Deterministic fabrication of 3D/2D perovskite bilayer stacks for durable and efficient solar cells

• Published in: Science (American Association for the Advancement of Science) Vol. 377; no. 6613; pp. 1425 - 1430
• Main Authors: Sidhik, Siraj, Wang, Yafei, De Siena, Michael, Asadpour, Reza, Torma, Andrew J., Terlier, Tanguy, Ho, Kevin, Li, Wenbin, Puthirath, Anand B., Shuai, Xinting, Agrawal, Ayush, Traore, Boubacar, Jones, Matthew, Giridharagopal, Rajiv, Ajayan, Pulickel M., Strzalka, Joseph, Ginger, David S., Katan, Claudine, Alam, Muhammad Ashraful, Even, Jacky, Kanatzidis, Mercouri G., Mohite, Aditya D.
• Format: Journal Article
• Language: English
• Published: Washington The American Association for the Advancement of Science 23.09.2022; American Association for the Advancement of Science (AAAS); AAAS
• Subjects: Chemical Sciences; Dielectric constant; Dielectric strength; Energy conversion efficiency; Fabrication; or physical chemistry; Perovskites; Photodegradation; Photovoltaic cells; Relative humidity; Solar cells; SOLAR ENERGY; Spin coating; Substrates; Theoretical and
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.abq7652

Realizing solution-processed heterostructures is a long-enduring challenge in halide perovskites because of solvent incompatibilities that disrupt the underlying layer. By leveraging the solvent dielectric constant and Gutmann donor number, we could grow phase-pure two-dimensional (2D) halide perovskite stacks of the desired composition, thickness, and bandgap onto 3D perovskites without dissolving the underlying substrate. Characterization reveals a 3D–2D transition region of 20 nanometers mainly determined by the roughness of the bottom 3D layer. Thickness dependence of the 2D perovskite layer reveals the anticipated trends for n-i-p and p-i-n architectures, which is consistent with band alignment and carrier transport limits for 2D perovskites. We measured a photovoltaic efficiency of 24.5%, with exceptional stability of T 99 (time required to preserve 99% of initial photovoltaic efficiency) of >2000 hours, implying that the 3D/2D bilayer inherits the intrinsic durability of 2D perovskite without compromising efficiency. Two-dimensional (2D) halide perovskite passivation layers grown on three-dimensional (3D) perovskite can boost the power conversion efficiency (PCE) of solar cells, but spin-coating of these layers usually forms heterogeneous 2D phases or only ultrathin layers. Sidhik et al . found that solvents with the appropriate dielectric constant and donor strength could grow phase-pure 2D phases of controlled thickness and composition on 3D substrates without dissolving them. Solar cells maintained a peak PCE of 24.5% for 2000 hours with less than 1% degradation under continuous light at 55°C and 65% relative humidity. —PDS Solvents enable growth of phase-pure two-dimensional perovskites without dissolving three-dimensional perovskite substrates.