Molecular Contacts

Molecular contacts have driven a paradigm shift in high-efficiency perovskite solar cells by enabling precise control over charge extraction and significantly reducing interfacial losses. Through tailored energy-level alignment and defect passivation, they have contributed decisively to record power conversion efficiencies. Despite this progress, fundamental questions remain regarding their effective surface coverage on oxide electrodes, interfacial uniformity, and long-term operational stability—issues that currently limit reliable device integration and scalability.

Our research addresses these challenges by developing chemically and electronically well-defined molecular interfaces that combine molecular design principles with semiconductor device physics. We aim to establish molecular contacts that are not only performance-enhancing but also robust, reproducible, and compatible with scalable manufacturing.

Molecular contacts as a unifying interfacial design paradigm

Overcoming the intrinsic interfacial limitations of perovskite optoelectronics requires a shift from conventional bulk transport layers toward molecularly engineered contacts that integrate precise chemical control with targeted electronic functionality. These contacts, based on organic molecules or organic–inorganic hybrid materials, enable covalently anchored, ultra-thin, and chemically stable interfaces with tunable optoelectronic properties.

In our work, molecular contacts serve as a unifying interfacial design paradigm, bridging molecular chemistry, materials science, and device engineering. We categorize them into three distinct yet complementary classes:

• Self-Assembled Monolayers (SAMs):
  Chemically robust, molecularly thin layers used for precise energy-level alignment and work-function tuning on transparent conductive oxides (TCOs), enabling efficient and selective charge extraction.

• Low-Dimensional Perovskites (LDPs):
  Organic–inorganic hybrid interlayers that act as structural templates, passivation layers, or energetic barriers, enhancing interfacial stability while controlling charge blocking and extraction.

• Small Molecules:
  Tailored organic or hybrid molecules incorporated at critical interfaces to suppress non-radiative recombination and mitigate interfacial defect states.

Our long-term vision is to establish molecular contacts as a foundational interfacial strategy for perovskite optoelectronics, applicable across single-junction, tandem, and module-level devices. Achieving this requires researchers trained to operate across disciplinary boundaries.