The performance of low-cost, solution processed perovskite solar cells has greatly advanced in recent years, but these advancements are mostly limited to small area devices utilizing non-scalable fabrication methods. Our research includes efforts to increase the scalability of perovskite fabrication while adapting our device architecture to accommodate large area material depositions through the use of laser-scribed series interconnections.
In order to realize high performing large-area perovskite modules, scalable fabrication methods must be employed to be compatible with our large-area laser-scribed design. An innovative plasma curing method, RSPP, allows for high throughput, efficient, and mechanically robust perovskite films with deposition rates of > 10 cm/s in open air, the highest throughput for any perovskite deposition method. This process paves the way for module fabrication on larger substrates, allowing for greater development of new laser-scribed architectures and larger modules.
Fig. 1: Photograph of a perovskite film deposited by RSPP on 930 cm2 glass in under 4 min.
One of the principle concerns in the development of large-area perovskite devices is an increase in resistive losses throughout the device, most notably due to the non-negligible sheet resistance of the transparent front electrode combined with an increase in current output over a larger area. Therefore, achieving large-area devices requires developing a new architecture based on monolithically series interconnected subcells with low-cost laser-scribed interconnections.
Laser Scribe Interconnection Optimization
Using a single source pulsed laser at speeds > 20 cm/s, submillimeter width “dead areas” are achieved on large-area substrates with successful series interconnections involving a P1, P2, and P3 laser scribe. The P1 and P3 scribes serve to isolate the front and rear electrodes, respectively, while the P2 is responsible for providing the series interconnection between adjacent cells. All three scribe processes utilize a single wavelength laser source with a unique scribing method that outperforms conventional direct ablation mechanisms. This method allows for rapid, repeatable, and narrow laser scribes requiring only a single laser source, enabling reduced costs and high throughput module production.
Fig. 2: Laser-scribed module schematic highlighting the series interconnection of adjacent cells.
Module Architecture Optimization for Improved Performance and Characterization
Accommodating large-area perovskite films with laser-scribed series interconnections requires an optimized module architecture and geometry in order to mitigate resistive losses and maintain large active device areas. We’ve demonstrated single-source laser-scribed large area perovskite modules on films ranging from 0.5 cm2 to > 20cm2 while maintaining module performance with an optimized cell geometry and module design. Additional module optimization and characterization is also enabled with an Adaptive Architecture, providing improved insight into the individual cell and module performance across an entire device.