Akademik Veri Yönetim Sistemi
Asil Alptekin D. (Yürütücü)
TÜBİTAK Uluslararası İkili İşbirliği Projesi, 2023 - 2025
The theoretical efficiency photovoltaic (PV) devices is thermodynamically limited up to 33%. One of the key loss mechanisms for this so-called Shockley-Queisser (SQ) limit arises from ultrafast ~ ps energy dissipation in energetic hot carriers generated via far-beyond bandgap optical excitations by ultraviolet photons. Solar cells that have ability to generate multiple pair of electrons and holes by energetic photons via e.g. multiple exciton generation (MEG) could potentially circumvent the energy loss issue by hot carrier relaxations, and thus hold a great potential for new-generation PV devices going beyond the SQ limit. The reported photoconversion efficiencies (PCEs) exploiting the MEG concept, on the other hand, remains moderate, which calls for further efforts in both device integrations and understanding the underlying photo-physics. The processes of photoexcited carrier (or exciton) generation, extraction and transport have known to play major roles in determining the PV performance of the solar cells. Therefore, in order to further enhance the PV performance parameters of the solar cells, it is crucial to gain a deep understanding of those photoexcited carrier dynamic processes. Based on nanomaterials with high MEG yields, i.e, PbSe QDs and PbSe NRs, the applicant at Turkey side has recently developed and demonstrated bulk nano heterojunction (BNHJ) solar cells with external quantum yields beyond unity. Benefited from the strong expertise of the Germany partner at MPIP in advanced time-resolved spectroscopes, the aim of the project is to investigate the charge carrier dynamics between QD-NR donor-acceptor (D:A) units to optimize the MEG effect for PVs. In particular, our main goal is to shed light on the MEG and multiple exciton dissociation (MED) mechanisms in the NR-QD hybrids, and establish correlation between spectroscopic results with the BNHJ solar cell performance (with the aim to further improve the PV performance of the MEG-based solar cells currently produced by the Turkish team).