Polymer:fullerene nanoparticles (NPs) offer two key advantages over bulk heterojunction (BHJ) films for organic photovoltaics (OPVs), water-processability and potentially superior morphological control. Once an optimal active layer morphology is reached, maintaining this morphology at OPV operating temperatures is key to the lifetime of a device. Here we study the morphology of the PDPP-TNT (poly{3,6-dithiophene-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-naphthalene}):PC71BM ([6,6]-phenyl C71 butyric acid methyl ester) NP system and then compare the thermal stability of NP and BHJ films to the common poly(3-hexylthiophene) (P3HT): phenyl C61 butyric acid methyl ester (PC61BM) system. We find that material Tg plays a key role in the superior thermal stability of the PDPP-TNT:PC71BM system; whereas for the P3HT:PC61BM system, domain structure is critical.

Proton implantation and thermal annealing of silicon result in the formation of a specific type of extended defect involving hydrogen, named “platelets”. These defects have been related to the exfoliation mechanism on which a newly developed process to transfer thin films of silicon onto various substrates is based. In a previous paper, we have shown that these platelets undergo a quasi-conservative Ostwald ripening upon annealing. The measurement of the pressure within such pressurised gas-filled cavities is important to understand and simulate both the growth of these defects and the exfoliation mechanism. To extract this pressure from TEM studies, we have developed and tested an analogy between the platelets and a well-known 2D defect: a dislocation loop. The comparison between simulations of the image of the strain field surrounding a fictitious dislocation loop and experimental TEM images of the platelets shows that the platelets can be described by a Burgers vector of about 0.6nm. Moreover, this vector can be used to deduce the pressure of the molecular hydrogen within a platelet. A typical value of 10 GPa is found for a platelet of 20 nm in diameter at room temperature. Consequently, the atomic density of hydrogen within a platelet and the total number of hydrogen trapped by a population of platelet can be calculated and give reasonable values when compared to the implanted dose.