Bio-Inspired Graphitic Carbon-Based Large-Area (10 × 10 cm2) Perovskite Solar Cells: Stability Assessments under Indoor, Outdoor, and Water-Soaked Conditions.

In the emerging photovoltaic (PV) technologies, the golden triangle rule includes higher efficiency, longevity (or stability), and low cost, which are the foremost criteria for the root of commercial feasibility. Accordingly, a unique low-cost, ecofriendly, all-solution-processed, "bio-inspired" graphitic carbon (extracted from the most invasive plant species of Eichhornia crassipes: listed as one of the 100 most dangerous species by the International Union for Conservation of Nature) and a mixed halide perovskite interface-engineered, unique single-cell large-scale (10 × 10 sq.cm with an active area of 88 cm2) carbon-based perovskite solar cell (C-PSC) are demonstrated for the first time, delivering a maximum PCE of 6.32%. Notable performance was observed under low light performance for the interface-engineered champion device fabricated using the layer-to-layer approach, which, even when tested under fluorescent room light condition (at 200 lux of about ∼0.1 SUN illumination), exhibited a significant PCE. In terms of addressing the stability issues in the fabricated PSC devices, the present work has adopted a two-step strategy: the instability toward the extrinsic factors is addressed by encapsulation, and the subsequent intrinsic instability issue is also addressed through interfacial engineering. Surprisingly, when tested under various stability conditions (STC) such as ambient air, light (continuous 1 SUN, under room light illumination (0.1 SUN) and direct sunlight), severe damp up to a depth of ∼25 mm water (cold (∼15 °C) and hot (∼65 °C)), acidic pH (∼5), and alkaline pH (∼11)) conditions, the fabricated large-scale carbon-based perovskite solar cells (C-LSPSCs) retained unexpected long-term stability in their performance for over 50 days. As to appraise the performance superiority of the fabricated C-LSPSC devices under various aforesaid testing conditions, a working model of a mini-fan has been practically powered and demonstrated.

Comparison of three different structures of zeolites prepared by template-free hydrothermal method and its CO2 adsorption properties.

In this study, zeolite sodalite SOD (50NaO2:Al2O3:5SiO2), zeolite LTA (2NaO2:Al2O3:1.926SiO2) and zeolite FAU (16NaO2:Al2O3:4SiO2) of different structures were synthesized successfully through simple conventional hydrothermal crystallization technique without using any template agent. Morphological analysis of three different types of zeolites revealed that the samples exhibit three different shapes such as the "Raspberry-like", "Dice" cube like and "Octahedral" shaped morphology respectively. The thermal stability was found to be about 4.8%, 14.6% and 20.5% for the synthesized zeolites SOD, LTA and FAU respectively. From the N2 adsorption-desorption studies, it was observed that adsorption types IV and I correspond to the synthesized samples. CO2 adsorption by the synthesized zeolite SOD, LTA and FAU were examined in the pressure range from 0 to 101.325 kPa at a constant temperature of 297.15 K. The highest adsorption capacity of 3.7 mmol/g was obtained for zeolite FAU. The synthesized zeolite was studied using a nonlinear regression curve fit to determine the adsorption isotherm model using Langmuir and Freundlich isotherm model. It has been found that the synthesized zeolites have a large electric field gradient due to which they can strongly adsorb quadrupole of CO2 molecules.

TiO2/AgO composites by one step photo reduction technique as electron transport layers (ETL) for dye-sensitized solar cells.

Dye-sensitized solar cell's electron transport layer is responsible for transporting photo-generated electrons to the outer circuit. Utilizing localized surface plasmon resonance (SPR), light absorption could be enhanced to a greater degree, which can drive dye molecules to excited state more effectively than far-field light. In this work, TiO2 nanoparticles were prepared by solvothermal method, and Ag nanoparticles were decorated over TiO2 surface through photodeposition method. XRD data of the TiO2 sample exhibits anatase phase and in the Ag nanoparticle decorated TiO2 sample, peaks corresponding to (111) planes of Ag was observed. UV-Vis absorption analysis of the TiO2 and Ag decorated TiO2 samples showed absorption in the UV region for the TiO2, and the SPR effect was detected for the Ag deposited TiO2 samples. Ag nanoparticles decorated over TiO2 was observed to be spherical in shape through the images from transmission electron microscope. Presence of both Ag and AgO in the prepared sample was revealed through the data from X-ray photoelectron spectroscopy. The prepared material was used as photoanodes in the construction of the DSSCs, and their performance was evaluated.

Perovskite Solar Cells: A Porous Graphitic Carbon based Hole Transporter/Counter Electrode Material Extracted from an Invasive Plant Species Eichhornia Crassipes.

Perovskite solar cells (PSCs) composed of organic polymer-based hole-transporting materials (HTMs) are considered to be an important strategy in improving the device performance, to compete with conventional solar cells. Yet the use of such expensive and unstable HTMs, together with hygroscopic perovskite structure remains a concern - an arguable aspect for the prospect of onsite photovoltaic (PV) application. Herein, we have demonstrated the sustainable fabrication of efficient and air-stable PSCs composed of an invasive plant (Eichhornia crassipes) extracted porous graphitic carbon (EC-GC) which plays a dual role as HTM/counter electrode. The changes in annealing temperature (~450 °C, ~850 °C and ~1000 °C) while extracting the EC-GC, made a significant impact on the degree of graphitization - a remarkable criterion in determining the device performance. Hence, the fabricated champion device-1c: Glass/FTO/c-TiO2/mp-TiO2/CH3NH3PbI3-xClx/EC-GC10@CH3NH3PbI3-x Clx/EC-GC10) exhibited a PCE of 8.52%. Surprisingly, the introduced EC-GC10 encapsulated perovskite interfacial layer at the perovskite/HTM interface helps in overcoming the moisture degradation of the hygroscopic perovskite layer in which the same champion device-1c evinced better air stability retaining its efficiency ~94.40% for 1000 hours. We believe that this present work on invasive plant extracted carbon playing a dual role, together as an interfacial layer may pave the way towards a reliable perovskite photovoltaic device at low-cost.