Perovskite solar cells (PVSC) are a promising alternative to traditional silicon-based solar cells due to their high power conversion efficiency and low cost. However, achieving long-term stability has been one of the main challenges in its development.
NOW, A team of researchers from the City University of Hong Kong (CityU) has developed an innovative non-volatile multifunctional additive that can improve the efficiency and stability of perovskite solar cells. modulate the growth of the perovskite film. This simple and effective strategy has great potential to facilitate the commercialization of PLSCs.
Although PVSCs have attracted much attention in recent years, their efficiency and stability continue to be affected by the high energy loss associated with defects embedded at perovskite interfaces and grain boundaries. Therefore, the intrinsic quality of the metal halide perovskite film is very important to increase the energy conversion efficiency and the long-term stability of PVSCs.
Much previous research has focused on improving film morphology and quality with volatile additives. However, these additives tend to escape from the film after annealing, creating a void at the interface between the perovskite and the substrate.
CityU researchers found that adding a multifunctional molecule (4-guanidino benzoic acid hydrochloride, (GBAC)) to the perovskite precursor forms a hydrogen-bridged midphase and modulates the growth kinetics of the perovskite film . The additive allows the formation of large crystal grains of perovskite and a constant growth of grains from the bottom to the surface of the film..
This module can also serve as an effective defect passivation binder, a method of reducing perovskite film defect density, in annealed perovskite film due to its non-volatility, resulting in significant reduction in density loss. by non-radiative recombination and an improvement in the quality of the film.
Improved film morphology results in a significant reduction in defect density, increasing the power conversion efficiency of inverted perovskite (pin) solar cells by up to 24.8% (24.5% certified) with a low energy loss of 0.36 eV.
Additionally, non-encapsulated devices exhibit improved thermal stability beyond 1000 hours under continuous heating at 65 ± 5°C in a nitrogen-filled glove box, maintaining 98% of original efficiency.
This efficient method can also be applied to broadband perovskites and large area devices to reduce voltage losses and increase efficiency.
In the future, the researchers plan to further extend the molecule and optimize the structure of the device through compositional and interfacial engineering. They will also focus on making large-area devices.