Influence of aluminium electrode preparation on PCE values of polymeric solar cells based on P3HT and PCBM

Roll‐to‐Roll Sputter Coating of Aluminum Cathodes for Large‐Scale Fabrication of Organic Photovoltaic Devices

“…Them echanism for creation of this buried oxide layer remains unclear, although many previous reports have speculated that chemical reactions are likely at such interfaces due to the highly energetic particle collisions inherent in the sputtering process. [12,14,16] TheA l/C ratio,i ndicative of the penetrationo fa luminum atoms into the organic films,f ollows as imilar trend (with respect to sputtering target power)a st hat observed for the oxide formation (Figure 3b inset).T here is an initial increase in the penetrationd epth with increasing sputteringp ower, with ap enetration of approximately 3nmo bserved at 100 W, increasing to 6-8 nm at 500 W. However, further increases in the target power up to am aximumo f1 500 Wd id not create any further penetrationo ft he aluminum atoms into the organic film. This penetrationd epth is identical to that typically observed for evaporated aluminumc ontacts using similar XPS measurements, [29] which indicates that the sputtering depositiont echnique does not generate excess penetration of aluminumi nto the organicl ayer as compared to standard physical vapor depositiont echniques employed in high-efficiency small-scale devices.F urthermore,t he penetration depth of the aluminum determined by the Al/C ratio is consistent with the penetrationd epth of the oxide layer determined from the O/Al ratio,w hich suggests that the majority of the penetrating aluminumi sa ssociated with the interfacial oxide layer.…”

“…However, previous attemptst oc reate sputtered contacts in organic electronic devices,i ncluding OLEDsa nd OPVs,h ave observed significant performance limitations when depositingd irectly onto soft organic films. [12,13] Although the mechanism responsible for performance limitations remains unclear, the bombardment of the organic film with af lux of energeticg as ions and metal particles during sputtering has been postulated to deform devicest hrough direct damage of the photoactive layer [14][15][16][17] or through penetration of the metal atomst hrough the soft organic layer to create al ow shunt resistance. [18,19] Attempts to remedy damages caused by sputtering metal contacts onto organic films have shown some success.T he depositiono fb uffer layers on top of the organic films,t ypically containing lithium ions, [8,20] and the application of intricate post-deposition thermal annealing treatments [21][22][23][24] have both been demonstrated as successful pathways to recover the performance of poorly functioning OLED and OPV devices prepared using sputtered contacts.However, adefinitive mechanism for these procedures,a nd the underlying origin of poor performancei nd evices prepared with sputtered contacts,r emains unclear.…”

Modern Nanocomposites and Hybrids as Electrode Materials Used in Energy Carriers

“…In turn, the fourth generation cells are mostly organic groups, including polymers, chemically modified oxide graphene, nanotubes, TiO x or ZnO [ 206 , 207 ]. Work on the development of polymer photovoltaics, which was carried out in Wrocław (Poland), aimed at the construction and characteristics of photovoltaic cellular polymer cells, both on the substrate rigid as well as flexible, containing polymer rye of various chemical structure, fullerene derivatives (PCBM—[6,6]-phenyl-C 61 -butyric acid methyl ester, PC 71 BM—[6,6]-phenyl-C 71 -butyric acid methyl ester), as well as graphene oxide, nanotubes, TiO 2 , Ag, and liquid crystals [ 208 , 209 , 210 , 211 , 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 , 220 , 221 ]. Details of the mechanism of action and type of organic photovoltaic cells is discussed in the publication [ 206 , 222 ].…”

Initial photooxidation mechanism leading to reactive radical formation of polythiophene derivatives

“…Poly(3-hexylthiophene) (P3HT) is one of the most widely employed p-type materials for the photoactive layer of PSCs. [1][2][3][4] Furthermore, it is also known that the use of P3HT degrades PSCs on long-term irradiation of solar light. [5][6][7][8][9][10][11] Jørgensen et al 11,12 recently proposed that the degradation mechanism of PSCs was related to the photooxidation of P3HT.…”

“…The polymer cation and the counter anion would also have an influence on the photooxidation reaction. 1 To understand the role of other active species in the photooxidation of polythiophene derivatives and the mechanism of radical formation by such species, P3HT and photostable P3OOT thin films were irradiated by light. Differences in the photochemical behavior between P3HT and P3OOT were observed by light-induced ESR, ultravioletvisible-near-infrared spectroscopy and density functional theory (DFT) calculations.…”