Conductive colloidal perovskite quantum dot inks towards fast printing of solar cells

Quantum dot (QD) provides a versatile platform for high-throughput processing of semiconductors for large-area optoelectronic applications. Unfortunately, the QD solar cell is hampered by the time-consuming layer-by-layer process, a major challenge in manufacturing printable devices. Here we demonstrate a sequential acylation-coordination protocol including amine-assisted ligand removal and Lewis base-coordinated surface restoration to synthesize conductive APbI3 (A = formamidinium (FA), Cs or methylammonium) colloidal perovskite QD (PeQD) inks that enable one-step PeQD film deposition without additional solid-state ligand exchange. The resultant PeQD film displays uniform morphology with elevated electronic coupling, more ordered structure and homogeneous energy landscape. Narrow-bandgap FAPbI3 PeQD-based solar cells achieve a champion efficiency of 16.61% (certified 16.20%), exceeding the values obtained with other QD inks and layer-by-layer processes. The conductive PeQD inks are compatible with large-area device (9 × 9 cm2) fabrication using the blade-coating technique with a speed up to 50 mm s−1.