Regular Article

New electron donor in planar heterojunction: optimization of the cells efficiency through the choice of the hole-extracting layer^★

¹ Laboratorio de síntesis Química, Departamento de Química y Biología, Facultad de Ciencias Naturales, Universidad de Atacama Copayapu, 485 Copiapó, Chile
² Université Oran1 — Ahmed Ben Bella, LPCMME, BP 1524 ELM Naouer, 31000 Oran, Algerie
³ MOLTECH-Anjou, CNRS, UMR 6200, Université de Nantes, 2 rue de la Houssinière, BP 92208, Nantes 44000, France
⁴ Institut des Matériaux Jean Rouxel (IMN), CNRS, UMR 6502, Université de Nantes, 2 rue de la Houssinière, BP 32229, 44322 Nantes cedex 3, France

^* e-mail: kbenchouk08@gmail.com

Received: 5 December 2019
Received in final form: 15 February 2020
Accepted: 2 March 2020
Published online: 17 April 2020

Abstract

Due to their light weight, flexibility and semi-transparency the organic photovoltaic cells play an important role for solar conversion photovoltaic (OPV). To achieve good performances, both donor and acceptor materials in OPVs need to have good extinction coefficients, high stabilities and good film morphologies. Since the donor plays a critical role as the absorber to solar photon flux, donor materials require wide optical absorption to match the solar spectrum. In this work the couple ED/EA in planar heterojunction was Tetracyano 4,4'-bis(9Hcarbazol-9-yl) biphenyl (TCC)/fullerene (C₆₀). Optimum results are obtained when MoO₃ alone is used as Hole Transporting Layer (HTL). The J/V characteristics do not exhibit S-shaped curves up to a TCC layer thickness of 15 nm, while they did when the HTL includes CuI. Theoretical study, complementary to the experimental study, shows that in the case of S-shaped curve the cell behaves as if it was made up of 2 diodes, one of which would be opposed to the flow of the photogenerated current. In the case of MoO₃ HTL, i.e; without shaped curve, the optimum thickness is 13 nm, giving an efficiency η = 2.30% with V _oc = 0.9 V, J _sc = 5.17 mA/cm² and FF = 49%.