A quantitative study of the formation of PCBM clusters upon thermal annealing of P3HT/PCBM bulk heterojunction solar cell

Effects of PCBM Loading and Thermal Annealing on Nanomorphology of Blend of Polymer/Fullerene Thin Films Solar Cells: Impact on Charge Carrier Mobility and Efficiency

“…This correlates well with the lowest recombination rates recorded at this temperature. It should be pointed out that the maximum exciton generation rate has also been deduced at this temperature as we have previously reported [16]. However for 1:0.6 devices, no correlation between the recombination rate and the short circuit current density is observed.…”

“…Whilst the peak optical absorption intensity of the PCBM has little to do with the current density, its cluster formation i.e. size, distribution, orientations, etc., may or may not result in more efficient exciton dissociation [16]. relationship may be written as [17] e(h e(h (1) where q is the electron charge, is electron (hole) carrier mobility, is the electron (hole) concentration, and d is the device active layer thickness.…”

Effect of preparation parameters on performance of P3HT: PCBM solar cells

“…The result is probably ascribed to the increase in exciton dissociation. Thermal annealing at higher temperature would lead to rough surface of the active layer, which in turn reduces the free volume and improves the interface with the electrode [19,27]. Size of PCBM domains increased as the phase separation was developed during the annealing treatment.…”

Towards High Performance Organic Photovoltaic Cells: A Review of Recent Development in Organic Photovoltaics

“…In last two years, several novel monitor methods have been introduced in order to further illuminate the mechanism of thermal annealing on the performance of the standard OPV based on P3HT:PCBM BHJ. Oklobia et al investigated the formation of PCBM clusters upon thermal annealing of a P3HT/PCBM BHJ solar cell by using Raman image mapping, which is able to identify the PCBM rich region, as shown in Figure 14 [117]. The diffusion of PCBM molecules to form aggregates was scrupulously manipulated to induce a nano-structure to benefit the device performance by gradually annealing the blend film, from low temperatures through to an optimum temperature.…”