Eco-Friendly Polymer Solar Cells: Advances in Green-Solvent Processing and Material Design

Abstract

Despite the recent breakthroughs of polymer solar cells (PSCs) exhibiting a power conversion efficiency of over 17%, toxic and hazardous organic solvents such as chloroform and chlorobenzene are still commonly used in their fabrication, which impedes the practical application of PSCs. Thus, the development of eco-friendly processing methods suitable for industrial-scale production is now considered an imperative research focus. This Review provides a roadmap for the design of efficient photoactive materials that are compatible with non-halogenated green solvents (e.g., xylenes, toluene, and tetrahydrofuran). We summarize the recent development of green processing solvents and the processing methods to match with the efficient photoactive materials used in non-fullerene solar cells. We further review progress in the use of more eco-friendly solvents (i.e., water or alcohol) for achieving truly sustainable and ecofriendly PSC fabrication. For example, the concept of water-or alcohol-dispersed nanoparticles made of conjugated materials is introduced. Also, recent important progress and strategies to develop water/alcohol-soluble photoactive materials that completely eliminate the use of conventional toxic solvents are discussed. Finally, we provide our perspectives on the challenges facing the current green processing methods and materials, such as large-area coating techniques and long-term stability. We believe this Review will inform the development of PSCs that are truly clean and renewable energy sources.

Green Nanocomposites for Energy Storage

“…The ZnS nanoparticles were also used in solar cells as sustainable nanofiller. Thus, the solar cell devices have also incorporated green nanocomposites [99][100][101]. Ghosh et al [102] formed poly(vinylidenefluoride-co-hexafluoropropylene) and platinum nanoparticles-based green materials for solar cells.…”

New Dithiazole Side Chain Benzodithiophene Containing D–A Copolymers for Highly Efficient Nonfullerene Solar Cells

“…Bulk heterojunction (BHJ) active layer‐based polymer solar cells (PSCs) have gained significant interest due to their advantages such as light‐weight, flexibility, low cost, and scalable large‐scale manufacturing. [ 1–6 ] Additionally, recent initiation of nonfullerene small molecule acceptors (NFSMAs) [ 7–15 ] has resulted to significant improvement in the power conversion efficiency (PCE) of the single BHJ PSCs in the range of 17–18% [ 16–21 ] since NFSMAs overcome the several limitations of the fullerene‐based acceptors, such as poor light absorption, less tunability of optical and electrochemical properties, and large phase separations. In order to fabricate the high performance NFSMA‐based PSCs, there should be the balance optimization between the polymer donors and NFSMAs in the BHJ active layers, [ 22,23 ] since the overall photovoltaic parameters are predominantly governed by the intimate interplays between the two materials employed.…”

High‐Performance Fullerene Free Polymer Solar Cells Based on New Thiazole ‐Functionalized Benzo[1,2‐b:4,5‐b′]dithiophene D‐A Copolymer Donors

“…Polymer solar cells (PSCs) based on bulk heterojunction (BHJ) active layer have established considerable attention from researchers around the globe owing to their advantages such as lightweight, semitransparency and low-cost construction, which is beneficial for their commercialization. [1][2][3][4][5][6][7][8] In general, the BHJ film consists of a blend of electron donor material (either conjugated polymer or small molecule) and electronaccepting material, i. e., fullerene derivative or non-fullerene small molecule acceptor (NFSMA). With the emergence of NFSMAs, [9][10][11][12][13][14] development of new conjugated copolymer donors, optimization of BHJ active layer and device configuration, the power conversion efficiency (PCE) has been increased up to 17-18 %.…”

“…Polymer solar cells (PSCs) based on bulk heterojunction (BHJ) active layer have established considerable attention from researchers around the globe owing to their advantages such as lightweight, semitransparency and low‐cost construction, which is beneficial for their commercialization [1–8] . In general, the BHJ film consists of a blend of electron donor material (either conjugated polymer or small molecule) and electron‐accepting material, i. e., fullerene derivative or non‐fullerene small molecule acceptor (NFSMA).…”