Nasejje, StellaMushebo, EmmanuelBirabwa, Denise JoanitahDiale, M. (Mmantsae Moche)Mukhokosi, Emma Panzi2026-03-252026-03-252026-01-05Nasejje, S., Mushebo, E., Birabwa, D.J. et al. 2026, 'Biosynthesized nickel oxide honeycomb nanostructures for DSSC counter electrode : a joint experimental and density functional theory study', Materials Research Express, vol. 13, no. 1, art. 15001, pp. 1-16, doi : 10.1088/2053-1591/ae2f27.2053-1591 (online)10.1088/2053-1591/ae2f27http://hdl.handle.net/2263/109282DATA AVAILABILITY STATEMENT : All data that support the findings of this study are included within the article.The urgent need to address fossil fuel challenges has led to a surge in green energy technologies, including solar cells. Nanodimensional particles, particularly 2D nanostructures, have shown great potential in these technologies due to their high surface area-to-volume ratio. Nickel oxide (NiO) is a promising p-type semiconductor for solar cell photo-cathodes, offering remarkable physical and chemical properties at a relatively low cost. However, its surface morphology, area, and pores have a significant impact on performance. Traditional chemical synthesis methods for NiO nanostructures have several drawbacks, including the use of hazardous precursors. To address this, we present for the first time a novel bioengineering method using bamboo shoot extract to produce 2D NiO nanostructures. The results have been supported by Density Functional Theory (DFT) calculations. The DFT calculations revealed that NiO is a p-type semiconductor with direct band gap for spin-down at Г. The results show that the bioengineered NiO nanostructures exhibit high crystallinity and a honeycomb-like morphology. We successfully integrated these nanoparticles into a dye-sensitized solar cell (DSSC), demonstrating their viability as a counter electrode. The cell exhibits promising performance, with a short-circuit current density of 0.113 mA cm−2 and an efficiency of 0.0057%. This study presents a straightforward, cost-effective, and environmentally friendly method for bioengineering NiO honeycomb-like nanostructures, thereby paving the way for sustainable energy solutions.en© 2026 The Author(s). Published by IOP Publishing Ltd. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence.Nickel oxideBiosynthesisDye-sensitized solar cells (DSSC)Bamboo shootDensity functional theory (DFT)Article