Our colleagues Šimun Mandić, Ana Senkić, and Nataša Vujičić have published a paper in the prestigious journal Surfaces and Interfaces, where they investigated the impact of thin-film deposition of organic molecules on the optical properties of 2D materials.
The optical properties of two-dimensional (2D) semiconductors can be modified in various ways, such as through doping, substrate bending, or molecular deposition.
In this work, we explored how a thin layer of the organic H2Pc molecule modifies optical properties—such as photoluminescence and vibrational Raman spectra—of the 2D semiconductors MoS2 and WS2.
In such hybrid materials containing both organic molecules and inorganic semiconductors, two interaction processes are most likely: charge transfer and energy transfer (known as Förster resonant energy transfer, or FRET).
In the case of the H2Pc/MoS2 material, the dominant process is the transfer of free electrons from MoS2 to H2Pc. This was established using complementary optical, structural, and electrostatic techniques, as well as low-temperature optical measurements. In addition to charge transfer, H2Pc plays a major role in improving the quality of MoS2, as shown by the observed successful “defect healing” process, where the molecule occupies a defect site on the substrate, neutralizing it. This result demonstrates that this type of modification of 2D materials can be used as an effective method for restoring the quality of 2D materials that have been exposed to atmospheric conditions for extended periods.
On the other hand, in the H2Pc/WS2 sample, the dominant interaction process is FRET, which is evident in the emission spectrum showing contributions from both components—unlike in the H2Pc/MoS2 material. This type of interaction is only possible under resonant conditions: the molecule must efficiently absorb the light emitted by WS2. For this reason, the emission intensity of WS2 is reduced after molecule deposition.
Analysis of the vibrational Raman spectra of the organic molecule confirmed the different interaction mechanisms in these two hybrid materials.
This research shows that the interaction between organic molecules and 2D materials depends on fine details of the material’s electronic structure, the presence of defects, and the influence of their dipole moments. This is crucial for the design and performance of future optoelectronic devices, as it enables control over charge and energy transfer within heterostructures, as well as over the quality and stability of 2D materials.
The paper was published in the prestigious journal Surfaces and Interfaces and was largely conducted at the Institute of Physics, with contributions from Prof. Đerek of the Physics Department at PMF for the deposition of molecules onto two-dimensional semiconductors.
Details on the paper are available: doi.org/10.1016/j.surfin.2026.108444
Defect healing and Förster resonant energy transfer in H2Pc-TMD organic-inorganic heterostructures
Šimun Mandić, Ana Senkić, Nataša Vujičić, Surfaces and Interfaces 82, 108444 (2026)
