Work

An all‐polymer blend for photovoltaic applications: A combined photoabsorption, photoemission and ab initio multi‐configurational study

Year: 2026

Type: article

Abstract: We have investigated the electronic structure and morphology of thin films of the electron‐donor poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexylthio)‐4‐fluorothiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b']dithiophene))‐ alt ‐(5,5(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′]dithiophene‐4,8‐dione)] (PBDB‐T‐SF), the non‐fullerene acceptor (NFA) poly[[1,2,3,6,7,8‐hexahydro‐2,7‐bis(2‐octyldodecyl)‐1,3,6,8‐dioxobenzo[ lmn ][3,8]phenanthroline‐4,9‐diyl][2,2′‐bithiophene]‐5,5′‐diyl] (P(NDI2OD‐T2)) and their blend. Angle‐resolved near‐edge X‐ray absorption fine structure (NEXAFS) in total electron yield detection mode was employed to probe the C 1s, N 1s and S 2p absorption edges. The results indicate a preferential face‐on orientation of the naphthalene diimide unit in the acceptor, and an edge‐on orientation for the thiophene rings. A preferential edge‐on orientation was also observed for the electron‐donor polymer. Analysis of the blend's NEXAFS spectra suggests an accumulation of the NFA component on the surface of the film. The investigated films were also characterized by X‐ray photoelectron spectroscopy (XPS), attesting the presence of thiophene in all the samples and imide in the films containing the NFA polymer. The XPS results further indicate that the acceptor material is accumulated in the surface of the blend film. Finally, the analysis was complemented by ab initio calculations at the multi‐configurational level for transitions at C 1s, N 1s and S 2p absorption edges, with spin–orbit effects included for the latter. © 2026 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Source: Polymer International

DOI: 10.1002/pi.70132

Authors: Cássia Ferreira Coutinho Pereira, Luís Felipe de Lima Pimentel, Alexandre B. Rocha, Maria Luiza M. Rocco

Institution: Universidade Federal do Rio de Janeiro

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: hybrid

Estimated APC paid: $3,890