Can Polymer Solar Cells Open the Path to Sustainable and Efficient Photovoltaic Windows Fabrication?

Abstract

Sunlight is among the most abundant energy sources available on our planet. Finding adequate solutions to properly and efficiently harvest it is of major importance to potentially solve the global energy crisis. Polymer solar cells have been introduced in the late 20th century as low‐cost and easily processed alternative to the state‐of‐the‐art silicon photovoltaics. Their power conversion efficiencies, which were initially rather low, are constantly improving and now reach values close to 15 %. As their optical properties can be easily tuned, designing active layer which absorb homogeneously throughout the visible spectrum is relatively simple. These peculiar characteristics enable the possibility to fabricate visibly transparent solar cells with high color rendering indices which can be employed as photovoltaic windows. After reviewing some of the most successful examples of polymer solar cell‐based transparent photovoltaic window fabrication, I will discuss the possibility to produce these devices in a sustainable and/or eco‐friendly manner while maintaining their performances.

Photochromic organic solar cells based on diarylethenes

“…Organic bulk heterojunction (BHJ) solar cells have received considerable attention in recent years as they promise to combine high performance and device exibility with low cost. [1][2][3] However, in terms of large scale photovoltaic energy production, alternative technologies are better suited at present. 4,5 It is therefore also of interest to explore alternative application areas for organic solar cells to exploit the unique properties of organic molecules.…”

Water-Processed Organic Solar Cells with Open-Circuit Voltages Exceeding 1.3V

“…Over the past decades, several solution-processable photovoltaic technologies have been introduced to replace the state-of-the-art silicon solar cells, which require a large energy input during their fabrication [1][2][3][4]. Among the alternative low carbon footprint solutions, organic solar cells (OSCs) exhibit a strong potential for facile integration into a variety of flexible and semitransparent technologies [1,[5][6][7][8]. However, during their conventional active layers processing, an enormous amount of chlorinated solvent waste is generated, which is dangerous for the human health and the environment [5,9].…”

“…Among the alternative low carbon footprint solutions, organic solar cells (OSCs) exhibit a strong potential for facile integration into a variety of flexible and semitransparent technologies [1,[5][6][7][8]. However, during their conventional active layers processing, an enormous amount of chlorinated solvent waste is generated, which is dangerous for the human health and the environment [5,9]. To mitigate the negative impact of OSC fabrication on the environment, several strategies have been investigated recently, which include the use of "greener" solvents such as limonene or nonhalogenated benzene derivatives [10][11][12][13], the synthesis of new organic semiconductors that are readily soluble in polar solvents [14], the introduction of water-based organic semiconductor inks [15][16][17], and the development of new coating processes to reduce wastes [18,19].…”

Eco-Friendly Push-Coated Polymer Solar Cells with No Active Material Wastes Yield Power Conversion Efficiencies over 5.5%

“…As the PSC active layers have excellent film formation properties, they exhibit a great potential for facile high volume processing. Although the general trend in PSC-related laboratory research is to deposit the active layers by spin-coating, several alternative processes such as blade-coating, slot die-coating, or spraying have been explored to prepare for large-scale production and commercialization of emerging PSC-based technologies like photovoltaic windows. − In terms of practical implementation and initial investment, removing the necessity for a nitrogen-filled glovebox during device fabrication has become a priority and thus stable materials that can be processed in air have been receiving increasing interest . Poly­(2,7-carbazole- alt -dithienylbenzothiadiazole) (PCDTBT) is a low band gap copolymer with a fairly simple molecular design which has been gradually replacing poly­(3-hexylthiophene-2,5-diyl) (P3HT) as the reference electron donor in the PSC field. ,− When combined with [6,6]-phenyl-C 71 -butyric acid methyl ester (PC 71 BM) in PSC active layers, PCDTBT exhibits excellent air stability and typically produces PCEs over 5%. ,,, Despite its simple molecular design, the cost of PCDTBT can be 3 to 5 times higher than that of P3HT.…”