Hybrid Organic-Inorganic Solar Cells with Electrodeposited Al-Doped Zinc Oxide

Hybrid solar cells were fabricated using aluminum-doped zinc oxide (AZO) grown by electrochemical deposition from chloride electrolyte solutions with Al/Zn molar ratios of 0.5, 2.5, and 5.0%. The substrates were AZO- and ZnO-seeded ITO. Ordered nanorod structures with high optical transmittance were grown at 0.5% Al/Zn ratio while interconnected micron-sized flakes were grown at 2.5% and 5.0%. The estimated band gap energies increase for higher Al dopant content, showing Burstein-Moss effect. EDX analysis detected high aluminum content in the 5.0% samples suggesting that insulating aluminum oxide phases were formed thus causing reduced solar cell efficiencies. The highest power conversion efficiency of 1.71%, from the 0.5% sample grown on ZnO-seeded ITO, can be attributed to the presence of AZO nanorods which provide a large interfacial area and effective charge transport.