ZnO hierarchical structures as sacrificial inclusions for enhanced performance under full sun and indoor light in bifacial dye sensitized solar cells

• Published in: Solar energy 2021-09, Vol.226, p.214-224
• Main Authors: Sasidharan, Swetha, Jagadeesh, Anooja, Pradhan, Sourava C., Nair, Balagopal N., Azeez Peer Mohamed, Abdul, Narayanan Unni, K.N., Soman, Suraj, Nair Saraswathy Hareesh, Unnikrishnan
• Format: Article
• Language: English
• Subjects: Bifacial dye sensitized solar cells; Building integrated photovoltaics; Charge transfer; Dye-sensitized solar cells; Dyes; Electrolytic cells; Electromagnetic absorption; Energy conversion efficiency; Flowers; Fluorescent lamps; Hierarchical structures; Inclusions; Indoor photovoltaics; Interfaces; Iodides; Light scattering; Performance enhancement; Perturbation methods; Photoelectric effect; Photovoltaic cells; Photovoltaics; Solar cells; Solar energy; Structural hierarchy; Surface roughness; Titanium dioxide; Zinc oxide; ZnO
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2021.08.030

[Display omitted] •Enhanced PCE under indoor light and full sun without affecting transparency.•PCE of 15.5% achieved under indoor illumination (1000 lux, CFL).•PCE improvement of 40% and 44% upon front and back illumination.•Enhanced LHE, as well as ηcc, contributed to better Jsc and PCE.•A novel strategy for enhancing PCE of bifacial DSSCs for BIPV applications. We have already demonstrated a facile strategy for improving light scattering in bifacial dye sensitized solar cells (DSSCs) through fugitive inclusions of ZnO micro-flowers leading to enhanced photovoltaic performance without adversely affecting the transparency (Sasidharan et al., 2020). In the present work, we were able to further ameliorate the light scattering properties by employing micron sized ZnO hierarchical structures (fibril and sheet like aggregates) as sacrificial inclusions. ZnO hierarchical structures being deposited over TiO2 active layer were selectively etched off, leaving behind imprints over the TiO2 layer, which act as scattering centers to enhance the photocurrent of DSSCs owing to the increased light absorption. The present strategy extends the possibility to improve the performance of DSSCs under both one sun (100 mW/cm2) as well as indoor/ambient light conditions without compromising transparency to larger extend. By employing this strategy on a 6 µm thick TiO2 photoanode and implementing it in a DSSC using N719 sensitizer and iodide/triiodie electrolyte, power conversion efficiency of 15.5% could be achieved under indoor illumination (1000 lx) from a compact fluorescent lamp. A detailed study of the charge transfer dynamics at various interfaces were carried out using a range of electrical and optical perturbation techniques.