This paper focuses on four parameter single-diode model applied to a heterojunction with intrinsic thin layer module. Matlab software was used to carry out the simulations of current-voltage (I-V) characteristic curves under varying irradiance and temperature conditions. Accuracy of the model was verified by outdoor measurements at different irradiance and temperature values. Series resistance as well as diode ideality factor were extracted from the modeling results. Relative errors were calculated for three main points of I-V characteristic curve: open circuit voltage, short circuit current and maximum power point. Root mean square errors of I-V curves were also computed. Analysis shows high accuracy of the model at considered conditions in case of open circuit voltage with up to 0.27% of maximum relative error and short circuit current with about 0.5% of relative error. Good agreement between simulated and measured values of maximum power points was also noticed at irradiance levels from 600 W/m(2) to 1000 W/m(2) (about 1% of relative errors). Calculated RMSE value of about 0.6% at high irradiances confirms high level of accuracy of presented model in application to a heterojunction with intrinsic thin layer module. (C) 2019 Elsevier Ltd. All rights reserved.