Speaker
Description
The scope of this research line is to investigate a new class of ferroelectric (FE) oxides with tuned band-gap (Eg) to address multiple photovoltaic (PV) key-mechanisms that will enable to develop a groundbreaking approach to the design of solar cells (SC): i) Eg ≤1.5 eV optimized for solar radiance absorption; ii) Non-centrosymmetric structure upholding FE Polarization (P) >50 µC/cm2 and Tc >500 K; iii) Twofold percolative paths for independent transport of e- from h+ to minimize recombination.
The core concept of this project exploits the FE polarization (P) [LV16] to replace the archetypical p-n junctions by-passing barrier losses and enabling power output above Eg, to surpass the semiconductors efficiency limitations. Moreover, the typical resilience of oxides allow to overcome stability issues found on SCs based on organic frameworks. The comprehensive studies and optimization of a series of promising photo-sensitive double-perovskite-like oxides, are based on the formula A2B’B”O6 [DK18]. Systems already under research are Bi2ZnTiO6 [FF19] and Bi2Zn3/2Mo1/2O6 thin films. The R&D strategy involves proactive DFT calculations to run simulations of the materials and heterostructures with asymmetric interfaces to settle P and selective extraction of e- apart from h+. Attention is given to employ feasible thin films deposition methods, like rf-sputtering, standard glass or Si substrates and functional oxide buffers like LaNiO3; MoO3, ZnO and ITO [AM20]. Envisaging affordable, robust, “lead-free” and environmentally friendly all-oxide Solar Cell demonstrator compatible with industrial CMOS fabrication. FE oxides with low Eg have real potential for innovative applications in multi-source energy harvesting, photo-electrochemistry, photo-catalysis and a new opto-electronic actuators or sensors. This project is clearly motivated to contribute for developing energy harvesting processes from renewable and carbon-free sources like Solar; in definite alignment with the UN and EU Global Environmental and Climate Emergency Declarations.
Contact researcher: fabio.figueiras@fc.up.pt
References:
[DK18] D. Kim & al., PNAS 2018, 115, 26, 6566-6571.
[FF19] F. Figueiras & al., J. Mater. Chem. A 2019, 7, 10696-10701.
[LV16] P. Lopez-Varo & al., Physics Reports 2016, 653, 1-40.
[AM20] A. Mahapatra & al., J. Mater. Chem. A 2020, 8, 27-54.
