Indium Sulfide Thin Film Technologies for Photovoltaic Applications

Indium sulfide (In₂S₃) has emerged as a versatile semiconductor for thin film photovoltaics, serving principally as a buffer or window layer in a range of device architectures. Its tunable bandgap (typically 2.0–2.3 eV), high absorption coefficient and chemical stability make it attractive for both standalone and tandem cells. Thin films of In₂S₃ can be deposited by chemical bath deposition, spray pyrolysis, thermal evaporation and sulphur‐ambient annealing, yielding α, β and γ polymorphs with distinct crystallographic and optoelectronic properties. Doping strategies – including copper, vanadium, niobium and titanium – enable bandgap modulation, defect engineering and the creation of intermediate bands to enhance sub‐bandgap absorption. Nanostructured forms such as nanoflakes, quantum dots and two‐dimensional nanosheets have been explored to increase surface area, improve light harvesting and facilitate charge extraction. Heterojunctions of In₂S₃ with silicon or perovskite absorbers are under active development, offering low‐cost, scalable routes to high‐efficiency solar cells with reduced toxic elements and simplified manufacturing.

Research from Nature Portfolio

Innovative fabrication via sulphur‐ambient annealing of indium films has been shown to produce high‐quality In₂S₃ thin films with controlled phase purity and morphology. By systematically varying annealing temperature and chamber pressure, researchers identified optimum conditions (550 °C, 100 Torr) that yield dense, phase‐pure β‐In₂S₃ layers. Structural analyses confirm uniform grain growth and stoichiometric composition, while photoluminescence and Raman spectroscopy indicate low defect densities. This scalable method promises cost-effective production of buffer layers for emerging photovoltaic technologies.

Indium Sulfide Thin Film Technologies for Photovoltaic Applications publication trend

The graph below shows the total number of articles in indium sulfide thin film technologies for photovoltaic applications across all publications each year (not limited to Nature Index journals).

Technical terms

Bandgap energy (Eg): The energy difference between the valence and conduction bands that determines the minimum photon energy a semiconductor can absorb.

Chemical bath deposition (CBD): A low-temperature, solution-based technique for growing thin films by controlled precipitation of precursor materials onto a substrate.

Intermediate band: A partially filled energy band within the bandgap of a semiconductor that enables absorption of sub-bandgap photons and potentially increases solar cell efficiency.

Heterojunction: An interface between two different semiconductor materials where charge separation and collection occur in photovoltaic devices.

Urbach energy: A parameter describing the width of the exponential tail of the absorption edge, related to disorder and defect states in a semiconductor.

References

1. New fabrication method for di-indium tri-sulfuric (In2S3) thin films. Scientific Reports (2022).
2. Elucidating the local structure of V substitutes in In2S3 as potential intermediate band material by x-ray absorption spectroscopy and first principles calculations. Journal of Physics Energy (2023).
3. The synthesis and the effect of Cu on optoelectronic qualities of β-In2S3 as a window layer for CIGS thin film solar cells. Results in Physics (2022).
4. Characterization of photovoltaics with In2S3 nanoflakes/p-Si heterojunction. Discover Nano (2014).
5. Towards intermediate-band photovoltaic absorbers: theoretical insights on the incorporation of Ti and Nb in In2S3. npj Computational Materials (2020).
6. Structure reinvestigation of α-, β- and γ-In2S3. Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials (2016).