Abstract
In recent years, hybrid organic-inorganic halide perovskites have been widely studied for the low-cost fabrication of a wide range of optoelectronic devices, including impressive perovskite-based solar cells. Amongst the key factors influencing the performance of these devices, recent efforts have focused on tailoring the granularity and microstructure of the perovskite films. Albeit, a cost-effective technique allowing to carefully control their microstructure in ambient environmental conditions has not been realized. We report on a solvent-antisolvent ambient processed CH3NH3PbI3−xClx based thin films using a simple and robust solvent engineering technique to achieve large grains (>5 µm) having excellent crystalline quality and surface coverage with very low pinhole density. Using optimized treatment (75% chlorobenzene and 25% ethanol), we achieve highly-compact perovskite films with 99.97% surface coverage to produce solar cells with power conversion efficiencies (PCEs) up-to 14.0%. In these planar solar cells, we find that the density and size of the pinholes are the dominant factors that affect their overall performances. This work provides a promising solvent treatment technique in ambient conditions and paves the way for further optimization of large area thin films and high performance perovskite solar cells.
Highlights
9,9′-spirobifluorene (Spiro-MeOTAD) poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT:PSS) as hole extractors have been implemented using various deposition techniques[9,15,20,22,23]
We address the key challenge of controlling the microstructure of the perovskite films processed in ambient conditions by using a cost-effective solvent treatment approach to synthesize highly-oriented crystallites with statistically-controlled grain sizes and low pinhole densities
We demonstrate the effect of pinhole densities and sizes on the shunt resistance[36], which in-turn affects the fill factor (FF) and the power conversion efficiencies (PCEs) of the devices
Summary
9,9′-spirobifluorene (Spiro-MeOTAD) poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT:PSS) as hole extractors have been implemented using various deposition techniques[9,15,20,22,23]. We address the key challenge of controlling the microstructure of the perovskite films processed in ambient conditions by using a cost-effective solvent treatment approach to synthesize highly-oriented crystallites with statistically-controlled grain sizes and low pinhole densities. This approach yields high quality films with 5 μm grains and minimized grain boundaries. Using an optimized solvent treatment promoting films with larger grains and lower pinhole densities, PCEs up-to 14% are achieved for planar solar cells processed in ambient conditions This novel solvent engineering approach yields significantly-improved crystal grain sizes and low pinhole densities, yet leaving room for further optimization. For simple planar PSC architectures, this work represents an important step towards the realization of high-quality perovskite film for low-cost and high-performance PSC devices
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
