Cu 2 ZnSn(S,Se) 4 (CZTSSe) is considered as
the promising absorbing layer materials for solar cells due
to its earth-abundant constituents and excellent semicon-
ductor properties. Through solution-processing, such as
various printing methods, the fabrication of high perfor-
mance CZTSSe solar cell could be applied to mass
production with extremely low manufacturing cost and
high yield speed. To better fulfill this goal, environmental-
friendly inks/solutions are optimum for further reducing
the capital investment on instrument, personnel and
environmental safety. In this review, we summarized the
recent development of CZTSSe thin films solar cells
fabricated with benign solvents, such as water and ethanol.
The disperse system can be classified to the true solution
(consisting of molecules) and the colloidal suspension
(consisting of nanoparticles).Three strategies for stabiliza-
tion (i.e., physical method, chemical capping and self-
stabilization) are proposed to prepare homogeneous and
stable colloidal nanoinks. The one-pot self-stabilization
method stands as an optimum route for preparing benign
inks for its low impurity involvement and simple
procedure. As-prepared CZTSSe inks would be deposited
onto substrates to form thin films through spin-coating,
spraying, electrodeposition or successive ionic layer
adsorption and reaction (SILAR) method, followed by
annealing in a chalcogen (S- or Se-containing) atmosphere
to fabricate absorber. The efficiency of CZTSSe solar cell
fabricated with benign solvents can also be enhanced by
constituent adjustments, doping, surface treatments and
blocking layers modifications, etc., and the deeper research
will promise it a comparable performance to the non-
benign CZTSSe systems.

• Cu 2 ZnSn(S,Se) 4 thin film solar cells fabricated with benign solvents