Highly efficient dye‐sensitized solar cells for wavelength‐selective greenhouse: A promising agrivoltaic system

Abstract

Summary In trying to solve simultaneously the energy and food crisis, the concept proposed by Agriculture 4.0, namely a combination between the agriculture and the solar energy could provide a possible solution. The wavelength‐selective greenhouse could be a promising agrivoltaic system if the trade‐off between photovoltaic roofs and plants will be achieved. Using less studied solar cells as an electricity source for an autonomous greenhouse, this study has demonstrated experimentally that the requirements imposed by a greenhouse can be provided by a DSSC using an affordable commercial yellow dye. The successful implementation of DSSC in autonomous greenhouses is conditioned by three main requirements, and that are the transparency of the entire Photosynthetic Active Radiation (PAR) domain along with high UV absorption, high efficiency of the solar cell, and sustainability during the whole year. The best DSSC has proved a high absorption of UV radiation, closely by 90%, a transparency of the DSSCs preserved on the whole PAR domain and achieved a photovoltaic efficiency two times higher than the best efficiency reported for this dye so far. Furthermore, by preserving the maximum efficiency of almost 5% under the light intensity in the range 50 to 100 mW/cm2, the sustainability of our DSSC over the whole year has been demonstrated.

Towards the thermal stability of dye-sensitized solar cells for wavelength-selective greenhouses using the polymorphism of light-scattering layers

“…DSSCs without and with a brookite TiO 2 -based light-scattering layer (henceforth named DSSC_1 and DSSC1_BLS, respectively) were carried out according to our previous work. 16 In this case, the DSSC_1 photoanode with 0.75 μm thickness consists of 3 layers prepared as follows: (i) the first compact layer of TiO 2 as a blocking layer, obtained by spin-coating a solution of 1 : 5 titanium diisopropoxide bis(acetylacetonate) (75 wt% in isopropanol) in tert -butanol (99.8%, Sigma-Aldrich) followed by calcination at 450 °C for 60 minutes at a rate of 1 °C min −1 ; (ii) the second layer consists of TiO 2 nanoparticles crystallized in an anatase form, obtained by a hydrothermal method at 100 °C for 12 h and calcination at 500 °C for 60 minutes at a rate of 1 °C min −1 ; and (iii) the final treatment with 40 mM TiCl 4 is applied on the photoanode surface and sintered at 450 °C for 1 h.…”

“…The photoanode and platinized counter electrode obtained by deposition of H 2 PtCl 6 followed by calcination at 400 °C for 30 min were encapsulated using a Meltonix 1170-60 thick spacer. According to our previous work, 16 two different electrolytes were used to fill the space between the electrodes, namely, the electrolyte E1, which consists of a solution of 0.6 M 1-butyl-3-methyl-immidazolium iodide, 0.03 M I 2 , 0.10 M guanidinium thiocyanate and 0.5 M 4 tert -butylpyridine in acetonitrile/valeronitrile (85/15) and the electrolyte E2 that differs only in the I 3 − /I − ratio (2 M 1-butyl-3-methyl-immidazolium iodide and 0.05 M I 2 ).…”

“…The crystalline phase and morphological structure of TiO 2 polymorphs have been explained in detail in our previous work. 16,19 In Fig. 1, the anatase, brookite, and rutile crystalline phases used as light-scattering layers are highlighted, and Table 1 summarizes the structural parameters.…”

“…In this context, our previous work has experimentally demonstrated that the requirements imposed by a greenhouse can be provided by a DSSC using a yellow dye and a complex architecture of TiO 2 photoanode with a brookite light-scattering layer as follows: (i) a conversion efficiency of 4.91% for 1 sun illumination, two times higher than the best efficiency reported for the same dye until then; 15 (ii) partially transparency throughout the PAR domain; (iii) a coverage rate of 100% and (iv) a photovoltaic efficiency of nearly 5% at an irradiance between 50 mW cm −2 and 100 mW cm −2 , corresponding to the maximum light intensity in all seasons. 16 Based on these excellent premises, the next step in the largescale implementation of this concept is the optimization of yellow-based DSSCs for outdoor conditions. Thus far, the signicant previous research efforts on the thermal stability of DSSCs have only focused on studying more efficient visibleresponsive DSSCs, namely, the mechanisms of deterioration of visible absorbing dye molecules and electrolytes under outdoor conditions.…”

“…In this context, our previous work has experimentally demonstrated that the requirements imposed by a greenhouse can be provided by a DSSC using a yellow dye and a complex architecture of TiO 2 photoanode with a brookite light-scattering layer as follows: (i) a conversion efficiency of 4.91% for 1 sun illumination, two times higher than the best efficiency reported for the same dye until then; 15 (ii) partially transparency throughout the PAR domain; (iii) a coverage rate of 100% and (iv) a photovoltaic efficiency of nearly 5% at an irradiance between 50 mW cm −2 and 100 mW cm −2 , corresponding to the maximum light intensity in all seasons. 16…”