ADVERTISEMENT

Using Heterocyclic Halides To Improve Photovoltaic Properties And Stability

The societal pressure to move towards sustainable energy has made photovoltaics the main competitor for cost-competitive energy sources. As of now, the photovoltaics market is dominated by silicon technology and has shown grid parity; however, the energy payback time remains higher in this established technology. With the increasing use of renewable energy, thin-film photovoltaic technology (CIGS, CdTe, Kesterites, Dye, and organic solar cells) will also gradually increase its market share.

The current decade has witnessed the unprecedented rise in the investigation of perovskite materials for solar cell fabrication owing to their excellent semiconducting and light-harvesting behavior. Apart from solar cells, it has also shown success in light-emitting diodes (LEDs) and laser fabrication at lab scale. Solution-processed perovskite solar cells have made stunning advancement in a short time frame, though they also suffer from intrinsic issues such as charge migration and stability.

ADVERTISEMENT

Device long-term stability, triggered by thermal and moisture-induced degradation, remains a challenging task, and currently, this is seen as a barrier to its technological exploitation. The impulsive loss of iodide is argued to be a potential path in device degradation. By adopting the strategy of using an iodide-rich passivation layer on top of the perovskite layer, several unwanted reactions can be retarded.

Our understanding is that this iodide-rich passivation layer will passivate the surface defects and fill the grain boundaries, which in turn will reduce the non-radiative recombination losses and ultimately push device photovoltaic performance. More importantly, it will keep the performance linear across the time scale. The natural desire in iodide encompassing material such as imidazolium iodide, to lose iodide will act as a good passivant for perovskites. It is a known fact that, due to MAPbI3‘s three-dimensional structure, it rotates across the axis, and this leads to ion migration inside the perovskites.

An additional source of iodine will act as a reservoir to suppress iodide loss and will also fill the grain boundaries. In this article (Nano Energy, 2018) we describe solar cell performance using meticulously engineered material and its integration in working devices. The present investigation demonstrates that the judicious choice of passivation layer can indeed passivate the surface and also solve the issue of ion migration, along with improved photovoltaic performance. This has been achieved through a simple approach by passivating perovskite surface and its molecular encapsulation by imidazolium iodide.

The simple strategy will facilitate other iodide rich imidazolium salts to be further exploited in thin film organic-inorganic perovskite solar cells and push the community to optimize this structure for maximum light harvesting. In a recent report, using a similar approach and covering perovskites with graphene was also found to suppress the iodide loss, and it showed significant improvement in perovskite stability.

ADVERTISEMENT
Republished with permission from Elsevier from: https://doi.org/10.1016/j.nanoen.2018.05.035

In summary, the present work not only provides vital insights to address the daunting challenges for future stable perovskite optoelectrical device development but also put forward the potential of an iodine-rich layer as a multipurpose interfacial spacer. This will lead to the possibilities to explore other halide (iodide) rich spacer layers which have a negative bearing on light-harvesting abilities in perovskites.

These findings are described in the article entitled Surface passivation of perovskite layers using heterocyclic halides: Improved photovoltaic properties and intrinsic stability, recently published in the journal Nano Energy. This work was conducted by Manuel Salado from the Basque Center for Materials and Swiss Federal Institute of Technology Lausanne and Shahzada Ahmad from the Basque Center for Materials and IKERBASQUE, Basque Foundation for Science.

Comments

READ THIS NEXT

Computational Mass Spectrometry Deepens The Understanding Of Metabolisms

Metabolomics aims at providing information about “metabolome,” the comprehensive small molecules of living organisms, which has been used for elucidating […]

Anaerobic Digestion: A Promising Solution To Waste

In an energy constrained world, anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW) i.e. food residues and […]

Tackling Type 2 Diabetes At Its Root By Directly Shrinking Adipose Tissue

The incidence of obesity in the United States is soaring. Four in 10 adult Americans are considered obese based on […]

Volcanoes: Large Metal Emitters

Sulfur dioxide (SO2) and halogens (HCl, HF, HBr) are the most abundant acidic species in volcanic plumes, affecting public health […]

Hybrid Materials As Potential NIR Absorbers For Organic Electronics

Modern society is largely a plastic-based culture in which organic (carbon-based) plastics have become more ubiquitous than other common materials […]

How To Write A Cursive Capital F

Are you interested in learning how to write a cursive capital F? You can read on to learn how to […]

Scientists Discover Strange New Kind Of Quantum Material

This past week an amazing discovery was made. A team of scientists has stumbled upon a new kind of quantum […]

Science Trends is a popular source of science news and education around the world. We cover everything from solar power cell technology to climate change to cancer research. We help hundreds of thousands of people every month learn about the world we live in and the latest scientific breakthroughs. Want to know more?