PEDOT-graphene counter-electrode for solar and improved artificial light conversion in regular, bifacial and FTO-less cobalt mediated DSSCs

Conventional and Back-Illuminated Cobalt- and Iodine-Mediated Dye-Sensitized Solar Cells for Artificial and Solar Light Conversion

“…Even for back illumination, the optimized Co–20 device displayed a power density of 75.0 μW·cm –2 at 1000 lx (88.1 μW·cm –2 for the front illumination), rivaling the best results for cobalt- and copper-mediated DSSCs. ,− The results are attractive for constructing bifacial devices, i.e. , operating in conditions where both sides are illuminated simultaneously.…”

“…One of the critical observations in this study is that the device with the highest photocurrent under 1 Sun (I 2 –20) yields almost the same photocurrent as other devices (I 2 –50 and Co–20) under artificial light. This is related to the lower recombination under low irradiance, while under high irradiance, back-electron recombination becomes one of the PCE limiting factors . At weak illumination conditions, the ability of the device to generate high photovoltage becomes decisive for overall device performance, as observed by the PCE under 1 Sun and 1000 lx of back illumination for I 2 –20 and I 2 –50 devices.…”

“…Our previous studies revealed that I − /I 3 − DSSCs benefit from using ML30 and SL pastes (Figure 1e), while [Co(bpy) 3 ] 3+/2+ cells work best with the pastes ML20 and RL (Figure 1f). 20,38 When other conditions are the same (oxide layer thickness, photoanode architecture), cobalt cells with TiO 2 layers composed of 20 nm particles underperform counterparts with a mesoporous coating of 30 nm titania; the opposite is true for iodide devices (see Figure S2). The exact reason for this could be addressed in future studies.…”

“…Several studies have shown good performances of DSSCs under artificial light, utilizing iodide/triiodide − and cobalt redox mediators − and copper-based systems, ,,,, displaying PCEs of 28.7, 29.7%, and champion 34.5% under artificial illumination, respectively.…”

“…It could seem logical to assume that the best performing devices under standard AM1.5G illumination would be the best under other illuminating conditions. However, this is not the case . Usually, the limiting factor of the PCE is the charge recombination at the photoanode that occurs at higher power illumination, which strongly increases with the irradiance .…”