Scientists create an additive to successfully improve the stability of perovskite solar cells

• Perovskite solar cells (PVSCs) are a promising choice to standard silicon-based solar cells because of their high power-conversion performance and low cost. Nevertheless, one of the significant challenges in their growth has actually been achieving long-lasting stability.

Lately, a study group from City University of Hong Kong (CityU) made an advancement by developing a cutting-edge multifunctional as well as non-volatile additive which can boost the effectiveness as well as stability of perovskite solar cells by modulating perovskite film growth. This simple and also reliable technique has wonderful prospective for helping with the commercialization of PVSCs.

"This type of multifunctional additive can be normally made use of to alter perovskite structures for making highly effective and also stable perovskite solar cells. The high-quality perovskite films will certainly allow the upscaling of large-area photovoltaic panels," discussed Professor Alex Jen Kwan-yue, Lee Shau Kee Chair Professor of Materials Science as well as Director of the Hong Kong Institute for Clean Energy at CityU, who led the study.

PVSCs have brought in substantial attention as a result of their excellent solar energy conversion performance (PCE). Considering that perovskites can be transferred from services onto the fabrication surfaces, PVSCs have the possible to be used in building-integrated photovoltaics (BIPV), wearable devices, as well as solar farm applications.

However, the performance and stability are still affected by the severe energy loss related to defects embedded at the interfaces and also grain borders of the perovskites. Therefore, the intrinsic top quality of perovskite film plays an essential duty in figuring out the possible efficiency and also stability of PVSCs.

Although many previous study studies have concentrated on enhancing the film morphology and high quality with unstable additives, these ingredients have a tendency to escape from the film after annealing, creating a void at the perovskite-substrate user interface.

To deal with these issues, the CityU researchers created a basic however efficient strategy of modulating the perovskite film growth to boost the film top quality. They located that by including a multifunctional molecule (4-guanidinobenzoic acid hydrochloride, (GBAC)) to the perovskite precursor, a hydrogen-bond-bridged intermediate phase is developed and modulates the condensation to achieve premium perovskite films with big perovskite crystal grains and meaningful grain development from all-time low to the surface of the film.

This molecule can also act as a reliable defect passivation linker (an approach to minimize the defect density of perovskite film) in the annealed perovskite film because of its non-volatility, resulting in significantly decreased non-radiative recombination loss as well as improved film quality.

Their experiments revealed that the defect density of perovskite films can be considerably decreased after introducing GBAC. The power conversion effectiveness of inverted (p-i-n) perovskite solar cells based on the changed perovskites was enhanced to 24.8% (24.5% certified by the Japan Electrical Safety & Environment Technology Laboratories), which is amongst the highest possible values reported in the literature.

Likewise, the total energy loss of the device was decreased to 0.36 eV, standing for among the most affordable energy losses among the PVSC devices with high power conversion efficiency.

In addition, the unencapsulated devices exhibit boosted thermal stability beyond 1,000 hours under continuous heating at 65 ± 5 ° C in a nitrogen-filled glovebox while preserving 98% of the initial efficiency.

The team showed the basic applicability of this method for different perovskite compositions and large-area devices. For instance, a bigger location device (1 cm2) in the experiment delivered a high PCE of 22.7% with this approach, indicating superb potential for producing scalable, highly reliable PVSCs.

"This work gives a clear path to attaining maximized perovskite film quality to facilitate the development of highly effective and stable perovskite solar cells as well as their upscaling for functional applications," said Professor Jen.

In the future, the team intends to further expand the molecular structures as well as optimize the device structure through compositional and interfacial engineering. They will likewise concentrate on the fabrication of large-area devices.

The findings were released in the journal Nature Photonics.