Representative identification of spectra and environments (RISE) using k‐means

Abstract

Spectral differences affect solar cell performance, an effect that is especially visible when comparing different solar cell technologies. To reproduce the impact of varying spectra on solar cell performance in the lab, a unique classification of spectra is needed, which is currently missing in literature. The most commonly used classification, average photon energy (APE), is not unique, and a single APE value may represent various spectra depending on location. In this work, we propose a classification method based on an iterative use of the k-means clustering algorithm. We call this method RISE (Representative Identification of Spectra and the Environment). We define a set of 18 spectra using RISE and reproduce the spectral impact on energy yield for various solar cell technologies and locations. We explore effects on yield for commercially available solar cell technologies (Si and CdTe) in four locations: Singapore (fully humid equatorial climate), Colorado (cold arid), Brazil (warm, humid, and subtropical), and Denmark (fully humid warm temperature). We then reduce our findings to practice by implementing the spectrum set into an LED current-voltage (IV) tester. We verify our performance predictions using our set of representative spectra to reproduce energy yield differences between Si solar cells and CdTe solar cells with an average error of less than 1.5 ± 0.5% as compared to over 5% when using standard testing conditions.

Intrinsic Organic Semiconductors as Hole Transport Layers in p–i–n Perovskite Solar Cells

“…When a device with the same architecture is measured with continuous maximum power point (MPP) tracking under simulated solar illumination, the same dynamic behavior is observed, and the PCE slowly rises in the first 15 min before stabilizing at the maximum value (Figure S3, Supporting Information). The same electrical behavior was observed by using a light‐emitting diode (LED) solar simulator with UV component, [ 51 ] as well as with a halogen lamp, with virtually no UV component. No differences were observed, suggesting that the light spectrum is not playing an important role in the device activation.…”

Performance assessment of bare and anti‐reflective coated CdTe photovoltaic systems in comparison to multicrystalline Si in Brazil

“…The higher band gap value of CdTe when compared to silicon (1.5 eV for CdTe vs. 1.1 eV for Si) results in a blue-shifted spectral response, as shown in Figure 11. This shift in spectral responsivity results in spectral gains for CdTe PV systems in Brazil, as previously reported in the literature by Braga et al, 14,15 Polo et al, 53 and Looney et al 54 In this study, a spectral evaluation was carried out in order to quantify seasonal spectral gains and losses for the evaluated PV…”

Influence of the Bulk Resistivity on Silicon Heterojunction Solar Cells and Module Reliability

“…For instance, the illumination conditions experienced by a module vary according with the time of the day, geographical location, cloudy sky conditions, and others. [ 6,23–25 ] The illumination intensity experienced by modules during the day greatly affects the output power, and the response to different illuminations can differ greatly between different bulk qualities and cell concepts. [ 1,6 ] Under STC conditions, the effective bulk resistivity of a solar cell with excellent surface passivation and high bulk lifetime is driven less by the bulk doping than by the excess carrier concentration.…”