P3HT:PCBM polymer solar cells from a didactic perspective

Abstract

Here, we studied the influence of pre-and post-thermal annealing on the performance of polymer:fullerene bulk heterojunction solar cells using the conventional architecture, comprising a conjugated polymer, namely, poly(3-hexylthiophene-2,5-diyl) (P3HT) and a fullerene derivative [6,6]-phenyl-C60-butyric acid methyl ester (PC 60 BM) as a photoactive layer. The nonannealed active layer device exhibited a power conversion efficiency of <1%, which was significantly lower than the pre-and post-annealed devices. To investigate the impact of pre-and post thermal annealing on the natural morphological state of the polymer, regiorandom (P3HT-I) and regioregular (P3HT-II) type P3HT were compared in photoactive layers. In general, P3HT-I is amorphous, whereas P3HT-II is semi-crystalline. Changes in solar cell performance were associated with changes in carrier extraction efficiencies influenced by the annealing conditions. The charge photogeneration processes were investigated using spectroscopic techniques, including electroluminescence, steady-state, and time-resolved photoluminescence spectroscopy. Finally, to explore the morphological changes upon annealing, atomic force microscopy and electroluminescence imaging measurements were performed on films and solar cells, respectively. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Thermally‐Induced Degradation in PM6:Y6‐Based Bulk Heterojunction Organic Solar Cells

“…The exciton dissociation efficiency ( η diss = J SC / J sat ) and charge collection efficiency ( η coll = J MPP / J sat ) were calculated at short circuit conditions and at the maximum power point, respectively. [ 57 ]…”

“…The exciton dissociation efficiency (𝜂 diss = J SC /J sat ) and charge collection efficiency (𝜂 coll = J MPP /J sat ) were calculated at short circuit conditions and at the maximum power point, respectively. [57] TPC measurements were performed to understand qualitative differences of the charge carrier transport properties, and the photocurrent decay was monitored after excitation with a 100 μs pulse, as shown in Figure 5a. The ratio between charge carriers extracted swiftly and those extracted after some delay time became smaller for increasing annealing temperatures.…”

Influence of thermal annealing on microstructure, energetic landscape and device performance of P3HT:PCBM-based organic solar cells

“…In previous work, we presented a study on P3HT:PCBM-based organic solar cells, using several optoelectronic and spectroscopic measurements to investigate their photovoltaic properties. Photoluminescence (PL) studies demonstrated the highest film crystallinity for annealed films, which was confirmed by atomic force microscopy (AFM) [51]. An enhancement in crystallinity was primarily responsible for the improved photovoltaic characteristics upon annealing.…”

Electronic and Photochemical Passivation by a Classic Sunscreen Material Leading to Reduced Voc Losses and Enhanced Stability in Organic Solar Cells

“…The device containing BP-3 can still significantly improve the UV stability in the harsh conditions of ISOS-L2. Electroluminescence imaging (ELI) was employed during the ISOS-L2 process to evaluate defect density for all layer stacks and the ability of charge carrier injection from the top electrode with the same set current of 20 mA, , and the original data are all shown in Figure S20. In contrast to a ZnO/BP-3-based device, a ZnO-based device with no modification layer of BP-3 exhibits a larger defect density and a similar brightness, indicating that the modification layer of BP-3 does not affect charge injection negatively while reducing the device’s internal defect density.…”