The development of indoor photovoltaic devices for powering Internet of Things (IoT) sensors requires low-cost and sustainable components, making dye-sensitized solar cells (DSSCs) an ideal candidate for artificial light harvesting. The counter electrode plays a critical role in transferring electrons and catalyzing the reduction in the redox electrolyte. However, the traditional use of expensive and scarce platinum (Pt) limits the cost-effective, large-scale commercialization of these devices. While carbon-based materials offer a highly porous, conductive, and abundant alternative, commercial carbon pastes frequently require energy-intensive high-temperature sintering. In this study, we propose a sustainable, low-temperature, and screen-printable carbon composite counter electrode (LoT-HPC) using bio-derived hydroxypropyl cellulose (HPC) as a highly effective binder. Rheological characterizations confirm that the formulated LoT-HPC ink possesses an ideal shear-thinning profile and rapid structural recovery, ensuring excellent printability and film homogeneity. By comparing the custom LoT-HPC composite against a commercial high-temperature screen-printed graphite paste (HT-Elco) and a standard sputtered Pt-FTO electrode, we demonstrate the structural and electrocatalytic advantages of this material. When integrated into full DSSC devices and evaluated under low indoor illumination (1000 lux), the LoT-HPC cell delivers a power conversion efficiency (PCE) of 14.8% and a high short-circuit current density of 103.9 µA cm⁻². Furthermore, the custom device demonstrated exceptional operational stability, retaining 98.6% of its initial efficiency (from 14.8% to 14.6%) after 200 h of continuous light-soaking and J-V cycling under 1000 lux. Ultimately, the successful implementation of the HPC binder enables the low-temperature fabrication of sustainable carbon counter electrodes without the need for energy-intensive thermal treatments, presenting a highly scalable pathway for indoor DSSC manufacturing.

Laser‐induced graphene (LIG) has emerged as a highly promising material for energy storage devices due to its excellent electrical conductivity, high specific surface area, and compatibility with flexible substrates. Despite these advantages, one of the main challenges in implementing LIG‐based electrodes is achieving a stable and efficient electrical connection with metallic current collectors without compromising the intrinsic properties of the material. In this study, we investigate a combination of physical approaches to establish a reliable and robust electrical bond between LIG and metal current collectors while avoiding chemical treatments, conductive adhesives, or binders. Electrode fabrication is performed using physical vapor deposition (PVD) and laser processing techniques, which provide precise control over both metallic layer deposition and LIG formation. These methods enable straightforward customization of electrode architectures for applications, including symmetric and hybrid energy storage devices. Furthermore, fast and selective laser treatments are adopted to enhance the mechanical integrity and long‐term stability of the electrode interfaces. Our results demonstrate a contact resistance as low as 1.3 Ω at the LIG‐gold interface without the use of binders or additional conductive agents. The proposed fabrication strategy improves electrical performance while simplifying the overall manufacturing process. By minimizing complex chemical procedures, it enables scalability.

This work explores an innovative approach to convert CO ₂ into a valuable energy resource using ionic liquid (IL)–based electrochemical systems. The employed ionic liquid, [DBUH][Im], combines the strong CO ₂ affinity of imidazole with the high basicity of DBU, promoting selective carbamate formation while suppressing parasitic reactions. CO ₂ chemisorption induces ion rearrangement at the electrode–electrolyte interface, generating a measurable open‐circuit voltage shift. However, the high viscosity of the pristine IL significantly restricts ionic mobility, especially after CO ₂ absorption. Dilution with propylene carbonate improves conductivity and enhances electrochemical performance. A multiparametric study was conducted under realistic working conditions, evaluating gas flow rate influence, CO ₂ /N ₂ selectivity, operating temperature, and long‐term stability. Moreover, the introduction of a supporting‐salt further improved ionic conductivity, interfacial properties, and pore accessibility, leading to higher capacitance and harvested power. Overall, these results highlight the potential of tailored IL‐based electrolytes for integrated CO ₂ capture and energy conversion technologies.