measured values and the reference values within stated measurement uncertainties. The differences remained within ±1.15% in P MAX and within ±0.35% in V OC for all participants and methods applied. Correlations were observed among the P MAX , V OC , and FF differences from their weighted mean. An analysis of the effects of transient current (dQ/dt) at maximum power point caused by hysteresis effect on the measurement error of P MAX showed a significant linear correlation between error of maximum power and junction voltage sweep rate for heterojunction (HJT) solar cells. This work forms the basis to validate all applied methods and their stated measurement uncertainties.