Ligand-mediated suppression of Ostwald ripening enables low-temperature sol-gel ZnO for efficient inverted flexible organic photovoltaics (opens in new tab)

Inverted flexible organic solar cells (F-OSCs) require low-temperature processing, but sol-gel ZnO as widely used electron transport layers (ETLs) demand high-temperature annealing above 150 oC, limiting incompatibility with plastic substrates. Here we introduce a ligand-directed strategy using N,N-dimethylethylenediamine (DMEN) that stabilizes the precursor as discrete Zn–O–Zn clusters, suppresses Ostwald ripening, and lowers the crystallization barrier, thus enabling high-quality ZnO ETLs a...