What is killing organic photovoltaics: light-induced crosslinking as a general degradation pathway of organic conjugated molecules

Balancing the efficiency, stability, and cost potential for organic solar cells via a new figure of merit

“…11 Although there is still room to make small improvements in efficiency, challenging the current state-of-the-art PCEs reported for various donor/acceptor (D/A) combinations, 2,7,12,13 it is urgently needed to pay more endeavors on the other two crucial issues (stability and cost) that must be resolved for the commercial application of OSCs. 1,11,14,15 On the basis of the great efforts of researchers on addressing to meet the requirements for the practical outdoor application of OSCs, 11,[16][17][18][19] one can find that there are many limiting factors, including external stresses and intrinsic instabilities, 20,21 which can happen simultaneously. On the one hand, OSCs inevitably suffer from external stresses under operational conditions, including irradiation, heating, oxidation, and humidity.…”

The role of spin in the degradation of organic photovoltaics

“…More worryingly, since back electron and HT are not specific to fullerenes, our finding that triplets produced by BHT can cause rapid photo-degradation even under inert conditions has a wider relevance for OPV and should be carefully studied in NFAs. The recent suggestion that triplet-mediated [2 + 2] cycloadditions, of which fullerene dimerization is an example, occur in a wide range of neat organic semi-conductor films upon light exposure reinforces this message 36 . Nevertheless, the significantly improved early-time stability of several NFAs when compared to PC 61 BM suggests it is possible to find acceptors, which are intrinsically stable to triplet-mediated reactions under inert conditions [80][81][82][83] .…”

“…A degradation process resulting from BHT cannot be avoided by simply tuning the morphology or improving exciton quenching, making dimerization a much more serious concern than previously thought. As this triplet formation pathway is not specific to fullerenes and [2 + 2] cycloadditions are thought to occur in a wide range of materials 36 , BHT or BET could well mediate other intrinsic degradation processes in a variety of systems, including those using high-performance NFAs.…”

High-performance, low-voltage organic field-effect transistors using thieno[3,2-b]thiophene and benzothiadiazole co-polymers

“…Organic semiconducting materials have gained significant attention due to their advantages of easy processability, high mechanical flexibility, high electroactivity and chemical structure tunability in comparison with inorganic semiconductors. 13 These advantages make them promising materials in organic light emitting diodes (OLEDs), [14][15][16][17] organic solar cells, [18][19][20] organic photovoltaics (OPVs) [21][22][23] and organic field-effect transistors (OFETs). [24][25][26][27][28][29][30] OFETs form the basic building blocks of many organic and hybrid electronic devices such as flexible radio-frequency identification tags, large-area sensors and flexible displays, and smart cards and sensors, thus providing an excellent platform for fundamental studies of charge transport in organic semiconductors (OSCs).…”