Fill factor in organic solar cells

Abstract

The fill factor (FF) is an important parameter that determines the power conversion efficiency of an organic solar cell. There are several factors that can significantly influence FF, and these factors interact with each other very intricately. Due to this reason, a deep understanding of FF is quite difficult. Based on the three fundamental elements in the solar cell equivalent circuit, namely series resistance, shunt resistance and diode, we reviews the research progress in understanding on FF in organic solar cells. Physics lying behind the often-observed undesirable S-shaped J-V curves is also summarized. This paper aims to give a brief and comprehensive summary on FF from a fundamental point of view.

Synthesis and characterization of D-A-A type regular terpolymers with narrowed band-gap and their application in high performance polymer solar cells

“…11,12 As for the active layer materials, many research efforts have been devoted to design and synthesis novel polymer donor materials with good solubility, broad absorption, optimized energy levels and high mobility. [13][14][15] The conjugated polymers with alternating electron-rich units (D) and electron-deficient segments (A), known as D-A structured polymers, [16][17][18] are one of the most efficient structures. Therefore, many electron-rich and electron-deficient building blocks have been used in the design and synthesis of novel D-A copolymer photovoltaic materials.…”

Understanding the Impact of Hierarchical Nanostructure in Ternary Organic Solar Cells

“…R s initially decreases as BDT‐3T‐CNCOO weight ratio decreases when the polymer is the dominant component; afterward, R s increases as BDT‐3T‐CNCOO weight ratio increases when the small molecule dominates (Figure 3e). The bulk resistance of the blend layer and the contact resistance are two of the main contributions to R s 35, 36. This result indicates that the incorporated small molecule affects the charge transport property in the blend layer and the contact property between an active layer and an electrode.…”

Enhanced lifetime of organic photovoltaic diodes utilizing a ternary blend including an insulating polymer

“…The ternary devices do not show a significant change in R S while a noticeable increase was observed in binary devices at both humidity levels, as shown in Table SI2 (c and d). However, the increase in apparent series resistance may also be due to an increase in the contact resistance between the electrodes and the active materials [25] due to the diffusion of oxygen and electrode materials into the active layer [3] Ultraviolet-visible absorption spectra of ternary and binary thin films before and after aging were measured and are shown in Figure SI hours [10]. Hence, the formation of oxidized species in the active layer is slow here; we attribute this to devices being stored in the dark between tests, which in turn will mitigate photo-oxidation [10,26].…”