Polycrystalline-semiconductor nanofilm-electrodes emerged as easy-to-prepare, low-cost and environmentally-friendly alternatives to photovoltaics. Nanofilm electrodes are unstable with low-cell performance. Strategies were proposed to enhance solar-cell performance. Heterojunction-solar cells were reported with ternary and quaternary CuInGaS (CIGS) materials that have costly constituents. Minimizing CIGS-layer thickness, is investigated by adding CuZnSnSSe (CZTSSe). Tandem CIGS nanofilm cells are studied. Top sub-cells involved wide bandgaps for short wavelengths, while bottom sub-cell involved narrower gaps. Other film electrodes involve dye-sensitized solar cells (DSSCs). Tremendous publications appeared by varying the semiconductor (using TiO₂, ZnO, ZnTiO₃, etc.), the dye (metal-based, metal-free and natural dyes) and the counter electrodes. Other nanofilm electrodes, such as metal chalcogenides (MX: M is Cd, Cu, Zn; X is S, Se, Te or even O), with middle to narrow band gaps (1.5 - 2.5 eV), were improved by simple methods.  Careful choice of annealing temperature suitable for film material, followed by careful choice of cooling rate, are necessary. Based on earlier reports, semiconductors with medium band gap values, may not be thermodynamically stable. Method of annealing, as continuous vs. pulse heating, should be examined.  Annealing enhances semiconductor film properties (crystallinity, particle size, sintering, carrier mobility and overall cell performance) as annealing lowers crystallite imperfections and brings metastable atoms back to stable positions. Cooling rate may also affect the solar cell performance. Slow cooling may improve the semiconductor characteristics. Higher temperature annealing needs rapid or quenched. Our earlier results in the area will be discussed. Suitability of these methods to CIGS/CTZSSe and to DSSCs is under investigation. Attaching charge transfer catalysts to semiconductor surface, is useful. The species shifted the flat-band potential by 300 mV. The short circuit current was improved by quick release of holes (in the space-charge layer). The semiconductor surface was stabilized. Combining all these strategies together gave highest performance.  Unprecedented conversion efficiencies 4.4, 8.0, 15.0 and 18.0% were observed from CdSe, CdTe, CuS and CuSe electrodes, respectively. Results and model will presented.  Future prospects of this work will also be discussed.

Conference Title

International Conference on Advances in Mechanical Engineering (ICAME 2024)

Conference Country

Turkey

Conference Date

Dec. 23, 2024 - Dec. 26, 2024

Conference Sponsor

Yildiz Technical University

Additional Info

Conference Website