Computational predictions of adaptive aromaticity for the design of singlet fission materials

Singlet fission has attracted extensive attention from experimentalists and theoreticians due to its ability to improve photovoltaic conversion efficiency. Still, designing singlet fission materials remains challenging. In this work, we...

Novel Anthracene HTM Containing TIPs for Perovskite Solar Cells

Recently, perovskite solar cells have been in the spotlight due to several of their advantages. Among the components of PSCs, hole transporting materials (HTMs) re the most important factors for achieving high performance and a stable device. Here, we introduce a new D–π–D type hole transporting material incorporating Tips-anthracene as a π–conjugation part and dimethoxy-triphenylamine as a donor part (which can be easily synthesized using commercially available materials). Through the measurement of various optical properties, the new HTM not only has an appropriate energy level but also has excellent hole transport capability. The device with PEH-16 has a photovoltaic conversion efficiency of 17.1% under standard one sun illumination with negligible hysteresis, which can be compared to a device using Spiro_OMeTAD under the same conditions. Ambient stability for 1200 h shown that 98% of PEH-16 device from the initial PCE was retained, indicating that the devices had good long-term stability.

Antireflection Improvement and Junction Quality Optimization of Si/PEDOT:PSS Solar Cell with the Introduction of Dopamine@Graphene

Si/PEDOT: PSS solar cell is an optional photovoltaic device owing to its promising high photovoltaic conversion efficiency (PCE) and economic manufacture process. In this work, dopamine@graphene was firstly introduced between the silicon substrate and PEDOT:PSS film for Si/PEDOT: PSS solar cell. The dopamine@graphene was proved to be effective in improving the PCE, and the influence of mechanical properties of dopamine@graphene on solar cell performance was revealed. When dopamine@graphene was incorporated into the cell preparation, the antireflection ability of the cell was enhanced within the wavelength range of 300~450 and 650~1100 nm. The enhanced antireflection ability would benefit amount of the photon-generated carriers. The electrochemical impedance spectra test revealed that the introduction of dopamine@graphene could facilitate the separation of carriers and improve the junction quality. Thus, the short-circuit current density and fill factor were both promoted, which led to the improved PCE. Meanwhile, the influence of graphene concentration on device performances was also investigated. The photovoltaic conversion efficiency would be promoted from 11.06% to 13.15% when dopamine@graphene solution with concentration 1.5 mg/mL was applied. The achievements of this study showed that the dopamine@graphene composites could be an useful materials for high-performance Si/PEDOT:PSS solar cells.

Study of How Photoelectrodes Modified by TiO2/Ag Nanofibers in Various Structures Enhance the Efficiency of Dye-Sensitized Solar Cells under Low Illumination

Dye-sensitized solar cells (DSSCs) are low-cost solar cells belonging to the thin-film photovoltaic cell type. In this study, we studied the photovoltaic performances of DSSCs based on titanium dioxide (TiO2) nanofibers (NFs) containing silver (Ag) nanoparticles (NPs) under low illumination. We used the sol-gel method with the electrospinning technique to prepare the TiO2 NFs containing Ag NPs. Herein, we used two ways to add TiO2/Ag NFs to modify the photoelectrode successfully and enhance the performance of DSSCs. One way was that the TiO2/Ag NFs were mixed with pristine TiO2; the other way was that the TiO2/Ag NFs were seeded beside the TiO2 colloid layer as an additional layer on the photoelectrode of the DSSC. According to this experiment, the photovoltaic conversion efficiency of the DSSC which had TiO2/Ag NF seeded as an additional layer on the photoelectrode (5.13%) was increased by 28% compared to the DSSC without the photoelectrode modification (3.99%). This was due to the suppression of electron recombination and the more effective utilization of the light radiation by adding the TiO2/Ag NFs. Because of the good conductivity of Ag, the electrons were quickly transported and electron recombination was reduced. In addition, the photovoltaic conversion efficiency of the DSSC which had TiO2/Ag NF seeded as an additional layer on the photoelectrode increased from 5.13% to 6.23% during the decrease in illumination from 100 mW/cm2 to 30 mW/cm2; however, its photovoltaic conversion efficiency decreased to 5.31% when the illumination was lowered to 10 mW/cm2.

Thermocells for Hybrid Photovoltaic/Thermal Systems

The photovoltaic conversion efficiency of solar cells is highly temperature dependent and decreases with increasing temperature. Therefore, the thermal management of solar cells is crucial for the efficient utilization of solar energy. We fabricate a hybrid photovoltaic/thermocell (PV/T) module by integrating a thermocell directly into the back of a solar panel and explore the feasibility of the module for its practical implementation. The proposed PV/T hybrid not only performs the cooling of the solar cells but also produces an additional power output by converting the heat stored in the solar cell into useful electric energy through the thermocell. Under illumination with an air mass of 1.5 G, the conversion efficiency of the solar cell can improve from 13.2% to 15% by cooling the solar cell from 61 °C to 34 °C and simultaneously obtaining an additional power of 3.53 μW/cm2 from the thermocell. The advantages of the PV/T module presented in this work, such as the additional power generation from the thermocell as well as the simultaneous cooling of the solar cells and its convenient installation, can lead to the module’s importance in practical and large-scale deployment.

Modeling and optimization of n-ZnO/p-Si heterojunction using 2-dimensional numerical simulation

In this work, n-ZnO/p-Si heterojunction was investigated using two-dimensional numerical simulation. The effect of Zinc Oxide thickness, carrier concentration in Zinc Oxide layer, minority carrier lifetime of bulk Silicon and the interface states density on electrical properties were studied in dark and under illumination conditions. This study aimed to optimize these parameters in order to obtain n-ZnO/p-Si solar cell with high conversion efficiency and low cost. The simulation was carried out by Atlas silvaco software. As results, a very low saturation current Is, low series resistance Rs, an ideality factor n between 1 and 1.5 were obtained for optimal charge carrier concentrations in the range [5 × 1019–5 × 1021 cm−3] and a thickness of Zinc Oxide between 0.6 and 2 µm. Moreover, a photovoltaic conversion efficiency of 24.75% was achieved without interfacial defect, which decreases to 5.49% for an interface defect density of 5 × 1014 cm−2.