- 24months of implementation
- 13articles in ISI journals
- 33conference contributions
- 6outreach actions
In brief
NANODELL addressed one of the remaining challenges of “second-generation” solar cells based on AII–BVI semiconductor heterojunctions: collecting the photo-generated charge carriers more efficiently by rethinking the cell architecture. The project proposed a new “substrate”-type cell built exclusively from non-toxic, Zn-based chalcogenides, with a nanostructured back-electrode (NBE): a dense array of metallic nanowires standing vertically on the substrate and reaching into the absorber layer.
Beyond more efficient solar cells, the technologies developed in NANODELL open a route towards the large-scale fabrication of the next generation of nanostructured devices, with small dimensions but very large functional surfaces.
Main goal
To explore how nanowire-based back-electrodes can raise the efficiency of thin-film solar cells, with the ambition of outperforming a conventional cell made of the same materials without nanostructured electrodes.
Specific objectives
O1 – Electrochemical template synthesis platform. Controlled growth of vertically aligned nanowires with tunable aspect ratio and density: the first such system in Romania, set up at the MDEO Center.
O2 – Nanostructured back-electrodes. NBEs made of metals with different work functions (Au, Cu, Au:Cu), and the influence of nanowire density, length and diameter on the performance of NBE/ZnTe/ZnSe/ZnO/TCO solar cells.
O3 – Transparent top electrodes. The type and optimal thickness of the transparent conducting oxide (TCO) window electrode: indium- or aluminum-doped zinc oxide (IZO or AZO).
O4 – Dissemination. Sharing the results with specialists and the general public through publications, conferences and outreach.
Execution phases
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Phase 1 · 2020
Thin metallic films (Au, Au/Cu) by thermal evaporation in vacuum, and ZnS, ZnSe and ZnTe films by RF magnetron sputtering.
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Phase 2 · 2021
Cu nanowires grown in supported nanoporous alumina templates, and Cd-free reference solar cells based on Zn compound heterojunctions.
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Phase 3 · 2022
Back-electrodes of vertical Cu nanowires, absorber layers (CdTe, ZnTe) deposited on the nanowire arrays, and Cd-free solar cells built only from Zn-based heterojunctions.
Images: NANODELL project website.