Compositional and Interfacial Engineering Yield High-Performance and Stable p-i-n Perovskite Solar Cells and Mini-Modules

Janardan Dagar,Antonio Abate,Markus Fenske,Rutger Schlatmann,Igal Levine,Hampus Näsström,Christof Schultz,Thomas Unold,Hans Köbler,Eva Unger,Jinzhao Li,Bert Stegemann,Steve Albrecht,Gopinath Parmasivam,Aboma Merdasa,Rahim Munir,Bor Li,Lukas Kegelmann,Daniel M Többens,Amran Al‐Ashouri ,J.a Marquez

doi:10.1021/acsami.0c17893

Abstract

Through the optimization of the perovskite precursor composition and interfaces to selective contacts, we achieved a p-i-n-type perovskite solar cell (PSC) with a 22.3% power conversion efficiency (PCE). This is a new performance record for a PSC with an absorber bandgap of 1.63 eV. We demonstrate that the high device performance originates from a synergy between (1) an improved perovskite absorber quality when introducing formamidinium chloride (FACl) as an additive in the "triple cation" Cs0.05FA0.79MA0.16PbBr0.51I2.49 (Cs-MAFA) perovskite precursor ink, (2) an increased open-circuit voltage, VOC, due to reduced recombination losses when using a lithium fluoride (LiF) interfacial buffer layer, and (3) high-quality hole-selective contacts with a self-assembled monolayer (SAM) of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz) on ITO electrodes. While all devices exhibit a high performance after fabrication, as determined from current-density voltage, J-V, measurements, substantial differences in device performance become apparent when considering longer-term stability data. A reduced long-term stability of devices with the introduction of a LiF interlayer is compensated for by using FACl as an additive in the metal-halide perovskite thin-film deposition. Optimized devices maintained about 80% of the initial average PCE during maximum power point (MPP) tracking for >700 h. We scaled the optimized device architecture to larger areas and achieved fully laser patterned series-interconnected mini-modules with a PCE of 19.4% for a 2.2 cm2 active area. A robust device architecture and reproducible deposition methods are fundamental for high performance and stable large-area single junction and tandem modules based on PSCs.

Highlights

Hybrid organic−inorganic lead halide perovskites solar cells (PSCs) have been demonstrated to yield impressive power conversion efficiencies above 25% for small area devices,[1] enthralling high aspiration for next-generation solar cell technology.[2−9] The scalability and stability of high-performingperovskite solar cell (PSC) are challenges for the commercial prospects of this technology
The p-i-n architecture becomes of increasing importance as a top cell in 2-terminal tandem solar cells based on silicon for the following reasons:[21−23] p-i-n devices can be manufactured with only low-temperature processing steps involved, which reduces the risk of potential performance losses in the silicon bottom
A cross-sectional scanning electron microscopy (SEM) image is shown in Figure 1a, and a schematic picture in Figure 1b illustrates the p-i-n perovskite solar cell devices (PSCs) with the layer stack glass/ ITO/self-assembled monolayer (SAM)/perovskite/lithium fluoride (LiF)/C60/SnO2/Cu investigated

Summary

INTRODUCTION

Hybrid organic−inorganic lead halide perovskites solar cells (PSCs) have been demonstrated to yield impressive power conversion efficiencies above 25% for small area devices,[1] enthralling high aspiration for next-generation solar cell technology.[2−9] The scalability and stability of high-performing. We here demonstrate the unique synergistic effect of utilizing both FACl as an additive in perovskite thin-film preparation and LiF as an interfacial layer in p-i-n perovskite devices on the basis of a self-assembled monolayer (SAM) hole-selective contacts of 2PACz ([2-(9H-carbazol-9-yl)ethyl]phosphonic acid).[23,40] These three strategies combined enabled us to demonstrate record efficiencies for p-i-n perovskite solar cell devices of up to 22.3% These results are the highest for SAM-based p-i-n perovskite solar cells, on par with the recently published record for p-i-n solar cells[9] and the highest performance of a perovskite solar cell with 1.63 eV in both polarities. We are highlighting the importance of evaluating device architectures on the basis of longer-term performance rather than the initial PCE derived from J−V measurements to enable identifying device architectures and components that are most viable to develop efficient perovskite device technology on larger areas

RESULTS AND DISCUSSION

CONCLUSION

■ ACKNOWLEDGMENTS

■ REFERENCES