Emerging Trends in Electron Transport Layer Development for Stable and Efficient Perovskite Solar Cells

Perovskite solar cells (PSCs) stand at the forefront of photovoltaic research, with current efficiencies surpassing 26.1%. This review critically examines the role of electron transport materials (ETMs) in enhancing the performance and longevity of PSCs. It presents an integrated overview of recent advancements in ETMs, like TiO2, ZnO, SnO2, fullerenes, non-fullerene polymers, and small molecules. Critical challenges are regulated grain structure, defect passivation techniques, energy level alignment, and interfacial engineering. Furthermore, the review highlights innovative materials that promise to redefine charge transport in PSCs. A detailed comparison of state-of-the-art ETMs elucidates their effectiveness in different perovskite systems. This review endeavors to inform the strategic enhancement and development of n-type electron transport layers (ETLs), delineating a pathway toward the realization of PSCs with superior efficiency and stability for potential commercial deployment.

An analysis of the dye-sensitized solar cells fabricated with the dyes extracted from the leaves and flowers of Amaranthus cruentus

Dye-sensitized solar cells (DSSCs) were devised with the sensitizers prepared from the leaves and flowers of Amaranthus cruentus. Fresh and dried leaves were employed for extracting the dye sensitizers. Acetone, ethanol, and deionized water were used as solvents for the extraction process. A sum of nine dyes was prepared. For all the extracted dyes, spectroscopic studies (UV-visible & FTIR) were performed to ensure that the dyes are suitable to be used as sensitizers for DSSC. XRD and SEM were recorded for the TiO₂ paste used. Nine DSSCs were fabricated with the extracted dyes as sensitizers, TiO₂ as semiconductor oxide, I^-/I^3- as electrolyte, and graphene-coated FTO as counter electrode. J-V characterization study was done for each cell showed that the cell with dye taken from the fresh leaves using acetone exhibited the highest efficiency of 0.816%. It was noted that these cells recorded higher efficiency than the previously reported works with dyes taken from Amaranthus red.

Charge transport materials for mesoscopic perovskite solar cells

An overview on recent advances in the fundamental understanding of how interfaces of mesoscopic perovskite solar cells (mp-PSCs) with different architectures, upon incorporating various charge transport layers, influence their performance.

Improved efficient perovskite solar cells based on Ta-doped TiO2 nanorod arrays

Organometal halide perovskite solar cells (PSCs) are nowadays regarded as a rising star in photovoltaics. In particular, PSCs incorporating oriented TiO₂ nanorod (NR) arrays as the electron transport layer (ETL) have attracted significant attention owing to TiO₂ NR's superior electron transport abilities and its potential in long-term stable PSCs. In addition to improve the electron-transport ability of TiO₂ NRs, the tuning of the band alignments between the TiO₂ NR array and the perovskite layer is also crucial for achieving efficient solar cells. This work describes a facile, one-step, solvothermal method for the preparation of tantalum (Ta) doped TiO₂ NR arrays for efficient PSCs. It is shown that the trace doping with Ta tunes the electronic structure of TiO₂ NRs by a synergistic effect involving the lower 5d orbitals of the doped Ta⁵⁺ ions and the reduced oxygen vacancies. The synergistic tuning of the electronic structure improves the band alignment at the TiO₂ NR/perovskite interface and boosts the short-circuit current and the fill factor. By using the optimized doped TiO₂ NR array as the ETL, a record efficiency of 19.11% was achieved, which is the highest among one-dimensional-array based PSCs.