Nanoenergy Adv., Volume 4, Issue 3 (September 2024) – 2 articles

In this study, we explored the potential of exfoliated transition metal dichalcogenides (TMDs) as innovative spray-coated hole transport layers (HTLs) in organic photovoltaics (OPVs), addressing the need for efficient and stable materials in solar cell technology. This research was motivated by the need for alternative HTLs that can offer enhanced performance under varying lighting conditions, particularly in indoor environments. Employing UV-visible absorption and Raman spectroscopy, we characterized the optical properties of MoS₂, MoSe₂, WS₂, and WSe₂, confirming their distinct excitonic transitions and direct bandgap features. The nanocrystalline nature of these TMDs, revealed through XRD patterns and crystallite size estimation using the Scherrer method, significantly contributes to their enhanced physical properties and operational efficiency as HTLs in OPVs. These TMDs were then integrated into OPV devices and evaluated under standard solar and indoor lighting conditions, to assess their effectiveness as HTLs. The results demonstrated that MoS₂, in particular, displayed remarkable performance, rivalling traditional HTL materials like MoO₃. It maintained high power conversion efficiency across a spectrum of light intensities, illustrating its versatility for both outdoor and indoor applications. Additionally, MoS₂ showed superior stability over extended periods, suggesting its potential for long-term usage in OPVs. This study contributes significantly to the field of photovoltaic materials, presenting TMDs, especially MoS₂, as promising candidates for efficient and stable OPVs in diverse lighting conditions, thereby broadening the scope of solar cell applications. Full article

Engineering polymers stand out as the predominant dielectric materials in triboelectric nanogenerators (TENGs), primarily owing to their robust triboelectric effect and widespread availability. However, growing environmental concerns surrounding these polymers have prompted a notable shift towards exploring alternative eco-friendly materials, with cellulose materials emerging as compelling contenders over the past few years. Cellulose, derived from various sources and presented in diverse forms and structures, has found utility as triboelectric materials. In contrast to many engineering polymers known for their chemical stability, cellulose materials exhibit heightened chemical activities. This characteristic provides a unique opportunity to delve into fundamental questions in TENGs by manipulating the physical and chemical properties of cellulose materials. This concise critical review aims to thoroughly examine the applications of cellulose materials while shedding light on the opportunities presented by these versatile materials. Full article