Enhancing the electron transfer and band potential tuning with long-term stability of ZnO based dye-sensitized solar cells by gallium and tellurium as dual-doping

Tellurium-based solar cells

In this article, we discuss about various Tellurium-based solar cells. Mainly this analysis focuses on the CdTe solar cells. The latest development in this area is incorporated in great detail. Te doping in various other solar cells is also discussed in the last part of the article.

Composites of Vanadium (III) Oxide (V2O3) Incorporating with Amorphous C as Pt-Free Counter Electrodes for Low-Cost and High-Performance Dye-Sensitized Solar Cells

To replace precious Pt-based counter electrodes (CEs) with a low-cost Pt-free catalyst of CEs is still a motivating hotspot to decrease the fabrication cost of dye-sensitized solar cells (DSSCs). Herein, four different V2O3@C composite catalysts were synthesized by pyrolysis of a precursor under N2 flow at 1100 °C and further served as catalytic materials of CEs for the encapsulation of DSSCs. The precursors of V2O3@C composites have been prepared via a sol-gel method using different proportions of V2O5 with soluble starch in a H2O2 solution. Power conversion efficiencies (PCEs) of 3.59, 4.79, 5.15, and 5.06% were obtained from different V2O3@C composites, with soluble starch-to-V2O5 mass ratios (S/V) of 1:2, 1:1, 2:1, and 4:1, respectively, as CEs to reduce iodide/triiodide in DSSCs. The improvement of electrode performance is due to the combined effects on the increased specific surface area and the enhanced conductivity of V2O3@C composite catalysts.

Hysteresis-Free Planar Perovskite Solar Cells with a Breakthrough Efficiency of 22% and Superior Operational Stability over 2000 h

Understanding the transport loss and the ways to improving optoelectronic properties of the charge transporting layers is critical to fabricate highly efficient, long-term stable, and hysteresis-free perovskite solar cells (PSCs). Herein, we report success in suppressing hysteresis and boosting the performance of operationally stable planar solar cells using a ruthenium (Ru) doped tin oxide (SnO₂) electron transport layer (ETL) and Zn-TFSI₂ doped spiro-OMeTAD hole transport layer (HTL). Apparently, the incorporation of Ru drastically shifts the Fermi level of SnO₂ ETL upward, which provides a facile route to tailor the ETL/perovskite band-offset to improve built-in electric fields of devices for improving V_OC and electron extraction simultaneously. Meanwhile, rapid injection of the photogenerated electrons from perovskite into ETL with reduced trap density is also observed when Ru doped SnO₂ is employed as ETL. On the other hand, the conception of Zn-TFSI₂ incorporation into HTL not only further boosts the photovoltaic performance but also prolongs the photostability of the devices. Consequently, a breakthrough efficiency of 22% (average 21.8%) with a J_SC of 24.6 mA cm^-2, V_OC of 1.15 V, and FF of 0.78 has been obtained in planar-type PSCs with a loss in efficiency of only ∼3% at maximum power point tracking over 2000 h.

Hydrogen sulphate-based ionic liquid-assisted electro-polymerization of PEDOT catalyst material for high-efficiency photoelectrochemical solar cells

This work reports the facile, one-step electro-polymerization synthesis of poly (3,4-ethylenedioxythiophene) (PEDOT) using a 1-ethyl-3-methylimidazolium hydrogen sulphate (EMIMHSO₄) ionic liquid (IL) and, for the first time its utilization as a counter electrode (CE) in dye-sensitized solar cells (DSSCs). Using the IL doped PEDOT as CE, we effectively improve the solar cell efficiency to as high as 8.52%, the highest efficiency reported in 150 mC/cm² charge capacity, an improvement of ~52% over the control device using the bare PEDOT CE (5.63%). Besides exhibiting good electrocatalytic stability, the highest efficiency reported for the PEDOT CE-based DSSCs using hydrogen sulphate [HSO₄]⁻ anion based ILs is also higher than platinum-(Pt)-based reference cells (7.87%). This outstanding performance is attributed to the enhanced charge mobility, reduced contact resistance, improved catalytic stability, smoother surface and well-adhesion. Our experimental analyses reveal that the [HSO₄]⁻ anion group of the IL bonds to the PEDOT, leading to higher electron mobility to balance the charge transport at the cathode, a better adhesion for high quality growth PEDOT CE on the substrates and superior catalytic stability. Consequently, the EMIMHSO₄-doped PEDOT can successfully act as an excellent alternative green catalyst material, replacing expensive Pt catalysts, to improve performance of DSSCs.