Abstract
Kesterite Cu2ZnSnS4 (CZTS) nanostructure is synthesized without the sulfurization process using a solvothermal technique. The induced effects in the optical properties of the fabricated film of this nanostructure are studied. As XRD analysis revealed the as-prepared film is polycrystalline in nature which indexed in the tetragonal Kesterite structure of the CZTS phase. Optical properties related to solar cell parameters, such as absorption coefficient, penetration depth, Urbach energy, and energy band gap are studied. The absorption coefficient of 1.5 × 105 cm−1 is observed at 1.5 eV, which matches the optimum bandgap of the solar spectra. The penetration depth as a function of photon energy for CZTS is shown. Al/Si/CZTS/Al heterojunction photovoltaic cell is fabricated. The as-prepared fabricated cell shows a low short circuit current (Isc) of 1.5 mA and a low fill factor (FF) of 27.2%. Upon the annealing at 350 °C in the N2 atmosphere without any sulfurization, the cell performance was much enhanced, where the ISC improved up to 8.9 mA and the FF up to 33.5%. In addition, dramatic improvement in the power conversion efficiency (η) was observed from 0.91% up to 6.72% for the as-prepared and annealed cell, respectively.
•CZTS was synthesized without sulfurization process.•The annealing was done in N2 without sulfurization.•The efficiency of annealed cell is 6.72%.