The impact of annealing process on the grain morphology and performance of mesoporous n-i-p carbon-based perovskite solar cells

Abstract

Organic–inorganic perovskite solar cells (PSCs) have been emerging as one of the most promising photovoltaic technologies. Surface morphology is considered as a key-parameter in energy alignment and plays a dominant role in specifying the device performance. The large grains and low roughness enhance the transport of charge carriers from perovskite layers to the transport layers, and this reflects on the delivered power conversion efficiency (PCE). Therefore, in this study, we investigated the influence of the fabrication parameters on the grain size and the morphology of perovskite layers, thereby the PCE of PSCs. These parameters included the anti-solvent nature (chlorobenzene or toluene), annealing temperature, and annealing ramp rate (slow or flash annealing). The scanning electron microscope confirmed that flash annealing results in a better morphology than slow annealing whether by employing an anti-solvent dripping or not. Furthermore, the dripping of chlorobenzene as an anti-solvent produced better morphology and large grains compared with toluene. Therefore, combining chlorobenzene with flash annealing induced the formation of large grains, full cover, and a uniform perovskite layer, which reflects on the performance of the fabricated PSCs. Finally, employing the aforementioned optimum preparation parameters to fabricate carbon-based PSCs resulted in decent PCE, current density short circuit (Jsc), open circuit voltage (Voc), and fill factor (FF) of 7%, 11.3 mA/cm2, 0.74 V, and 34%, respectively.

Structural and Optical Properties of Vacuum‐Evaporated Mixed‐Halide Perovskite Layers on Nanotextured Black Silicon

“…It is known that perovskite layers with large grains have better optoelectronic properties owing to the efficiency of charge carrier collection and the reduction of charge recombination at grain boundaries. [48,49] Therefore, a perovskite layer with larger grains is considered a higher-quality photoabsorbent material.…”

Perovskite grain wrapping by converting interfaces and grain boundaries into robust and water-insoluble low-dimensional perovskites

“…Many different strategies have been applied to improve the intrinsic stability of the perovskite layers, including compositional engineering, morphology improvement, defect passi vation, charge transport layer modifications, strain engineering, etc. (1)(2)(3)(4)(5)(6). Incorporating metal cations such as Cs + was found to en hance the thermal stability and, more importantly, the light stability of methylammonium lead iodide perovskite (MAPbI 3 ) (7).…”