There is a strong market driven need for processing organic photovoltaics from eco-friendly solvents. Water-dispersed organic semiconducting nanoparticles (NPs) satisfy these premises convincingly. However, the necessity of surfactants, which are inevitable for stabilizing NPs, is a major obstacle towards realizing competitive power conversion efficiencies for water-processed devices. Here, we report on a concept for minimizing the adverse impact of surfactants on solar cell performance. A poloxamer facilitates the purification of organic semiconducting NPs through stripping excess surfactants from aqueous dispersion. The use of surfactant-stripped NPs based on poly(3-hexylthiophene) / non-fullerene acceptor leads to a device efficiency and stability comparable to the one from devices processed by halogenated solvents. A record efficiency of 7.5% is achieved for NP devices based on a low-band gap polymer system. This elegant approach opens an avenue that future organic photovoltaics processing may be indeed based on non-toxic water-based nanoparticle inks.

Achieving the interfacial homogeneity and bulk crystallization for efficient and stable perovskite solar cells via ionic liquids.

A mesoporous layer was constructed by a donor-based nanoparticulate water-ink, which facilitates the infiltration of the acceptor, allowing the fabrication of efficient organic solar cells with a high thickness tolerance.

The development of efficient and stable wide-bandgap (WBG) bromine–iodine halide perovskites (Br > 20%) is crucial for enhancing the performance of tandem solar cells. Nonetheless, phase separation of I–Br in WBG perovskites under illumination and heating significantly hinders the advancement of tandem devices. This phenomenon is primarily attributed to the uneven spatial distribution of halide ions in WBG films. Moroxydine hydrochloride was introduced into 1.85 eV I–Br mixed WBG perovskite films, effectively optimizing the crystallization dynamics of the perovskite and improving the film stability. Through this approach, a 1.85 eV WBG perovskite solar cell (PSC) was successfully fabricated, achieving a power conversion efficiency (PCE) of 18.76%, an open-circuit voltage (V_OC) of 1.387 V, and remarkable operational stability. When applied to perovskite–organic tandem solar cells, this method led to devices with a PCE of 25.98% and a V_OC of 2.210 V, setting a new record for the highest V_OC reported to date.