Conjugated N‐Type Diradical Semiconductor Empowers High‐Performance TiO2‐Based Perovskite Solar Cells

Why It Matters

By overcoming TiO₂’s defect‑induced losses, IDT‑R unlocks higher efficiencies and durability, accelerating the commercial viability of perovskite photovoltaics.

Key Takeaways

• IDT‑R reduces TiO₂ surface defects
• IDT‑R boosts TiO₂ electron mobility
• PSCs achieve 25.38% efficiency with IDT‑R
• Thermal stability improves in IDT‑R modified devices
• First n‑type diradical used for electron transport layer

Pulse Analysis

Titanium dioxide has long been the workhorse electron transport layer in perovskite solar cells, prized for its chemical stability and ease of processing. Yet its high density of surface traps and modest conductivity have limited device efficiencies, especially when compared with tin dioxide alternatives. Researchers have therefore pursued interface‑engineered solutions that can both passivate defects and enhance charge transport without compromising the material’s inherent advantages.

Enter IDT‑R, a novel n‑type conjugated diradical semiconductor engineered with energy levels aligned to TiO₂ and perovskite absorbers. Its diradical architecture provides delocalized unpaired electrons that readily fill TiO₂ surface states, effectively neutralizing trap sites. Simultaneously, the conjugated backbone creates a high‑mobility pathway that augments TiO₂’s intrinsic electron conductivity. This dual action improves carrier extraction at the buried interface, reducing recombination losses and enabling more efficient charge collection.

The performance gains are striking: perovskite cells built on IDT‑R‑modified TiO₂ deliver a 25.38% power conversion efficiency, surpassing the best TiO₂‑based records and approaching the theoretical limits of the material system. Moreover, the devices exhibit enhanced thermal stability, a critical hurdle for real‑world deployment. The breakthrough demonstrates that diradical semiconductors can serve as powerful interfacial modifiers, opening new avenues for scaling perovskite photovoltaics and inspiring further exploration of radical‑based transport layers in other optoelectronic technologies.