Innovative Implementation of an Alternative Tetrathiafulvene Derivative for Flexible Indium Phthalocyanine Chloride-Based Solar Cells

• Published in: Micromachines (Basel) Vol. 12; no. 6; p. 633
• Main Authors: Hamui, Leon, Sánchez-Vergara, María Elena
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 29-05-2021; MDPI
• Subjects: Carrier mobility; Charge transfer; Chlorides; Heterojunction devices; Indium tin oxides; opto-electrical properties; Orbitals; organic semiconductor; Photoelectric effect; Photoelectric emission; Photovoltaic cells; Polyethylene terephthalate; Semiconductors; Solar cells; Spectrum analysis; Strong interactions (field theory); Substrates; tauc band; thin film; Vacuum thermal evaporation; United States > US; Mexico
• ISSN: 2072-666X; 2072-666X
• DOI: 10.3390/mi12060633

Herein, we present the photovoltaic properties of an indium phthalocyanine chloride (InClPc)-based flexible planar heterojunction device, introducing the tetrathiafulvene derivative 4,4′-Dimethyl-5,5′-diphenyltetrathiafulvalene (DMDP-TTF) as the electron donor layer. UV-vis spectroscopy is widely used to characterize the electronic behavior of the InClPc/DMDP-TTF active layer. The interactions between the DMDP-TTF and phthalocyanine are predominantly intermolecular and the result of the aggregation of InClPc. Tauc bands were obtained at 1.41 and 2.8 eV; these energy peaks can result in a charge transfer ascribed to the transition from the DMDP-TTF to π-orbitals that are associated with the phthalocyanine ring or even with the same indium metal center. Conductive carbon (CC) was used for the cathode. Finally, an indium tin oxide (ITO)/InClPc/DMDP-TTF/CC device was fabricated by high-vacuum thermal evaporation onto a flexible substrate and the photovoltaic properties were evaluated. A diode type I-V curve behavior was observed with a photovoltaic response under illumination. A generated photocurrent of 2.25 × 10−2 A/cm2 was measured. A conductivity reduction with the incident photon energy from 1.61 × 10−7 S/cm to 1.43 × 10−7 S/cm is observed. The diode resistance presents two different behaviors with the applied voltage. A VTFL of 5.39 V, trap concentration of 7.74 × 1016 cm−3, and carrier mobility values of ~10−6 cm2/V s were calculated, showing improved characteristics via the innovative implementation of an alternative TTF-derivative, indicating that the DMDP-TTF has a strong interaction at the junction where free available states are increased, thus inducing higher mobilities due to the large number of π-orbitals, which indicates the feasibility of its use in solar cells technology.