Outdoor organic photovoltaic module characteristics: Benchmarking against other PV technologies for performance, calculation of Ross coefficient and outdoor stability monitoring

Abstract

A comparison of performance parameters for first, second and third generation PV technologies has been conducted. Organic photovoltaic (OPV) modules displayed markedly different outdoor performance characteristics to other PV technologies owing to the positive temperature coefficient, lower thermal mass and response under low light conditions. The linear relationship between irradiance and module temperature rise above ambient is studied, leading to calculation of values for the Ross coefficient for OPV modules. OPVs are shown to possess a lower Ross coefficient than poly-Si, due to the lower absorption of infrared radiation. The effect of wind speed on the Ross coefficient is also investigated, showing the effect that module structure has upon outdoor PV performance, with the OPV module cooling quicker under windy conditions than the poly-Si due to a lower thermal mass. A long term stability study on OPV modules with a silver nanowire-zinc oxide (AgNW-ZnO) composite front electrode has showed two phases of degradation: a short initial burn-in with significant drops in performance; followed by stabilisation and degradation progressing at a much slower rate. During the burn-in period the modules showed diurnal reversible degradation in the short circuit current (ISC), whereas open circuit voltage (VOC) and fill factor (FF) show a steady decline. The reversible degradation is assumed to be related to the desorption of oxygen from the ZnO layer during the day due to UV excitation, leading to an increase in trap formation and a drop in current generation capacity, followed by re-adsorption of the oxygen overnight.

Outdoor performance monitoring of perovskite solar cell mini-modules: Diurnal performance, observance of reversible degradation and variation with climatic performance

“…At the higher irradiance level, the modules demonstrate a small drop in VOC, which is overwhelmed by increases in JSC and FF leading to a slight positive PCE coefficient (+0.0078 %/K). This is particularly interested as very few PV technologies possess a positive temperature coefficient in outdoor conditions (OPVs and DSCs are the exceptions) [9] which supports the indoor data supplied by Leong et al [28].…”

“…Visoly-Fisher et al showed OPV devices can rise in temperature with exposure to sunlight even with the IR part of the spectrum omitted [30]. The figures for Ross coefficient are slightly lower than those obtained in previous experiments by this group on organic photovoltaic (OPV) modules (0.027 K m 2 /W) and polycrystalline (poly-Si) modules (0.028 K m 2 /W) [9]. The difference is partly due to the location of the PT100 temperature sensor which was positioned behind the glass substrate that the modules were laminated onto, and partly due to the large substrate to active area ratio; both these factors leading to temperature loss and a reduction in the Ross coefficient.…”

“…Furthermore, small devices are difficult to measure outdoors with high accuracy, as the currents involved are small (nA), especially at lower irradiances, and require the use of specialist test equipment, which has impeded studies on outdoor testing [8], [9].…”

Simultaneous enhanced efficiency and thermal stability in organic solar cells from a polymer acceptor additive

“…Despite the great achievements in improving efficiency, commercialization of large-scale OSCs is limited due to their relatively low environmental stability 8,[12][13][14][15][16] . Of note is that many environmental issues (e.g., heat, oxygen, light, and humidity) have been identified as main factors of device degradation 17 . These parameters should be properly addressed to meet the requirements of practical outdoor application of OSCs.…”

Development of An Improved Computer Model for Organic Photovoltaic Cells

“…The simulation results are shown in Section III. The PV modules performance in terms of voltage, current and power have been monitored in an outdoor environment [11] and they will be compared with model obtained in MATLAB/Simulink in Section IV.…”