DMSO Solution Processed Cu2ZnSnS4 Solar Cell with Open Circuit Voltage Reached 0.731 V

Kesterite Cu
2
ZnSnS
4
(CZTS) thin film solar cell has great potential as low cost and environmentally benign photovoltaic technology. Here, we report CZTS solar cells with the absorber fabricated from dimethyl sulfoxide (DMSO) molecular solution with simple chemicals CuCl, Zn(OAc)
2
, SnCl
4
and thiourea (Tu) as Cu, Zn, Sn, and S sources. Sulfurization of the DMSO solution processed kesterite structured precursor film results in CZTS absorber film with densely packed large grains and smooth and flatten surface. A champion CZTS device with an efficiency of 7.0% and a short current density of 18.8 mA/cm
²
, an open circuit voltage of 0.731V, and a fill factor of 49.8% has been achieved. The V
oc
of this device is the highest among all CZTS solar cells reported so far. The efficiency of the current device is mainly limited by the high resistance and recombination due to impurities on absorber surface and back contact. Tetter performance can be expected by further optimization of absorber fabrication condition.