Efficient and stable solution-processed planar perovskite solar cells via contact passivation

TLDR

Planar perovskite solar cells fabricated entirely by low‑temperature solution processing (<150 °C) promise simple manufacturing, flexible substrates, and tandem integration, but require an electron‑selective layer compatible with such processing. The authors aim to introduce a contact‑passivation strategy using chlorine‑capped TiO₂ colloidal nanocrystals to reduce interfacial recombination and strengthen interface binding in low‑temperature planar cells. They implement this by depositing a chlorine‑capped TiO₂ colloidal nanocrystal film as the electron‑selective layer during low‑temperature solution processing. The resulting devices achieve certified efficiencies of 20.1 % and 19.5 % for 0.049 cm² and 1.1 cm² active areas, and retain 90 % (97 % after dark recovery) of their initial performance after 500 h of continuous room‑temperature operation at maximum power point under 1‑sun illumination.

Abstract

Planar perovskite solar cells (PSCs) made entirely via solution processing at low temperatures (<150°C) offer promise for simple manufacturing, compatibility with flexible substrates, and perovskite-based tandem devices. However, these PSCs require an electron-selective layer that performs well with similar processing. We report a contact-passivation strategy using chlorine-capped TiO2 colloidal nanocrystal film that mitigates interfacial recombination and improves interface binding in low-temperature planar solar cells. We fabricated solar cells with certified efficiencies of 20.1 and 19.5% for active areas of 0.049 and 1.1 square centimeters, respectively, achieved via low-temperature solution processing. Solar cells with efficiency greater than 20% retained 90% (97% after dark recovery) of their initial performance after 500 hours of continuous room-temperature operation at their maximum power point under 1-sun illumination (where 1 sun is defined as the standard illumination at AM1.5, or 1 kilowatt/square meter).