Low Cost Pyrite (Fes₂) Nanorod Sensitized Solar Cell​

Abstract

Abstract. The fabrication of a low cost, sustainable semiconductor sensitised solar cell is carried out using FeS 2 nanorods as the sensitising material over an electrode coated by TiO 2 nanoparticles. Though the semiconductor sensitised cells are eloquently researched, NR structures as a sensitising material are still not fully investigated despite their features potentially beneficial for accelerating the performance of the devices. The pyrite NR based solar cell is having a notable open circuit voltage of 0.16 V, a short circuit current of 3.9 mA/cm 2 and an overall conversion efficiency of 0.63%. A simple design and fabrication approach like doctor blading, dip coating is employed throughout the work with an objective to minimise the fabrication cost as much as possible.Keywords: Pyrite solar cells; FeS 2 ; nanorods; cheap photovoltaics; photoelctrochemical cell. IntroductionThe thin film PV modules photovoltaics market continues to show immense promise these days, but is presently dominated by product based on the use of materials like CdTe, GaAs and silicon wafers, similar to those used in microelectronics. Though the CdTe and GaAs thin film PV modules have the potential to reach cost effective PV-generated electricity, their toxicity and adverse effects on environment drag their feet. [7] have reported the modification of large band gap TiO 2 (Degussa P25) by quantum-sized FeS 2 particles by a similar procedure described by Chatzitheodorou et al. [8]. They reported an incident-photon-to current efficiency of 25% at 400 nm excitation. Despite various possibilities of the ex-situ assembly route, like sensitizers of different sizes, shapes, and compositions, most efforts in this area are focused on the 0-D semiconductor QDs as sensitizer materials [9,10]. In this work we have sensitised FeS 2 nanorods(NRs) of diameter 12 nm on a TiO 2 layer coated over ITO substrate with I / I 3 -and Pt as the electrolyte and the counter electrodes respective. Throughout this work we have adopted the most simple and cost effective methods for the fabrication of solar cells.The NR structures open up various possibilities such as band gap tuning by varying the diameter of the NRs along the length [10], orthogonal light absorption and carrier collections directions, minimisation of the recombination of photogenerated carriers by proper channelizing of the carriers [11] in an oriented direction etc. , thus reducing the thickness of the absorber layer in such nano-structured solar cells to several hundred nanometers relatively to the traditional thin film solar cells. Also the increased semiconductor surface area in NRs improves the semiconductor-electrolyte interface [11,12,13] and thus creates more photocatalytic reactive sites which is supposed to create better hole transport. The NR structures further show enhanced strain relaxation [14,15] opening up to a broader range of absorption energies than is possible with other planar structures.