Organic Photovoltaics

Abstract

Organic photovoltaics (OPV) describes a group of technologies wherein the active layer of a solar cell is composed of hydrocarbon-based organic materials [1][2][3]. OPV occupies a special niche among solar energy technologies in that it could potentially satisfy the growing energy needs of the world with a product that is sustainable, elementally abundant, and cheaply manufactured. OPV cells have recently seen a dramatic uptick in reported efficiencies, with power conversion efficiencies reaching ≈11 %, as shown in Fig. 6.1 [4,5]. These increases in power conversion efficiency have largely been driven by the development and discovery of new OPV active layer materials and new ways to process them. The technology has gained significant commercial attention over the past decade, as its unique attributes merit consideration for a place in the landscape of distributed energy generation devices [6]. Some of OPV advantages include a flexible form factor and facile processing, either from fluids or from vacuum deposition.At least two different device designs are often regarded as OPV technologies. The first is based on a solid-state OPV cell, having typically two organic semiconductors in a bilayer or distributed heterojunction arrangement. The second type, which will not be addressed in this chapter, is more typically called a dye-sensitized solar cell (DSSC) [7], which relies on a mesoporous electron conductor that is typically inorganic, a sensitizing dye, and an ion-conducting redox electrolyte. Unlike organic heterojunctions, the DSSC contains liquid and thus faces challenges in packaging and limited flexibility.The first report of a solid-state OPV cell was as early as 1959, when a photovoltaic effect in ≈10-μm-thick anthracene crystals was reported [8].

Molecular Ion Formation by Photoinduced Electron Transfer at the Tetracyanoquinodimethane/Au(111) Interface

“…Photoinduced processes are exploited in light harvesting and switching, data storage, or sensor technologies. − In recent years, in particular, organic semiconducting materials have achieved much attention due to the rise in energy conversion efficiencies of organic solar cells. − Besides a strong application-oriented research and development of organic solar cells or light-emitting diodes, a detailed analysis and characterization of the elementary processes in optically induced reactions is needed to optimize the performance of the optoelectronic devices. ,− Molecular ordering, contamination or doping, and varying ambient conditions influence photosensitive reactions. Furthermore, illumination conditions such as photon energy and photon dose have an influence that in combination makes the studies on photoinduced processes in organic materials to an elaborate and challenging research field. − However, only controlled experimental conditions and well-defined samples enable the investigation of the fundamental photophysical and -chemical processes, such as, for instance, photoinduced charge transfer at interfaces.…”

Beyond Fullerenes: Indacenodithiophene-Based Organic Charge-Transport Layer toward Upscaling of Low-Cost Perovskite Solar Cells

“…As there was no annealing process after the deposition of ETL, it is likely that these particles are PCBM crystals because PCBM self-organizes into micro- or nanocrystalline structure upon slow solvent evaporation . The PCBM-only films are seldom reported, but PCBM in blends with conjugated polymers are widely studied because it is the most commonly used acceptor in bulk heterojunction organic solar cells . Several studies have revealed that the size of PCBM aggregates/agglomerates increases over time in blends in which PCBM is in mixture with a high-molecular-weight conjugated polymer. − In PeSCs in which PCBM exists as a pure film, the aggregation tendency is likely to be higher, which may prove a hindrance to stability.…”

Electronic Spectra of C60 Films Using Screened Range Separated Hybrid Functionals

“…Organic semiconducting materials containing C 60 have been a subject of extensive study, primarily in the context of optoelectronics applications such as organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), organic photovoltatics (OPV), perovskite solar cells, and sensors . The optical absorption spectra of C 60 have been experimentally measured in the gas phase, − in solution, in noble gas matrices, − and in thin film phase .…”