Work

Controlling Charge Generation in Organic Photovoltaic Ternary Blends: How Trace Ternary Additives Determine Mechanism

Year: 2025

Type: article

Abstract: A series of modified tetraphenylporphyrins varying only in the electron-donating or electron-withdrawing character of the substituents in the para-phenyl position have been blended into the active layer of MEH-PPV:PCBM bulk heterojunction solar cells. Increasing the electron-withdrawing ability of the substituents, as quantified by the Hammett constant, systematically alters the device efficiency of ternary poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene]:porphyrin:[6,6]-phenylC61-butyric acid methyl ester (MEH-PPV:porphyrin:PCBM) bulk heterojunction organic solar cells through alteration of the HOMO/LUMO levels and, thereby, the open-circuit voltage of the cell. We show that the porphyrin concentrates at the MEH-PPV:PCBM interface in these blends and that the devices operate via a cascade mechanism when the highest occupied molecular orbital (HOMO) of the porphyrin is higher in energy that that of MEH-PPV, but via a parallel/alloy device mechanism, when the HOMO of the porphyrin is lower in energy than that of MEH-PPV. As such, this work highlights how the energetics of the ternary component can determine device performance by switching between charge generation models simply by altering the electron-withdrawing character of the porphyrin ternary additive.

Source: Electronics

DOI: 10.3390/electronics14081655

Authors: Nathan A. Cooling, Krishna Feron, Timothy W. Jones, Warwick J. Belcher, Paul C. Dastoor

Institutions: University of Newcastle Australia, Commonwealth Scientific and Industrial Research Organisation

Language: English

Topic: Organic Electronics and Photovoltaics

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: gold

Estimated APC paid: $2,896