Study of Plasmonic Behaviour in Small Molecule Low Donor Concentration Organic Solar Cell

Abstract

The main objective of this research work is to (i) fabricate well efficient small molecule low donor concentration organic solar cells (OSCs) using thermal vapor deposition technique (ii) improve the device performance by charge extraction and collection of charge carriers in device with the incorporation of cathode buffer layers (CBLs) (iii) enhance the optical absorption of light photons in the device with the insertion of metallic gold nanorods (AuNRs) synthesized using seed-mediated method, and (iv) study the plasmonic behaviour of OSC device incorporated with AuNRs. The aim of thesis is to study the electrical behaviour of fabricated OSC devices using current density-voltage characteristics. This thesis reports the fabrication of fullerene (C70) based OSC devices. TAPC is used as donor materials in these OSC devices. Two CBLs: LiF and MoO3 are used to improve charge extraction and better energy levels alignment in devices. AuNRs are incorporated in OSC devices to give plasmonic effects. Crystalline cubic phase of synthesized AuNRs is investigated by XRD technique and FTIR spectroscopy. FESEM analysis depicts the shape of synthesized AuNRs and also gives the device structure of fabricated OSCs. Optical measurements show the applicability of donor (TAPC) and acceptor (C70) organic materials for OSC device fabrication. Quenching effects of devices with incorporation of CBLs is found out using photoluminescence spectra at room temperature. The dielectric behavior dielectric constant, dielectric loss and ac conductivity measurements of OSC devices with insertion of CBLs are also carried out over a wide range of frequencies at different voltages. newline