A Nonvacuum Approach for Fabrication of Cu₂ZnSnSe₄/In₂S₃ Thin Film Solar Cell and Optoelectronic Characterization

Abstract

Cd-free kesterite-based Cu 2 ZnSnSe 4 (CZTSe)/In 2 S 3 champion solar cell of 5.74% efficiency has been fabricated by chemical spray pyrolysis. In this fabrication route, CZTSe absorber layer was sprayed by using a precursor solution, where metallic salts were dissolved in water-based solvent and subsequently selenized with Se powder at high temperature. In 2 S 3 buffer as an alternative to CdS buffer was also deposited by chemical spray pyrolysis. The device characteristics were studied by measuring dark/light illuminated J−V−T, external quantum efficiency, temperature dependence of open circuit voltage (V OC ) and series resistance (R s ), and admittance spectroscopy. The performance of sprayed CZTSe/ In 2 S 3 solar cell was found to be limited by high back-contact barrier potential, poor carrier collection, and detrimental intrinsic defect states in device.

Band Gap Tuning of Cu2ZnGeSxSe4-x Absorbers for Thin-Film Solar Cells

“…The most likely explanation for the decreasing thickness is that, as S-inclusion increases, the MoSxSe2-x forms a barrier for the diffusion of bigger Se ions, thereby inhibiting further growth of the layer. Additionally, two more modes were observed: a very weak mode at 147 cm −1 that could not be attributed to the kesterite or any secondary phase and a sharper mode at 221 cm −1 that was previously reported for CZGSSe [17]. The latter one is especially interesting since it became the most intense mode when the Figure 2b).…”

“…However, in comparison to the cited publications, all modes were slightly shifted due to the mixed sulfoselenide composition. Additionally, two more modes were observed: a very weak mode at 147 cm −1 that could not be attributed to the kesterite or any secondary phase and a sharper mode at 221 cm −1 that was previously reported for CZGSSe [17]. The latter one is especially interesting since it became the most intense mode when the [S]/([S] + [Se]) ratio was increased to 0.37.…”

“…In the complete spectrum, the 112-reflection at 28.04 is the strongest kesterite reflection. Additional reflections can be seen at 17 …”

High potential for the optimum designs for a front contact and junction: A route to heterojunction solar cell

“…The obtained crossover point is usual for the devices offering high resistive losses. A similar crossover point was reported by Khadka et al [16] for solution processed Cu 2 ZnSnS 4 /In 2 S 3 thin film solar cell. In our fabricated device, a relatively lower FF and the crossover point can be attributed to the higher value of R S , which possibly arises from either back Al/Si contact, or the higher resistivity of AgNWs embedded ITO layer.…”

Cross‐Section Analysis of the Composition of Sprayed Cu2ZnSnS4 Thin Films by XPS, EDS, and Multi‐Wavelength Raman Spectroscopy

“…Since the pioneering report presented by Nakayama et al, many works have been published. Most of them address the preparation of CZTS films by spray pyrolysis, generally obtained from aqueous solutions, alcohol–water mixtures, or from pure organic solvents . Average efficiencies for sprayed kesterite photovoltaic (PV) devices are between 0.55% and 4%, but Larramona et al have reported a 5% efficient pure sulfide CZTS solar cells sprayed from water–ethanol colloidal dispersions and, recently, a 10.6% solar cell device of CZTSSe composition (with Se addition during thermal treatment) .…”