The Geometric Effect of SnOx Nanoparticle Interlayer on P3HT:PCBM Organic Solar Cell

In this study, we explore the coverage influence of SnOx nanoparticle (NP) interlayer on the indium tin oxide (ITO) electrode within standard-configured organic photovoltaic devices (OPVs) based on the poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methylester (PCBM) blend. By modifying the spacing of the NP layer using different spin-coating speeds, we observed an increase in short-circuit current density in NPs-incorporated devices. This enhancement is likely due to a reduced leakage current, as indicated by the performance metrics from the reverse-bias region under dark conditions, coupled with a higher carrier density traversing the transfer layers, which we associate with an increased likelihood of charge recombination. For the effect of NP spacing, we observed an optimal device performance when NPs were spaced approximately 80nm apart. Increasing the spacing beyond this point detrimentally impacted the parasitic resistance, leading to a decrease in fill factor and consequently, a limit on the efficiency enhancement. This performance degradation could be attributed to an imbalance in charge density across the device, as confirmed with SCAPS modelling. These findings suggest that precise control of NP distribution is essential for optimizing the injection properties in photovoltaic devices. By strategically managing SnOx NP spacing to around 80nm, it is possible to maximize the effect of the interlayer. This leads to an increase in device efficiency in OPVs by balancing enhanced charge transport and minimal parasitic resistance, thus paving the way for more efficient solar energy systems. Figure 1