Metal-halide perovskites offer great potential to realize low-cost and flexible next-generation solar cells. Low-temperature processed organic hole-transporting layers play an important role in advancing device efficiencies and stabilities. Inexpensive and stable hole-transporting materials are highly desirable towards the scaling up of perovskite solar cells. Here, we report a new group of aniline-based enamine hole-transporting materials obtained via a one-step synthesis procedure, This article is protected by copyright. All rights reserved. without using a transition metal catalyst, from very common and inexpensive aniline precursors. This results in a material cost reduction to less than 1/5 of that for the archetypal spiro-OMeTAD. Perovskite solar cells using an enamine V1091 hole transporting material exhibit a champion power conversion efficiency of over 20%. Importantly, the unsealed devices with V1091 retain 96% of their original efficiency after storage in ambient air, with a relative humidity of 45% for over 800 hours, while the devices fabricated using spiro-OMeTAD dropped down to 42% of their original efficiency after aging. Additionally, these materials can be processed via both solution and vacuum processes, which we believe will open up new possibilities for interlayers used in large-area all perovskite tandem cells, as well as many other optoelectronic device applications.
The development of the simple synthesis schemes of organic semiconductors can have an important contribution to the advancement of related technologies. In particular, one of the fields where the high price of the hole‐transporting materials may become an obstacle toward successful commercialization is perovskite solar cells. Herein, enamine‐based materials that are capable of undergoing cross‐linking due to the presence of two vinyl groups are synthesized. It is shown that new compounds can be thermally polymerized, making the films resistant to organic solvents. This can allow the use of a wet‐coating process for the deposition of the perovskite absorber film, without the need for orthogonal solvents. Cross‐linked films are used in perovskite solar cells, and, upon optimization of the film thickness, the highest power conversion efficiency of 18.1% is demonstrated.
To attain commercial viability, perovskite solar cells (PSCs) have to be reasonably priced, highly efficient, and stable for a long period of time. Although a new record of a certified power conversion efficiency (PCE) value over 25% was achieved, PSC performance is limited by the lack of hole-transporting materials (HTMs), which extract positive charges from the light-absorbing perovskite layer and carry them to the electrode. Here, we report spirobifluorene-based HTMs with finely tuned energy levels, high glass-transition temperature, and excellent charge mobility and conductivity enabled by molecularly engineered enamine arms. HTMs are synthesized using simple condensation chemistry, which does not require costly catalysts, inert reaction conditions, and time-consuming product purification procedures. Enamine-derived HTMs allow the fabrication of PSCs reaching a maximum PCE of 19.2% and stability comparable to spiro-OMeTAD. This work demonstrates that simple enamine condensation reactions could be used as a universal path to obtain HTMs for highly efficient and stable PSCs.
Stabilizing the high-performing perovskite solar cells (PSCs) with low-cost and simply affordable hole-transporting materials (HTMs) has been identified as an ongoing ambitious challenge. Herein, a series of enamine-based HTMs having different central heteroatoms (C, N, O, and S) and a number of enamine branches is designed and synthesized. The impact of varied central heteroatom cores is investigated in-depth including thermal, photophysical, and photovoltaic properties. Importantly, molecularly engineered HTMs are obtained by a single condensation reaction without the need for expensive catalysts, inert reaction conditions, or tedious product purification. PSCs with a power conversion efficiency (PCE) of over 20% can be realized with the triphenylamine core HTM (V1435), a result comparable with spiro-OMeTAD. HTMs based on tetraphenylmethane (V1431) and diphenyl sulfide (V1434) cores give a slightly lower performance under similar device fabrication conditions. This work demonstrates how rational molecular engineering of a simple condensation approach can produce HTMs for high-performing PSCs without sacrificing the PCE.
Perovskite Solar Cells Solution‐processing of the photoactive layer on top of the hole‐transporting material can be challenging.Solvent damage leads to the formation of direct contact with the electrode, and consequently to reduced performance parameters. In article number http://doi.wiley.com/10.1002/solr.202000597, Vytautas Getautis and co‐workers show that cross‐linking of the organic semiconductor is advantageous for application in the p‐i‐n perovskite solar cells.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.