• Energy Research

The rapid development of perovskite solar cells (PSCs) over the past decade makes it the most promising next generation photovoltaic technology. Splendid progress in efficiency and stability has been demonstrated in laboratory level, while endeavours are extremely required to enable successful transfer of the printable PSC technology to industry scale toward commercialization. In this work, recent progresses on upscaling of PSCs are systematically reviewed. Starting with the traditional PSC structure, we have analyzed the specially designed configuration for perovskite solar modules (PSMs). The comprehensive overview and assessment are provided for the technologies engineering in large-scale preparation, including both solution processing and vapor-phase deposition methods. Considering the promoting effect of material engineering to scale up PSMs, the application of additive engineering, solvent engineering and interface engineering on the stability and efficiency of PSMs is systematacially discussed. Moreover, the effect of current packaging technology of PSMs on device lifetime and environmental friendliness is emphasized. At last, we propose the prospects and challenges of PSMs commercialization in the future to meet the requirements for next generation photovoltaic industry.

Morphology is crucial to determining the photovoltaic performance of organic solar cells (OSCs). However, manipulating morphology involving only small-molecule donors and acceptors is extremely challenging. Herein, a simple terminal alkyl chain engineering process is introduced to fine-tune the morphology towards high-performance all-small-molecule (ASM) OSCs. We successfully chose a chlorinated two-dimension benzo[1,2-b:4,5-b′]dithiophene (BDT) central unit and two isomeric alkyl cyanoacetate as the end-capped moieties to conveniently synthesize two isomeric small-molecule donors, namely, BT-RO-Cl and BT-REH-Cl, each bearing linear n-octyl (O) as the terminal alkyl chain and another branched 2-ethylhexyl (EH) as the terminal alkyl chain. The terminal alkyl chain engineering process provided BT-RO-Cl with 13.35% efficiency and BT-REH-Cl with 13.90% efficiency ASM OSCs, both with Y6 as the electron acceptor. The successful performance resulted from uniform phase separation and the favorable combination of face-on and edge-on molecular stacking of blended small-molecule donors and acceptors, which formed a fluent 3D transport channel and thus delivered high and balanced carrier mobilities. These findings demonstrate that alkyl chain engineering can finely control the morphology of ASM OSCs, and provides an alternative for the optimal design of small-molecule materials towards high-performance ASM OSCs.

Over the past decade, perovskite photovoltaics have approached other currently available technologies and proven to be the most prospective type of solar cells. Although the many‐sided research in this very active field has generated consistent results with regard to their undisputed consistently increasing power conversion efficiency, it also produced several rather contradictory opinions. Among other important details, debate surrounding their proneness to surface degradation and poor mechanical robustness, as well as the environmental footprint of this materials class, remains a moot point. The application of ionic liquids appears as one of the potential remedies to some of these challenges due to their high conductivity, the opportunities for chemical “tuning” of the structure, and relatively lower environmental footprint. This article provides an overview, classification, and applications of ionic liquids in perovskite solar cells. We summarize the use and role of ionic liquids as versatile additives, solvents, and modifiers in perovskite precursor solution, in charge transport layer, and in interfacial and stability engineering. Finally, challenges and the future prospects for the design and/or selection of ionic liquids with a specific profile that meets the requirements for next‐generation highly efficient and stable perovskite solar cells are proposed.

Solution‐processed perovskite solar cells (PSCs) are widely and dramatically developed with certificated record efficiency up to 25.7%, which have been regarded as the most promising candidates for next‐generation photovoltaic devices. However, the current decent devices are dominantly fabricated based on traditional toxic organic solvents such as N,N‐dimethylformamide and dimethyl sulfoxide, which inevitably leads to environmental damage and potential safety accidents. As green and nontoxic molten salts at room temperature, ionic liquids (ILs) as promising alternatives for traditional toxic organic solvents have attracted intensive research interest worldwide in the field of perovskite photovoltaics with encouraging development. Herein, especially concentrating on ILs solvent engineering rather than additive or post‐treatment, discussion and summarization upon the recent progress on perovskite photovoltaics including both 3D and 2D‐based PSCs is systematically carried out. An in‐depth understanding regarding the interactions between IL molecules and perovskite precursor materials is thoroughly explored and summarized. Moreover, the detailed influence of ILs as solvent(s) on the aspects of perovskite material crystallization regulation, surface defect passivation, and performance improvement of resultant device is comprehensively overviewed and discussed. Finally, prospects of the application of ILs in the PSCs through solvent engineering are provided for further developments.

A nonfullerene acceptor, isoIDITC, capable of exhibiting fibril-like morphology, is utilized as a third component in organic photovoltaic devices. A power conversion efficiency of 19% is achieved in ternary PM6:BTP-eC9:isoIDITC bulk-heterojunction devices.

AbstractOrganic solar cells (OSCs) have emerged as a promising solution for sustainable energy production, offering advantages such as a low carbon footprint, short energy payback period, and compatibility with eco‐solvents. However, the use of hazardous solvents continues to dominate the best‐performing OSCs, mainly because of the challenges of controlling phase separation and domain crystallinity in eco‐solvents. In this study, we combined the solvent vapor treatment of CS2 and thermal annealing to precisely control the phase separation and domain crystallinity in PM6:M‐Cl and PM6:O‐Cl systems processed with the eco‐solvent o‐xylene. This method resulted in a maximum power conversion efficiency (PCE) of 18.4%, which is among the highest values reported for sustainable binary OSCs. Furthermore, the fabrication techniques were transferred from spin coating in a nitrogen environment to blade printing in ambient air, retaining a PCE of 16.0%, showing its potential for high‐throughput and scalable production. In addition, a comparative analysis of OSCs processed with hazardous and green solvents was conducted to reveal the differences in phase aggregation. This work not only underscores the significance of sustainability in OSCs but also lays the groundwork for unlocking the full potential of open‐air‐printable sustainable OSCs for commercialization.

A mesoporous layer was constructed by a donor-based nanoparticulate water-ink, which facilitates the infiltration of the acceptor, allowing the fabrication of efficient organic solar cells with a high thickness tolerance.