Semiconductors are an indispensable part of modern-day technologies ranging from computers and smartphones to solar panels and LED lighting. Their ability to control the flow of electrical charge makes them essential for how devices generate, process, and use energy. In renewable energy technologies such as solar cells, semiconductor performance directly determines how efficiently sunlight can be converted into electricity. Conventional semiconductor materials are mostly silicon-based, while new age semiconductors (such as perovskite-based and organic semiconductors) address the challenges associated with conventional silicon-based semiconductors.
Perovskite-based and organic-based semiconductors are widely used in emerging technologies such as flexible electronics, light-emitting devices, and high-efficiency solar cells. Thus, unlocking the potential of these semiconductor materials is therefore critical for developing sustainable energy technologies and reducing the energy dependence on fossil fuels.
Scientists use a method called 'electronic doping' to control the charge transport properties of the semiconductor material. Conventional doping methods often depend on the addition of metal salts, other organic additives, and slow processing steps that leave behind chemical residues and compromise long-term device stability. Moreover, such conventional doping methods depend heavily on 'trial-and-error' approaches, and hence, have lesser predictability in terms of outcome. To address this gap, researchers led by Dr. Pabitra Nayak at the Tata Institute of Fundamental Research, Hyderabad, have now introduced a new doping strategy called in situ regenerative adduct-assisted (IRAA) doping, a breakthrough approach that could redefine how organic semiconductors are electronically doped for next-generation optoelectronic devices.
At the center of the advance is IRAA, a rapid, additive-free doping strategy that generates a self-regenerating active doping species directly during the process. Unlike traditional approaches, IRAA eliminates the need for stabilizing additives or prolonged incubation, enabling cleaner, faster, and more efficient doping of organic semiconductors.
The work does not merely improve existing semiconductor doping approaches; it redefines the principles of electronic doping in soft semiconductors, transforming the field from an empirical and constrained practice into a predictive, modular, and design-driven framework. The research marks a decisive shift away from trial-and-error optimization toward a regime in which electronic properties can be engineered with precision and flexibility.
Historically, electronic doping in organic semiconductors has been restricted by the limited availability of dopants, each carrying fixed compromises between efficiency, stability, and device compatibility. Further, electronic doping of organic semiconductors that have been in use for decades generally involve the use of a single dopant, with low efficiency.
A major impact of the IRAA strategy is the removal of this long-standing bottleneck in materials innovation. IRAA is an multi-component dopant system in which individual molecular components can be independently optimized for specific functions. As a result, doping becomes a tunable and adaptable process that can be tailored to different semiconductors, device architectures, and operating conditions, greatly expanding the accessible chemical and functional design space.
The simplicity, scalability, and universality of IRAA experimental protocol make it highly attractive for advanced optoelectronic manufacturing. The strategy is particularly promising for halide perovskite solar cells, where stable and efficient charge transport is essential for achieving high power conversion efficiencies and long operational lifetimes. Interestingly, the most conventionally used single junction solar cell in the world happens to be silicon-based ones, which can successfully convert 27.9% of incident sunlight to usable energy. Initially, (around a decade ago) when halide-perovskite cells came into the picture, the efficiency was ~10%. Since then, scientists have been trying to improve the efficiency as well as the stability of such solar cells. This halide perovskite cell constituted with the IRAA experimental protocol reports an efficiency of 24.6%, with scope for further improvement.
By introducing a clean, regenerative, and design-driven doping paradigm, IRAA opens a new frontier in semiconductor engineering and could accelerate the development of more durable, efficient, and commercially viable technologies for renewable energy and electronics.
Link to publication: In Situ Regenerative Adduct Assisted p-Type Doping of Organic Semiconductor
(Content: Pabitra K Nayak)
