Faruk Ozel

Dye-Sensitized Cu2XSnS4 (X=Zn, Ni, Fe, Co, and Mn) Nanofibers for Efficient Photocatalytic Hydrogen Evolution

The photocatalytic hydrogen evolution activities of low-cost and noble-metal-free Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofiber catalysts have been investigated using triethanolamine as an electron donor and eosin Y as a photosensitizer under visible-light irradiation. The rates of hydrogen evolution by Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofibers have been compared with each other and with that of the noble metal Pt. The hydrogen evolution rates for the nanofibers change in the order Cu2 NiSnS4 >Cu2 FeSnS4 >Cu2 CoSnS4 >Cu2 ZnSnS4 >Cu2 MnSnS4 (2028, 1870, 1926, 1420, and 389 μmol g(-1) h(-1) , respectively). The differences between the hydrogen evolution rates of the nanofibers could be attributed to their energy levels. Moreover, Cu2 NiSnS4, Cu2 FeSnS4 , and Cu2 CoSnS4 nanofibers show higher and more stable photocatalytic hydrogen production rates than that of the noble metal Pt under long-term irradiation with visible light.

Photocatalytic hydrogen evolution based on Cu2ZnSnS4, Cu2ZnSnSe4 and Cu2ZnSnSe4−xSx nanofibers

New photocatalytic systems for hydrogen evolution from water have been reported by using low cost and environmentally-friendly Cu2ZnSnS4, Cu2ZnSnSe4, and Cu2ZnSnSe4−xSx nanofiber catalysts in the presence of eosin Y as a photosensitizer and a sacrificial reducing agent triethanolamine under visible light irradiation. The rate of hydrogen evolution with Cu2ZnSnS4 is greater than those with Cu2ZnSnSe4 and Cu2ZnSnSe4−xSx, producing hydrogen at 1428 μmol g−1 h−1, 833 μmol g−1 h−1 and 739 μmol g−1 h−1, respectively.

Enhanced Device Efficiency and Long-Term Stability via Boronic Acid-Based Self-Assembled Monolayer Modification of Indium Tin Oxide in a Planar Perovskite Solar Cell

Interfacial engineering is essential for the development of highly efficient and stable solar cells through minimizing energetic losses at interfaces. Self-assembled monolayers (SAMs) have been shown as a handle to tune the work function (WF) of indium tin oxide (ITO), improving photovoltaic cell performance and device stability. In this study, we utilize a new class of boronic acid-based fluorine-terminated SAMs to modify ITO surfaces in planar perovskite solar cells. The SAM treatment demonstrates an increase of the WF of ITO, an enhancement of the short-circuit current, and a passivation of trap states at the ITO/[poly(3,4ethylenedioxylenethiophene):poly(styrenesulfonic acid)] interface. Device stability improves upon SAM modification, with efficiency decreasing only 20% after one month. Our work highlights a simple treatment route to achieve hysteresis-free, reproducible, stable, and highly efficient (16%) planar perovskite solar cells.